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Modern heat pumps are truly a marvel, especially when you get one designed for heating and not just an AC-unit running in reverse. They're very common in Sweden
by fastbeef 8y ago
Modern heat pumps are truly a marvel, especially when you get one designed for heating and not just an AC-unit running in reverse. They're very common in Sweden and can easily warm an entire house even at -20 C.
Whenever this topic appears on HN I want to get on my soapbox and yell "INSULATION PEOPLE, INSULATION!". Most houses I've seen outside of the Nordics have shit-all insulation and that's depsite it working both ways - house stays cooler in the summer. It's such a small cost to add during construction and it pays off in a year or two, tops.
Modern, newly built houses in Sweden, way above the arctic circle, require less than 5000 kWh per year to heat and generate hotwater.
- NeedMoreTea 8y agoUK is finally getting there, but we have a very long way to go. Our housing is mostly bloody awful for insulation, draught proofing, and sensible forms of heating. The very worst is anything 60s-90s, particularly if there's a flat roof. We've only been hearing about how well Sweden and other Nordics do insulation, community heating, heat pumps etc for about 40 or 50 years. Various combined heat and power, insulation, passive houses etc would turn up on things like Tomorrow's World (60s-90s technology TV series) fairly often, like it was some sort of breakthrough new discovery. Well it was, to the UK, I guess.
- pjc50 8y agoThe UK's deeply dysfunctional planning/housing system contributes to that. Land is expensive, building your own home on purchased land quite rare due to bureaucracy of planning permission.
- noir_lord 8y agoI live in a flat that was built mid 90's and it's a disaster from a heating and cooling point of view. Ventiliation is shit, one side never gets the sun so the outer wall is cold which means condensation is a daily battle, I basically run a big heavy duty dehumidifier from mid-autumn to mid-spring (at least its not a net loss, it dumbs a fair amount of heat as a byproduct so I can run the heaters less). It's rented though so not something I can fix until I buy a property in a few years.
- henrikschroder 8y agoThere's a joke in Sweden: "Hey, do you know why the English put their pipes on the outside of their houses?" "No?" "It's so they can reach them easier to thaw them when they freeze!" And then everyone laughs. ...and then you learn that it's not a joke, and then you cry.
- wil421 8y agoAre houses in the Nordics framed with wood? I was having a discussion with someone the other day about houses in the U.K. They felt stone houses were far superior to the wood ones in the US. I tried to convince him about insulation being much better in wood frames homes in mild and cold climates to no avail. My exposure to the Nordics is limited but in the pictures I’ve seen there were lots of wood single family houses.
- m_eiman 8y agoFor small houses wooden frames are most common by far.
- fastbeef 8y ago95% wooden frame, typically 45mm+190mm+45mm insulation.
- garmaine 8y agoIn all seriousness, what are the advantages of stone? It doesn't hold up in an earthquake, it doesn't insulate, and it can't be renovated after the fact. I've encountered this mentality before and am absolutely baffled by it.
- mfoy_ 8y agoProbably an emotional thing, "set in stone", a sense of permanency, etc.
- hutzlibu 8y agoYeah well, the pyramids still stand today 4000 years later. So the "emotional thing" might have some ground in reality.
- maratd 8y ago> In all seriousness, what are the advantages of stone? If done right, it is likely the most durable material to use for siding. Will last for hundreds of years. Same with bricks if well maintained. All other kinds of siding deteriorate quickly in comparison. I am keeping an eye on the new cement siding that's now on the market, that's very interesting.
- deleted 8y ago[deleted]
- leguminous 8y agoAir sealing is also critical. The insulation can be defeated if unconditioned air can leak into the house and conditioned air can leak out. It's a difficult thing to get right because it requires attention to detail and if done poorly it can result in moisture problems.
- fastbeef 8y agoIt is indeed critical and all new houses in Sweden are tested for leaks under pressure. Those that leak sufficiently little get to call themselves Passivhus and you have some taxation benefits.
- daveFNbuck 8y agoHow do they test that?
- leguminous 8y agoAt least in the US, blower door testing: https://en.m.wikipedia.org/wiki/Blower_door https://en.m.wikipedia.org/wiki/Blower_door
- thomk 8y agoI've had this done before, very, very informative. Those machines are like $3K to buy, you can hire someone to come out and do it, but this seems like a perfect DIY project.
- masklinn 8y agoAn other very informative thing to get done is thermal imaging of the walls (from inside and outside both). Very good at uncovering damp spots and water infiltration too.
- leguminous 8y agoA handful of US states have also made blower door testing mandatory in new homes, but we still have a long way to go. A few states don't even have state-wide building codes, much less efficiency requirements.
