11 ms·

Simple Techniques for Lowering the Cost of Zero-Energy Homes

121 points by catawbasam 9y ago

dmm 9y ago
There are so many simple things we can do to make more energy efficient homes but builders and buyers don't care. They will happily spend thousands on dumb things that are highly visible but won't spend a few hundred on something as simple as sealing ducts so 30% of your conditioned air isn't lost. A carbon tax would go a long way to solving this by giving people correct price information so they can make good decisions. If energy was more expensive people would demand more energy efficient homes.
- ballenf 9y ago
  I'd rather see something like nutrition labels but instead efficiency measures in various areas for new homes before a tax. Having bought a number of homes it's surprisingly painful and infeasible to compare apples-to-apples upfront. "Easy" to get details on a per-house level but just about impossible to filter your search early based on efficiency.
  - dforrestwilson 9y ago
    I built an Energy Star certified home in Georgia for maybe 5% more than the cost would have been otherwise. It's been a great rental since we left the area. Utility bills or estimated utility bills are the clearest way we have found to advertise the value to renters.
  - pcardoso 9y ago
    This is already a thing at least here in Portugal. This is a energy efficiency certificate that is now mandatory when renting and selling a house: http://www.adene.pt/sites/default/files/documentos/certificado_adene_reh.v2.pdf http://www.adene.pt/sites/default/files/documentos/certifica... (PDF)
    - ptaipale 9y ago
      All of EU, but in my opinion it's mostly a scam. Companies that perform this certification lobbied to make it mandatory whenever selling a house. However, the certificate does not tell you the real energy consumption. The calculation is based on "weighting factors" for whatever energy production format the politicians want to favor currently, so at least where I live, in Finland - where energy consumption really matters in the winter - when you buy a house, you pay for a certificate that is not very useful, and then you ask the previous owner for the actual energy bills he had, to asses the real cost and consumption. The latter is, of course, what everyone did already before this certificate system. OK, it's just a few hundred euros per sale. A bigger problem in the various energy saving initiatives is that houses built to this code sometimes develop very nasty air quality problems (due to air not changing in some places fast enough, or subtle leakages in the airtight balloon where you live) which then forces costly renovations and in the worst case destroy health.
  - FidelCashflow 9y ago
    A blower door test is a great measure of a homes energy efficiency and it's quite cheap to have done. Not sure if YT links are OK but check out Matt Risinger Blower Door Test https://www.youtube.com/watch?v=msZ_E-4GFs8 https://www.youtube.com/watch?v=msZ_E-4GFs8
  - dx034 9y ago
    In many parts of Europe (probably all of EU), energy consumption has to be given when renting out or selling homes. Often, they also have to be advertised for public buildings.
  - sarcher 9y ago
    There are a couple of certification programs out there that are well regarded (with vary levels of real-world usage): Energy Star: https://www.energystar.gov/newhomes/ https://www.energystar.gov/newhomes/ Zero Energy Ready Homes: https://energy.gov/eere/buildings/zero-energy-ready-home https://energy.gov/eere/buildings/zero-energy-ready-home Passive House: http://www.phius.org/home-page http://www.phius.org/home-page LEED for Homes: https://www.usgbc.org/cert-guide/homes https://www.usgbc.org/cert-guide/homes And my favorite, the Pretty Good House: http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/pretty-good-house http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/p... Honestly, if you're buying a new home and the builder hasn't ponied up for Energy Star, you've got to wonder where their priorities are - it's not a difficult program to achieve. You can find Energy Star builders here: https://www.energystar.gov/index.cfm?fuseaction=new_homes_partners.locator https://www.energystar.gov/index.cfm?fuseaction=new_homes_pa... I agree, there is little transparency on the home-buying front, largely because adherence to one of these certifications is still pretty rare. Also, it's rarely taken into account in the appraisal process.
    - cyguy 9y ago
      There is also the HERS Index, which is probably the most popular: https://www.resnet.us/hers-index https://www.resnet.us/hers-index. 22% of homes received HERS Index Scores in 2016. It is a simple score that indicates the efficiency of a home. A score of 0 represents Net-Zero, and score of 100 represents a "typical home". If you're buying a home (and you care), you should ask if it has been HERS Rated and to see the HERS Certificate. Source for 22%: http://www.resnet.us/blog/national-renewable-energy-laboratory-research-finds-the-22-of-new-home-completed-in-the-u-s-in-2016-were-hers-rated/ http://www.resnet.us/blog/national-renewable-energy-laborato...
      - sarcher 9y ago
        Nice catch, I should have included the HERS Index. It's a decent standard with wide adoption.
- insaneirish 9y ago
  > There are so many simple things we can do to make more energy efficient homes but builders and buyers don't care. Here's an article that talks about this unfortunate disconnect: http://www.finehomebuilding.com/2017/04/26/dont-build-better-houses http://www.finehomebuilding.com/2017/04/26/dont-build-better...
- justinsb 9y ago
  Are there things that can cost-effectively be done in existing houses? That seems a good way to create demand for greater efficiency - demonstrate the value on a smaller scale first.
  - maxerickson 9y ago
    The high impact retrofits are better windows, more insulation and new mechanical systems. Getting insulation into walls is hard and at some point doesn't help a lot if there are air gaps. New mechanical systems aren't really cost effective (because operating costs aren't that high; hundreds of dollars of monthly savings on a $10,000 upgrade). For people that use a lot of cooling replacing an old air conditioner can be a big win.
  - catawbasam 9y ago
    Yes. Low-flow shower-heads can pay for themselves in a few weeks. DIY air-sealing with caulk and sprayfoam will also pay for itself in a few weeks in most old homes. LED lights pay for themselves in a few months if you get a good price on-line or from a home center. Added attic insulation is another thing that will pay for itself in a few months DIY, or a few years if you pay to have it done. BuildItSolar has a slightly dated but still useful section about cutting your energy use in half at: http://builditsolar.com/References/Half/Half.htm http://builditsolar.com/References/Half/Half.htm
- damnfine 9y ago
  I, like many others, live in an area where there is already roughly enough housing. There is little space to build a new 1 family home, not does it make sense to. If I tore down my current house, It would make economic sense to turn it into a crappy medium rent apartment building. Building a home is already information overload, you need to make it trendy or economical. If it was clear the TCO was lower with this tech, it WILL sell. But buyers are conservative, and for good reason. That new tech is now their 30 year investment.
  - dublinben 9y ago
    It is abundantly clear that the TCO of zero-energy or energy-positive homes is lower than traditional construction. The nearly nonexistent utility costs are immediately apparent. The math will only shift more in their favor as energy costs continue to rise.
    - toomuchtodo 9y ago
      Energy costs won't rise: energy demand growth has halted across the first world (aging population + efficiency gains), and adding renewables each year is going to drive the price of energy down. People should still build energy efficient dwellings, but there is no energy price spike around the corner (for electricity at least). An hour of sunlight on Earth supplies enough energy to power humanity for a year.
      - Retric 9y ago
        Inflation still increases the long term costs. This makes a very important difference when home loans are ~4%.
        toomuchtodo 9y ago
        Inflation is not a given. Notice how inflation can't be pushed up in first world countries, even with trillions of dollars of quantitive easing by central banks [1]. Yes, you can create asset bubbles in the stock market and real estate. But the cost of everything else (besides RE, equities, health care, and education) is going down. The cost of energy will continue to decline, because we are awash in renewable energy, and the collection mechanisms are technology that continues to decline in cost precipitously. [1] https://www.bloomberg.com/news/articles/2017-08-16/fed-minutes-may-show-battle-lines-hardening-over-soft-inflation https://www.bloomberg.com/news/articles/2017-08-16/fed-minut...
- baybal2 9y ago
  Not entirely sure about that statement. In Russia, they certainly do. A good building is considered one if it has proper thermal design, and definitely commands higher price. In this country, some provinces spend 1/3 of their GDP on energy. Here, buildings with 30cm+ insulation and triple glazed, metalised, air-tight windows are not rare.
nickhalfasleep 9y ago
It's interesting to think about a few code changes to reduce the cost of a house too. What if you removed the 120V outlets and wiring from bedrooms and went to just 12V, or USB, or Power over Ethernet) for lighting and small appliance power? A smart "Home Computer" that was the whole home. With more efficient lighting, entertainment, you could cut down on the amount of copper in the building, and the expectation of energy usage. Of course keep the power places you need it, like the kitchen, bathroom, or entertainment center.
- brians 9y ago
  How do you vacuum? When you need to use power tools, just run cords or stick to batteries?
  - jlebrech 9y ago
    you can get a roomba, i'm sure those run off batteries.
    - nsxwolf 9y ago
      They're fine for daily maintenance, but sometimes you need to go in with the heavy hitter.
  - agumonkey 9y ago
    I wonder if there are low power alternative to vacuum, depending on the surface of course. For actual power tools well.. I help my kids like indoor biking :heh:
    - ashark 9y ago
      > I wonder if there are low power alternative to vacuum, depending on the surface of course. If the famous vacuum cleaner repairman Reddit AMA is to be believed, the overwhelming majority of vacuums purchased are so in name only, producing far too weak a vacuum to do any good and relying on carpet-damaging powerful brushes to do the cleaning. So we don't even have working light-ish vacuums, let alone low-power ones, let alone affordable light and low power ones. The ones that actually do what they're supposed to are still heavy and expensive (and, I assume, power hungry).
ZeroGravitas 9y ago
I'm amazed that society level efficiencies like these aren't considered a bigger deal. If people are burning more gas than they need to that's less money for them to spend on everything else. It's like the whole country living on credit card debt and not worrying about the interest because it's in the future. It's making you literally poorer and giving you nothing in return, just due to a lack of foresight and planning.
- PoachedSausage 9y ago
  Its probably a combination of general 'tragedy of the commons'/'somebody else's problem' and humans being bad at planning for the future. See also cigarette smoking.
- jaclaz 9y ago
  >If people are burning more gas than they need to that's less money for them to spend on everything else. It's like the whole country living on credit card debt and not worrying about the interest because it's in the future. It's making you literally poorer and giving you nothing in return, just due to a lack of foresight and planning. Only it doesn't work that way. The deal with the builder has traditionally been (only an example): 1) you pay upfront US$ 40,000 more for the construction of the house in an energy efficient manner 2) we promise you that this will allow you to save US$ 3,000 per year in energy 3) for whatever reasons the savings actualy result in US$ 2,000 per year instead, but that is "normal" and within the expected calculation error, and anyway we already got the additional US$ 40,000, sue us. 4) part of the added US$ 40,000 go in part (heating, cooling, ventilation, windows) that require some added maintenance costs and that won't anyway last 20 years and/or will have higher replacement costs. 5) also consider how the "savings" are dependent on actually living in the house, if you - say - go six months away closing the house, you won't spend anything for energy, while you will be paying anyway the added US$ 40,000 on your mortgage payment, same thing if you rent it, the people living in the house will get the savings, you will still be paying the same.
  - kevstev 9y ago
    1- I am not sure what kind of house you are talking about, but typical costs for energy efficiency result in less than a 10% increase in total costs. 2- ok. 3- The savings can be much greater than that. Insulation alone has an amazing bang for the buck. And its passive. 4- Added maintenance for windows? They don't require a diamond polisher to be cleaned. Who replaces their windows and doors every 20 years? What specifically needs extra maintenance? 5- Even if you are not living in the house, you can capture a higher profit margin by including utilities in the rental price, or marketing it as an energy efficient house. This is a real edge case though. Interest rates are about 3.5% now. Even in your inflated cost estimate, that translates to $700 in interest for 6 months. Not exactly game changing IMHO. You are also missing an important point- energy efficient houses also tend to be a lot more comfortable, there are less drafts, less swings in temperature, less affected by outside noise. And you get the satisfaction of not having to care so much if energy prices increase.