- mixmastamyk 8y agoHave been suffering in our apartment with single-pane windows this winter in Los Angeles. :-(
- mmartinson 8y agoHas it been a particularly cold winter there?
- massivecali 8y agoParts of LA just got snow recently.
- maxxxxx 8y agoI had some parts of my windshield frozen a while ago. That is really rare.
- Rebelgecko 8y agoWe're on track to have the coldest February since the 1950s, so by that set of standards it's particularly cold. However I didn't get a lot of sympathy from a friend of mine in Minneapolis when I told him how miserable it was walking to my car when it was 50° outside
- CNJ7654 8y agoIt's funny how flexible our comfortable temperature range is. When fall rolls around, 50° is sweatshirt and jeans weather. When spring comes, 50° is shorts and tank top weather
- mixmastamyk 8y agoReasonably certain there are no apts in MN with drafty windows from the 60s. Thanks, NIMBYs.
- justinph 8y agoYou would be wrong.
- mmartinson 8y agoIs -20 a practical limit for them working in your experience or is this just a convenient low number for the sake of an example. I assume that is Sweden the temp can drop below that at times in the middle of winter. Are housing using them using a backup heat source as well? On the west coast of Canada we'd probably never hit -20, but lots of other parts of the country do regularly.
- fastbeef 8y agoIt's a nice round number that the manufacturers use a reference point, it's not a hard limit. In 99% of the cases, the out door unit will be connected to a indoor counterpart that has a 9kW resistance heating element what will aid with heating as the outdoor unit loses efficency with dropping temperature.
- rb808 8y agoThe problem with heat pumps in cold temperatures is that the compressor (outside) unit has to go below the air temperature in order to absorb heat. I'm not sure the difference, but I'd expect it to have to go to -30, -40, -50, at those temperatures its difficult to build mechanical devices that are going to work reliably for 10+ years.
- alkonaut 8y agoYou get lower efficiency for lower temps, so for a typical Swedish house you just need to consider how many days in the year you expect sub -20-25 temps. For e.g Stockholm this is only very few days per year so a good idea is to have a fireplace (which is nice anyway) as a backup in the very rare cases it’s -25 or colder. In northern Sweden you can’t be surprised to see a month of -20 some years, so you probably want either a bigger heat pump, expect to use more direct electric in the pump (the heat pumps are air/water so the houses are heated with circulating water, not hot air) or something else entirely like geothermal.
- throw0101a 8y agoThere are some Mitsubishi and Panasonic units that (IIRC) can work in -30C.
- criddell 8y agoWhat about at the other end of the spectrum? We wanted temperature control in our garage so we had a heat pump installed. The company told us that heat pumps stop working for cooling around 38 C which kind of sucks because that's when we want it the most.
- mikeash 8y agoTechnically, any standard AC unit is a heat pump, so that doesn’t make a whole lot of sense.
- function_seven 8y agoIsn't the refrigeration loop "tuned" for a particular operating range? Like, if I want a heat pump for extracting heat from cold winter air, the operating envelope will be set up differently than for a unit designed to dump heat into hot summer air. I'm guessing here. I just know that the outside condenser and inside evaporator (in a cooling setup) need to match each other pretty well to avoid damage to the compressor or inefficient operation.
- extrapickles 8y agoIt mostly depends on what refrigerant is used. All heat pumps need to be able to change the phase of the refrigerant, which becomes too hard above or below certain temperatures. You can extend the range by having a higher pressure pump, but that reduces efficiency.
- mikeash 8y agoI'm sure there are many parameters to tune, although I don't know the details. But a "heat pump" is just a machine that pumps fluid in a certain way to make one end hot and another end cold. With a traditional AC, the hot end is placed outside and the cold end inside. What the HVAC folks call a "heat pump" is a particular variety that can reconfigure itself to put the hot end inside. If you were so inclined, you could heat a space by taking an AC and turning it backwards so the hot end was inside. (This would be pretty dumb unless you needed to heat stuff up in the summer, since the temperature range it's built for would be all wrong otherwise, but it works.) I'm sure there are heat pumps that don't cool well when the temperature is too high, but I don't think it's a general property of all of them.
- baybal2 8y ago> I want to get on my soapbox and yell "INSULATION PEOPLE, INSULATION!". I'm joining you in that. I'm in Dubai at the moment thanks to airspace closure over Pakistan. I noticed that richer Middle Eastern countries are the few places outside of the ex-USSR where foamed concrete picked up popularity as an insulation material. Seems to be a very popular choice for detached housing here. I also noticed that despite the fabulous wealth, glass curtainwalls are not so widespread here. Even the most "skyscrapery" skyscrapers here have some solid walls and/or external shading (even Burj Khalifa on some levels.)