nwah1 9y ago
In developed nations, most people live in urban areas, and urbanization is continuing. In many cities, building costs are smaller than the unimproved value of the site. Around half the value is a typical figure. Although, in certain districts in San Francisco, London, and New York the average land-to-building ratio is near 90%. Sort on the land share column on this data sheet, and you'll see that SF is near that. Don't have data offhand for London, but given the reporting on it, it actually seems higher. https://datatoolkits.lincolninst.edu/subcenters/land-values/metro-area-land-prices.asp https://datatoolkits.lincolninst.edu/subcenters/land-values/...
hourislate 9y ago
There are two simple things a home builder/renovator can do to make any dwelling super efficient. Insulate with Spray Foam and install a Geo Thermal HVAC system. The problem is when you tell the customer that Spray Foam at 3" / per sq/ft costs approx $3 dollars (approx 16-20k to insulate a 3000 sq/ft home)they look at you like you raped their sister and killed their mother. Yet when you quote them a kitchen for 40k they smile and have no problems paying $140 a linear ft for counter tops or $10 a sq/ft for carpeting. Cosmetic items can be replaced at anytime (hardwood floors, tiles, kitchens, etc) but try to rip off all the drywall in your home to re-insulate or dig/drill up your property to install geo thermal. People need to invest more into the mechanical structure of the home instead of the cosmetic details if they are serious about building an efficient dwelling. The building code at all levels needs to reflect a higher level of efficiency and government programs in the form of tax credits should be used to promote these upgrades and it would go a long way in helping reduce emissions. I keep telling people that Spray Foam and Geo Thermal is free. It pays for itself rather quickly while providing a comfortable environment to live in.
- baybal2 9y ago
  No, a lot of building are leaking heat by design. Some are incompatible with insulation by design. A building needs to be designed from ground up for efficiency
- sarcher 9y ago
  Spray foam products are excellent for a variety of reasons, but their effects can be overstated concerning air sealing (one of the techniques in the original article - I know you aren't directly addressing air sealing in your comment). Spray foam provides excellent air sealing immediately after install in as little as 1.5 inches[0]. However, spray foam also doesn't address wood-to-wood contact areas where air leakage can occur. The best air-sealing results are typically achieved with a taped exterior sheathing layer, or a taped sheet membrane (located on the interior, exterior, or mid-wall). The most common air-sealing method that works is the use of Huber Zip panels with Zip taped seams (or another quality acrylic tape). One caveat - I say most common because it is a very common material, but that doesn't mean the correct air-sealing methods are always used. [0]http://www.greenbuildingadvisor.com/articles/dept/musings/air-leakage-through-spray-polyurethane-foam http://www.greenbuildingadvisor.com/articles/dept/musings/ai...
swsieber 9y ago
So, all of this seems to apply to house construction. What's the best way to retrofit a house, to make make it more energy efficient? Or is there no way and I should just weep bitterly?
- bovine3dom 9y ago
  Insulating your attic is the most effective and cheap thing for most people; cavity wall insulation is more expensive but also effective if you have the right kind of wall. Then it's unexotic stuff like making sure doors have decent seals on them. Double glazing is pricey and some way down the list. Retrofitting better insulation to your walls if you don't have cavities is very expensive (you'll have to redecorate the house, too) but effective.
  - sarcher 9y ago
    Most likely your house has double glazed windows - I only see single-glazed windows in antique wooden windows these days (but perhaps it's different outside of New England). Good triple-glazed windows are expensive, but there are some vinyl triple systems that are reasonably priced. Anderson and Pella both have triple glazed options, for example. There is also a relatively inexpensive (compared to imported European windows) option for tilt-turn windows now available: http://logicwd.com/ http://logicwd.com/ I haven't installed them myself, but I've bought other systems from that vendor and have been happy.
    - dx034 9y ago
      > Most likely your house has double glazed windows - I only see single-glazed windows in antique wooden windows these days (but perhaps it's different outside of New England). Internationally speaking, the UK is very far behind when it comes to insulation. Single glazed windows are still standard in many houses. Energy prices are cheap compared to the rest of the continent and costs are still one of the highest.
    - swsieber 9y ago
      How can you tell if a window is single, double or triple glazed? Is there an easy way, or would I have to have a specialist look at my windows?
nvahalik 9y ago
I've always been really curious to know how ventilation is supposed to work. In an RV if you're cooking or venting in the shower the directions pretty clearly say something to the effect of "open a window"—those things are sealed pretty tight and the air you're pushing out needs to be replaced with something... So when you are taking a shower and use a ceiling vent (louvered, I assume) where does the replacement air come from if you're sealing up the house? Otherwise you'd just be creating a pressure difference and the fan wouldn't be moving a lot of air. What am I missing?
- PoachedSausage 9y ago
  Heat recovery ventilation. The warm moist outgoing air gives up some of its energy to warm the incoming air. https://en.wikipedia.org/wiki/Heat_recovery_ventilation https://en.wikipedia.org/wiki/Heat_recovery_ventilation
- sarcher 9y ago
  Air-tightness is a spectrum - a reasonably tight house still leaks enough to make up most ventilation needs introduced by an exhaust only ventilation system. Very tight homes may need air inlets (literally fancy holes in the wall somewhere), or a balanced ventilator system. Appliances that can draft are also an issue. Some are generally discouraged, like drafting water heaters, and some will require their own air inlet, like wood burning fireplaces. "2011 Ventilation Guide" by Armin Rudd is a very readable introduction to this subject. https://buildingscience.com/bookstore/books/2011-ventilation-guide https://buildingscience.com/bookstore/books/2011-ventilation... For online reading, here is a very short introduction: http://www.greenbuildingadvisor.com/green-basics/ventilation-choices-three-ways-keep-indoor-air-fresh http://www.greenbuildingadvisor.com/green-basics/ventilation... Here is a longer discussion: http://www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ventilation-system http://www.greenbuildingadvisor.com/blogs/dept/musings/desig...
- jaclaz 9y ago
  The issue with a whole lot of "new" and "energy saving" houses is often connected to poor ventilation. Set aside for one moment the vapour from the shower, and from either the dryer or coming from the natular drying of washed clothes, there is the human generated vapour and that created by cooking. In modern houses (without an efficient ventilation system) the airtightness causes condensation/moisture (usually in corners of the rooms or wherever there is a thermal bridge) which usually evolves in this (or that) form of mould or mildew. Some (not all) heat insulation materials make the walls (besides airtight) also watertight, which makes the issue worse. The idea of creating openings to allow the air in, which may be good in - say - a kitchen where the air also exits normally via the extractor hood or chimney (at the cost of some energy/heating/cooling dispersion) does not work in other rooms, where the openings most of the time either do not guarantee the circulation of air or behave as "heat dispersion" holes, negating all the savings that the airtightedness gave you. Not only, people breath and emits, beside vapour, C02. I know that it sounds obvious, but if you don't let (fresh) air in, before or later you will find yourself in a low-oxygen environment. Having "normal", not airtight, windows and doors makes continuous ventilation of the interior of the house a "natural" phenomenon (with a cost in energy). If you make an "airtight" house, additionally "watertight" (as an example using polystirene or similar for heat insulation) you are essentially living in a unhealthy environment, unless you provide a suitable ventilation system, and a ventilation system without an air-to-air exchange (to re-use part of the heath or cold) will negate most of the saving effects of the added insulation/airtightedness. So, as pointed out by PoachedSausage, heat recovery ventilation is an actual need in energy saving houses, but it is still rather uncommon.
wolfwyrd 9y ago
This came from the Zero Energy Project[1] which also has floor plans. [1] http://zeroenergyproject.org/2017/07/24/simple-techniques-lowering-cost-zero-energy-homes/ http://zeroenergyproject.org/2017/07/24/simple-techniques-lo...
mmagin 9y ago
The thing that annoys me is that both good passive solar design and utilizing the lessons of "vernacular architecture" are both crippled by trying to make houses that have roughly the same appearance that people are familiar with.
- tveita 9y ago
  Do you have any examples of what unfettered designs might look like?
  - mmagin 9y ago
    Not really, I'm a dilettante at this. https://en.wikipedia.org/wiki/Village_Homes https://en.wikipedia.org/wiki/Village_Homes is one of the more successful developments that really focused on passive solar design that I'm aware of.
neuromancer2701 9y ago
This is all within the paradigm of convention construction. The thermal properties of compressed earth brick(CEB) make heating and cool a house a lot different. It would be interesting to see what the financial number are if CEB were used instead of modern stick housing.
WalterBright 9y ago
My house has large eaves on it. This shades the house in summer, and keeps the walls and windows dry during the Seattle rain. This really cuts down on maintenance costs. The house is also designed to use the "stack effect" to passively cool it in summer, though experience with it shows it could have been done better. I didn't care too much to super seal air leaks, because of potential indoor air quality issues.
- blacksmythe 9y ago
  >> didn't care too much to super seal air leaks, because of potential indoor air quality issues. It is more energy efficient to open your windows each day (during the optimum daily temperature window), than to have low-level air flow all day. The time of day that you want air flow varies with the season.
ge96 9y ago
That name seems misleading... "zero-energy" and then lower zero?
chiefofgxbxl 9y ago
One thing that I still have yet to see in the United States is a house that is designed without central AC. An energy tip I see quite a bit is to program your thermostat. But why can't I program my thermostat on a per room basis? [0] If I'm on my computer at night and just want to heat my room, why do I instead have to heat the entire house/apartment? What a waste! I think this is still achievable using existing systems. Keep the central unit, but modify the air ducts to have programmable valves. Then you can choose which rooms to have the ducts open/closed to. Sure, there will see some loss, but much better than maintaining temp for the entire building. [0] https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x709.jpg https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x...
- dragonwriter 9y ago
  > One thing that I still have yet to see in the United States is a house that is designed without central AC. Lots of houses in the US don't have central HVAC, and only non-central heating and non-central (or no) AC. > But why can't I program my thermostat on a per room basis? You can; system zoning [0] is a thing, even with central HVAC. > I think this is still achievable using existing systems. Keep the central unit, but modify the air ducts to have programmable valves. Yes, that's how the well-known and widely deployed (though not super-common in single-family homes, because of the up-front cost) technology works. [0] http://home.howstuffworks.com/home-thermostat4.htm http://home.howstuffworks.com/home-thermostat4.htm
- sliverstorm 9y ago
  Owning a better built house and having sealed it up and all, it turns out it doesn't seem like that would help terribly much. With good design, heat gain or loss is very limited in the first place. We get most of our heat from a few south windows, and body heat. Once I shade the windows, it will be just bodies, which heat the house the same no matter the room. Plus the building is usually designed as a unit- the envelope is sealed and insulated, room-to-room is not at all. So the heat or cool just one room strategy I think is only compelling in a poorly designed building.

121 points by catawbasam 9y ago

dmm 9y ago

There are so many simple things we can do to make more energy efficient homes but builders and buyers don't care. They will happily spend thousands on dumb things that are highly visible but won't spend a few hundred on something as simple as sealing ducts so 30% of your conditioned air isn't lost. A carbon tax would go a long way to solving this by giving people correct price information so they can make good decisions. If energy was more expensive people would demand more energy efficient homes.

ballenf 9y ago
I'd rather see something like nutrition labels but instead efficiency measures in various areas for new homes before a tax. Having bought a number of homes it's surprisingly painful and infeasible to compare apples-to-apples upfront. "Easy" to get details on a per-house level but just about impossible to filter your search early based on efficiency.
- dforrestwilson 9y ago
  I built an Energy Star certified home in Georgia for maybe 5% more than the cost would have been otherwise. It's been a great rental since we left the area. Utility bills or estimated utility bills are the clearest way we have found to advertise the value to renters.
- pcardoso 9y ago
  This is already a thing at least here in Portugal. This is a energy efficiency certificate that is now mandatory when renting and selling a house: http://www.adene.pt/sites/default/files/documentos/certificado_adene_reh.v2.pdf http://www.adene.pt/sites/default/files/documentos/certifica... (PDF)
  - ptaipale 9y ago
    All of EU, but in my opinion it's mostly a scam. Companies that perform this certification lobbied to make it mandatory whenever selling a house. However, the certificate does not tell you the real energy consumption. The calculation is based on "weighting factors" for whatever energy production format the politicians want to favor currently, so at least where I live, in Finland - where energy consumption really matters in the winter - when you buy a house, you pay for a certificate that is not very useful, and then you ask the previous owner for the actual energy bills he had, to asses the real cost and consumption. The latter is, of course, what everyone did already before this certificate system. OK, it's just a few hundred euros per sale. A bigger problem in the various energy saving initiatives is that houses built to this code sometimes develop very nasty air quality problems (due to air not changing in some places fast enough, or subtle leakages in the airtight balloon where you live) which then forces costly renovations and in the worst case destroy health.
- FidelCashflow 9y ago
  A blower door test is a great measure of a homes energy efficiency and it's quite cheap to have done. Not sure if YT links are OK but check out Matt Risinger Blower Door Test https://www.youtube.com/watch?v=msZ_E-4GFs8 https://www.youtube.com/watch?v=msZ_E-4GFs8
- dx034 9y ago
  In many parts of Europe (probably all of EU), energy consumption has to be given when renting out or selling homes. Often, they also have to be advertised for public buildings.
- sarcher 9y ago
  There are a couple of certification programs out there that are well regarded (with vary levels of real-world usage): Energy Star: https://www.energystar.gov/newhomes/ https://www.energystar.gov/newhomes/ Zero Energy Ready Homes: https://energy.gov/eere/buildings/zero-energy-ready-home https://energy.gov/eere/buildings/zero-energy-ready-home Passive House: http://www.phius.org/home-page http://www.phius.org/home-page LEED for Homes: https://www.usgbc.org/cert-guide/homes https://www.usgbc.org/cert-guide/homes And my favorite, the Pretty Good House: http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/pretty-good-house http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/p... Honestly, if you're buying a new home and the builder hasn't ponied up for Energy Star, you've got to wonder where their priorities are - it's not a difficult program to achieve. You can find Energy Star builders here: https://www.energystar.gov/index.cfm?fuseaction=new_homes_partners.locator https://www.energystar.gov/index.cfm?fuseaction=new_homes_pa... I agree, there is little transparency on the home-buying front, largely because adherence to one of these certifications is still pretty rare. Also, it's rarely taken into account in the appraisal process.
  - cyguy 9y ago
    There is also the HERS Index, which is probably the most popular: https://www.resnet.us/hers-index https://www.resnet.us/hers-index. 22% of homes received HERS Index Scores in 2016. It is a simple score that indicates the efficiency of a home. A score of 0 represents Net-Zero, and score of 100 represents a "typical home". If you're buying a home (and you care), you should ask if it has been HERS Rated and to see the HERS Certificate. Source for 22%: http://www.resnet.us/blog/national-renewable-energy-laboratory-research-finds-the-22-of-new-home-completed-in-the-u-s-in-2016-were-hers-rated/ http://www.resnet.us/blog/national-renewable-energy-laborato...
    - sarcher 9y ago
      Nice catch, I should have included the HERS Index. It's a decent standard with wide adoption.
insaneirish 9y ago
> There are so many simple things we can do to make more energy efficient homes but builders and buyers don't care. Here's an article that talks about this unfortunate disconnect: http://www.finehomebuilding.com/2017/04/26/dont-build-better-houses http://www.finehomebuilding.com/2017/04/26/dont-build-better...
justinsb 9y ago
Are there things that can cost-effectively be done in existing houses? That seems a good way to create demand for greater efficiency - demonstrate the value on a smaller scale first.
- maxerickson 9y ago
  The high impact retrofits are better windows, more insulation and new mechanical systems. Getting insulation into walls is hard and at some point doesn't help a lot if there are air gaps. New mechanical systems aren't really cost effective (because operating costs aren't that high; hundreds of dollars of monthly savings on a $10,000 upgrade). For people that use a lot of cooling replacing an old air conditioner can be a big win.
- catawbasam 9y ago
  Yes. Low-flow shower-heads can pay for themselves in a few weeks. DIY air-sealing with caulk and sprayfoam will also pay for itself in a few weeks in most old homes. LED lights pay for themselves in a few months if you get a good price on-line or from a home center. Added attic insulation is another thing that will pay for itself in a few months DIY, or a few years if you pay to have it done. BuildItSolar has a slightly dated but still useful section about cutting your energy use in half at: http://builditsolar.com/References/Half/Half.htm http://builditsolar.com/References/Half/Half.htm
damnfine 9y ago
I, like many others, live in an area where there is already roughly enough housing. There is little space to build a new 1 family home, not does it make sense to. If I tore down my current house, It would make economic sense to turn it into a crappy medium rent apartment building. Building a home is already information overload, you need to make it trendy or economical. If it was clear the TCO was lower with this tech, it WILL sell. But buyers are conservative, and for good reason. That new tech is now their 30 year investment.
- dublinben 9y ago
  It is abundantly clear that the TCO of zero-energy or energy-positive homes is lower than traditional construction. The nearly nonexistent utility costs are immediately apparent. The math will only shift more in their favor as energy costs continue to rise.
  - toomuchtodo 9y ago
    Energy costs won't rise: energy demand growth has halted across the first world (aging population + efficiency gains), and adding renewables each year is going to drive the price of energy down. People should still build energy efficient dwellings, but there is no energy price spike around the corner (for electricity at least). An hour of sunlight on Earth supplies enough energy to power humanity for a year.
    - Retric 9y ago
      Inflation still increases the long term costs. This makes a very important difference when home loans are ~4%.
      - toomuchtodo 9y ago
        Inflation is not a given. Notice how inflation can't be pushed up in first world countries, even with trillions of dollars of quantitive easing by central banks [1]. Yes, you can create asset bubbles in the stock market and real estate. But the cost of everything else (besides RE, equities, health care, and education) is going down. The cost of energy will continue to decline, because we are awash in renewable energy, and the collection mechanisms are technology that continues to decline in cost precipitously. [1] https://www.bloomberg.com/news/articles/2017-08-16/fed-minutes-may-show-battle-lines-hardening-over-soft-inflation https://www.bloomberg.com/news/articles/2017-08-16/fed-minut...
baybal2 9y ago
Not entirely sure about that statement. In Russia, they certainly do. A good building is considered one if it has proper thermal design, and definitely commands higher price. In this country, some provinces spend 1/3 of their GDP on energy. Here, buildings with 30cm+ insulation and triple glazed, metalised, air-tight windows are not rare.

nickhalfasleep 9y ago

It's interesting to think about a few code changes to reduce the cost of a house too. What if you removed the 120V outlets and wiring from bedrooms and went to just 12V, or USB, or Power over Ethernet) for lighting and small appliance power? A smart "Home Computer" that was the whole home. With more efficient lighting, entertainment, you could cut down on the amount of copper in the building, and the expectation of energy usage. Of course keep the power places you need it, like the kitchen, bathroom, or entertainment center.

brians 9y ago
How do you vacuum? When you need to use power tools, just run cords or stick to batteries?
- jlebrech 9y ago
  you can get a roomba, i'm sure those run off batteries.
  - nsxwolf 9y ago
    They're fine for daily maintenance, but sometimes you need to go in with the heavy hitter.
- agumonkey 9y ago
  I wonder if there are low power alternative to vacuum, depending on the surface of course. For actual power tools well.. I help my kids like indoor biking :heh:
  - ashark 9y ago
    > I wonder if there are low power alternative to vacuum, depending on the surface of course. If the famous vacuum cleaner repairman Reddit AMA is to be believed, the overwhelming majority of vacuums purchased are so in name only, producing far too weak a vacuum to do any good and relying on carpet-damaging powerful brushes to do the cleaning. So we don't even have working light-ish vacuums, let alone low-power ones, let alone affordable light and low power ones. The ones that actually do what they're supposed to are still heavy and expensive (and, I assume, power hungry).

ZeroGravitas 9y ago

I'm amazed that society level efficiencies like these aren't considered a bigger deal. If people are burning more gas than they need to that's less money for them to spend on everything else. It's like the whole country living on credit card debt and not worrying about the interest because it's in the future. It's making you literally poorer and giving you nothing in return, just due to a lack of foresight and planning.

PoachedSausage 9y ago
Its probably a combination of general 'tragedy of the commons'/'somebody else's problem' and humans being bad at planning for the future. See also cigarette smoking.
jaclaz 9y ago
>If people are burning more gas than they need to that's less money for them to spend on everything else. It's like the whole country living on credit card debt and not worrying about the interest because it's in the future. It's making you literally poorer and giving you nothing in return, just due to a lack of foresight and planning. Only it doesn't work that way. The deal with the builder has traditionally been (only an example): 1) you pay upfront US$ 40,000 more for the construction of the house in an energy efficient manner 2) we promise you that this will allow you to save US$ 3,000 per year in energy 3) for whatever reasons the savings actualy result in US$ 2,000 per year instead, but that is "normal" and within the expected calculation error, and anyway we already got the additional US$ 40,000, sue us. 4) part of the added US$ 40,000 go in part (heating, cooling, ventilation, windows) that require some added maintenance costs and that won't anyway last 20 years and/or will have higher replacement costs. 5) also consider how the "savings" are dependent on actually living in the house, if you - say - go six months away closing the house, you won't spend anything for energy, while you will be paying anyway the added US$ 40,000 on your mortgage payment, same thing if you rent it, the people living in the house will get the savings, you will still be paying the same.
- kevstev 9y ago
  1- I am not sure what kind of house you are talking about, but typical costs for energy efficiency result in less than a 10% increase in total costs. 2- ok. 3- The savings can be much greater than that. Insulation alone has an amazing bang for the buck. And its passive. 4- Added maintenance for windows? They don't require a diamond polisher to be cleaned. Who replaces their windows and doors every 20 years? What specifically needs extra maintenance? 5- Even if you are not living in the house, you can capture a higher profit margin by including utilities in the rental price, or marketing it as an energy efficient house. This is a real edge case though. Interest rates are about 3.5% now. Even in your inflated cost estimate, that translates to $700 in interest for 6 months. Not exactly game changing IMHO. You are also missing an important point- energy efficient houses also tend to be a lot more comfortable, there are less drafts, less swings in temperature, less affected by outside noise. And you get the satisfaction of not having to care so much if energy prices increase.

nwah1 9y ago

In developed nations, most people live in urban areas, and urbanization is continuing. In many cities, building costs are smaller than the unimproved value of the site. Around half the value is a typical figure. Although, in certain districts in San Francisco, London, and New York the average land-to-building ratio is near 90%. Sort on the land share column on this data sheet, and you'll see that SF is near that. Don't have data offhand for London, but given the reporting on it, it actually seems higher. https://datatoolkits.lincolninst.edu/subcenters/land-values/metro-area-land-prices.asp https://datatoolkits.lincolninst.edu/subcenters/land-values/...

hourislate 9y ago

There are two simple things a home builder/renovator can do to make any dwelling super efficient. Insulate with Spray Foam and install a Geo Thermal HVAC system. The problem is when you tell the customer that Spray Foam at 3" / per sq/ft costs approx $3 dollars (approx 16-20k to insulate a 3000 sq/ft home)they look at you like you raped their sister and killed their mother. Yet when you quote them a kitchen for 40k they smile and have no problems paying $140 a linear ft for counter tops or $10 a sq/ft for carpeting. Cosmetic items can be replaced at anytime (hardwood floors, tiles, kitchens, etc) but try to rip off all the drywall in your home to re-insulate or dig/drill up your property to install geo thermal. People need to invest more into the mechanical structure of the home instead of the cosmetic details if they are serious about building an efficient dwelling. The building code at all levels needs to reflect a higher level of efficiency and government programs in the form of tax credits should be used to promote these upgrades and it would go a long way in helping reduce emissions. I keep telling people that Spray Foam and Geo Thermal is free. It pays for itself rather quickly while providing a comfortable environment to live in.

baybal2 9y ago
No, a lot of building are leaking heat by design. Some are incompatible with insulation by design. A building needs to be designed from ground up for efficiency
sarcher 9y ago
Spray foam products are excellent for a variety of reasons, but their effects can be overstated concerning air sealing (one of the techniques in the original article - I know you aren't directly addressing air sealing in your comment). Spray foam provides excellent air sealing immediately after install in as little as 1.5 inches[0]. However, spray foam also doesn't address wood-to-wood contact areas where air leakage can occur. The best air-sealing results are typically achieved with a taped exterior sheathing layer, or a taped sheet membrane (located on the interior, exterior, or mid-wall). The most common air-sealing method that works is the use of Huber Zip panels with Zip taped seams (or another quality acrylic tape). One caveat - I say most common because it is a very common material, but that doesn't mean the correct air-sealing methods are always used. [0]http://www.greenbuildingadvisor.com/articles/dept/musings/air-leakage-through-spray-polyurethane-foam http://www.greenbuildingadvisor.com/articles/dept/musings/ai...

swsieber 9y ago

So, all of this seems to apply to house construction. What's the best way to retrofit a house, to make make it more energy efficient? Or is there no way and I should just weep bitterly?

bovine3dom 9y ago
Insulating your attic is the most effective and cheap thing for most people; cavity wall insulation is more expensive but also effective if you have the right kind of wall. Then it's unexotic stuff like making sure doors have decent seals on them. Double glazing is pricey and some way down the list. Retrofitting better insulation to your walls if you don't have cavities is very expensive (you'll have to redecorate the house, too) but effective.
- sarcher 9y ago
  Most likely your house has double glazed windows - I only see single-glazed windows in antique wooden windows these days (but perhaps it's different outside of New England). Good triple-glazed windows are expensive, but there are some vinyl triple systems that are reasonably priced. Anderson and Pella both have triple glazed options, for example. There is also a relatively inexpensive (compared to imported European windows) option for tilt-turn windows now available: http://logicwd.com/ http://logicwd.com/ I haven't installed them myself, but I've bought other systems from that vendor and have been happy.
  - dx034 9y ago
    > Most likely your house has double glazed windows - I only see single-glazed windows in antique wooden windows these days (but perhaps it's different outside of New England). Internationally speaking, the UK is very far behind when it comes to insulation. Single glazed windows are still standard in many houses. Energy prices are cheap compared to the rest of the continent and costs are still one of the highest.
  - swsieber 9y ago
    How can you tell if a window is single, double or triple glazed? Is there an easy way, or would I have to have a specialist look at my windows?

nvahalik 9y ago

I've always been really curious to know how ventilation is supposed to work. In an RV if you're cooking or venting in the shower the directions pretty clearly say something to the effect of "open a window"—those things are sealed pretty tight and the air you're pushing out needs to be replaced with something... So when you are taking a shower and use a ceiling vent (louvered, I assume) where does the replacement air come from if you're sealing up the house? Otherwise you'd just be creating a pressure difference and the fan wouldn't be moving a lot of air. What am I missing?

PoachedSausage 9y ago
Heat recovery ventilation. The warm moist outgoing air gives up some of its energy to warm the incoming air. https://en.wikipedia.org/wiki/Heat_recovery_ventilation https://en.wikipedia.org/wiki/Heat_recovery_ventilation
sarcher 9y ago
Air-tightness is a spectrum - a reasonably tight house still leaks enough to make up most ventilation needs introduced by an exhaust only ventilation system. Very tight homes may need air inlets (literally fancy holes in the wall somewhere), or a balanced ventilator system. Appliances that can draft are also an issue. Some are generally discouraged, like drafting water heaters, and some will require their own air inlet, like wood burning fireplaces. "2011 Ventilation Guide" by Armin Rudd is a very readable introduction to this subject. https://buildingscience.com/bookstore/books/2011-ventilation-guide https://buildingscience.com/bookstore/books/2011-ventilation... For online reading, here is a very short introduction: http://www.greenbuildingadvisor.com/green-basics/ventilation-choices-three-ways-keep-indoor-air-fresh http://www.greenbuildingadvisor.com/green-basics/ventilation... Here is a longer discussion: http://www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ventilation-system http://www.greenbuildingadvisor.com/blogs/dept/musings/desig...
jaclaz 9y ago
The issue with a whole lot of "new" and "energy saving" houses is often connected to poor ventilation. Set aside for one moment the vapour from the shower, and from either the dryer or coming from the natular drying of washed clothes, there is the human generated vapour and that created by cooking. In modern houses (without an efficient ventilation system) the airtightness causes condensation/moisture (usually in corners of the rooms or wherever there is a thermal bridge) which usually evolves in this (or that) form of mould or mildew. Some (not all) heat insulation materials make the walls (besides airtight) also watertight, which makes the issue worse. The idea of creating openings to allow the air in, which may be good in - say - a kitchen where the air also exits normally via the extractor hood or chimney (at the cost of some energy/heating/cooling dispersion) does not work in other rooms, where the openings most of the time either do not guarantee the circulation of air or behave as "heat dispersion" holes, negating all the savings that the airtightedness gave you. Not only, people breath and emits, beside vapour, C02. I know that it sounds obvious, but if you don't let (fresh) air in, before or later you will find yourself in a low-oxygen environment. Having "normal", not airtight, windows and doors makes continuous ventilation of the interior of the house a "natural" phenomenon (with a cost in energy). If you make an "airtight" house, additionally "watertight" (as an example using polystirene or similar for heat insulation) you are essentially living in a unhealthy environment, unless you provide a suitable ventilation system, and a ventilation system without an air-to-air exchange (to re-use part of the heath or cold) will negate most of the saving effects of the added insulation/airtightedness. So, as pointed out by PoachedSausage, heat recovery ventilation is an actual need in energy saving houses, but it is still rather uncommon.

wolfwyrd 9y ago

This came from the Zero Energy Project[1] which also has floor plans. [1] http://zeroenergyproject.org/2017/07/24/simple-techniques-lowering-cost-zero-energy-homes/ http://zeroenergyproject.org/2017/07/24/simple-techniques-lo...

mmagin 9y ago

The thing that annoys me is that both good passive solar design and utilizing the lessons of "vernacular architecture" are both crippled by trying to make houses that have roughly the same appearance that people are familiar with.

tveita 9y ago
Do you have any examples of what unfettered designs might look like?
- mmagin 9y ago
  Not really, I'm a dilettante at this. https://en.wikipedia.org/wiki/Village_Homes https://en.wikipedia.org/wiki/Village_Homes is one of the more successful developments that really focused on passive solar design that I'm aware of.

neuromancer2701 9y ago

This is all within the paradigm of convention construction. The thermal properties of compressed earth brick(CEB) make heating and cool a house a lot different. It would be interesting to see what the financial number are if CEB were used instead of modern stick housing.

WalterBright 9y ago

My house has large eaves on it. This shades the house in summer, and keeps the walls and windows dry during the Seattle rain. This really cuts down on maintenance costs. The house is also designed to use the "stack effect" to passively cool it in summer, though experience with it shows it could have been done better. I didn't care too much to super seal air leaks, because of potential indoor air quality issues.

blacksmythe 9y ago
>> didn't care too much to super seal air leaks, because of potential indoor air quality issues. It is more energy efficient to open your windows each day (during the optimum daily temperature window), than to have low-level air flow all day. The time of day that you want air flow varies with the season.

ge96 9y ago

That name seems misleading... "zero-energy" and then lower zero?

chiefofgxbxl 9y ago

One thing that I still have yet to see in the United States is a house that is designed without central AC. An energy tip I see quite a bit is to program your thermostat. But why can't I program my thermostat on a per room basis? [0] If I'm on my computer at night and just want to heat my room, why do I instead have to heat the entire house/apartment? What a waste! I think this is still achievable using existing systems. Keep the central unit, but modify the air ducts to have programmable valves. Then you can choose which rooms to have the ducts open/closed to. Sure, there will see some loss, but much better than maintaining temp for the entire building. [0] https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x709.jpg https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x...

dragonwriter 9y ago
> One thing that I still have yet to see in the United States is a house that is designed without central AC. Lots of houses in the US don't have central HVAC, and only non-central heating and non-central (or no) AC. > But why can't I program my thermostat on a per room basis? You can; system zoning [0] is a thing, even with central HVAC. > I think this is still achievable using existing systems. Keep the central unit, but modify the air ducts to have programmable valves. Yes, that's how the well-known and widely deployed (though not super-common in single-family homes, because of the up-front cost) technology works. [0] http://home.howstuffworks.com/home-thermostat4.htm http://home.howstuffworks.com/home-thermostat4.htm
sliverstorm 9y ago
Owning a better built house and having sealed it up and all, it turns out it doesn't seem like that would help terribly much. With good design, heat gain or loss is very limited in the first place. We get most of our heat from a few south windows, and body heat. Once I shade the windows, it will be just bodies, which heat the house the same no matter the room. Plus the building is usually designed as a unit- the envelope is sealed and insulated, room-to-room is not at all. So the heat or cool just one room strategy I think is only compelling in a poorly designed building.