- ip26 8y agoI've gone through the exercise of retrofitting insulation. Unfortunately there are a few things that are extremely hard to get past. 2x4 walls can only be insulated to R-13 or so unless you're replacing the siding. Subslab insulation can pretty much only be done when it's poured. Joist insulation & air sealing can be very hard to get to. I can only hope 2x6 framing becomes more common, the subslab insulation has started to become code.
- rootusrootus 8y ago2x6 framing should be nearly universal on new construction, which calls for R19 according to the international building code.
- Scoundreller 8y agoAhh, so this is why building my 3 season shack is damn near impossible financially.
- bluGill 8y ago2x4 can be insulated much higher - around R26. You need to use expensive closed cell foam to do this. It is much cheaper to build with 2x6 which gets you to R19 with cheap insulation.
- ip26 8y agoYou can't easily retrofit spray foam though. Either the drywall or sheathing needs to come off, unless the cavity was empty, and even then it doesn't fill evenly if sprayed in a single hole.
- everial 8y ago> I've gone through the exercise of retrofitting insulation. Based on your experiences what do you recommend? (or what sources do you recommend consulting to learn more about retrofitting older buildings?)
- 8y ago
- floatrock 8y ago> It's such a small cost to add during construction and it pays off in a year or two, tops. Classic market failure: operational costs don't factor into home buying decisions prominently, so whatever small added construction cost is borne by the homebuilders (the cost of added insulation doesn't quite result in an equal increase of selling price). Short of instituting a carbon tax that would make operational costs of heating suddenly more prominent and priced accordingly, this is a great case for efficiency standards in homebuilding. Suppose your home came with an "energy star" HVAC rating...
- mattbk1 8y agoYou can build a LEED house the same way as any other building: https://freshome.com/2014/10/09/what-is-a-leed-certified-home/ https://freshome.com/2014/10/09/what-is-a-leed-certified-hom....
- floatrock 8y agoYes, of course you can find anything if you're looking specifically for it. At HN we talk about scale, though, so how do we make everyone look for efficiency?
- saagarjha 8y agoTell them it's cheaper to live in.
- URSpider94 8y agoConsumers are notably horrible, and for good reason (neuropsych/behavioral economics has studied this in depth), at making rational total cost of ownership calculations. You can argue all you want that it SHOULD be enough to share lifetime costs, but it doesn’t work. Just look at people who still buy incandescent light bulbs because they are cheaper at the cash register, even though they will save a multiple of the cost of the bulb over its lifetime.
- schnevets 8y agoThe Google X spinoff Dandelion Energy is now testing in my area, and I have been experiencing frequency illusion with geothermal heating since I saw an ad for it. I do wonder how X's technology compares to existing household products, though.
- jjtheblunt 8y agoWhat sort of insulation is in use in Sweden?
- alkonaut 8y agoAround 300mm for new construction (a foot in freedom units). Glass wool or styrofoam. Slightly less in older houses.
- roel_v 8y ago"styrofoam" Nitpick / clarification: this is not 'EPS' which is what is commonly known in the US a styrofoam (although according to Wikipedia, the trademarked name 'Styrofoam' actually referes to XPS); so not the white grainy stuff e.g. some disposable coffee cups are made from. Modern insulation is done with PIR, PUR or XPS.
- deleted 8y ago[deleted]
- brightball 8y agoI have a 2 story house with a heat pump for the upstairs...and I hate it. It causes so many problems that we just keep the heat very low up there so that the heat drift from the 1st floor furnace does most of the work. When it runs, you can never set it higher than 2 degrees F above the current temperature and if you do that when it's even close to freezing outside the unit will build up a think layer of ice around the casing...which just makes it spin constantly until we turn it off to go manually de-ice it. It's the most hated piece of equipment in my entire home. Do you have a reference for one of these more effective modern heat pumps? I've been sincerely planning to install geothermal when this thing dies.
- Thlom 8y agoMaybe you have a really old one or an ac-unit in reverse? My pump works perfectly well in -15 C and I have no problems with ice. In Norway most pumps are Toshiba and Mitsubishi. F.ex Mitsubishi FH35.
- tlb 8y agoGroundwater systems are much better. My parents house in Ottawa has one, and it works fine through -30 C nights. There's a source well about 30' deep with a pump at the bottom, and a return well some distance away. That provides a constant supply of water around 5-10 C for the heat exchanger. It is a complicated system -- lots of valves and reservoirs and so on, but very efficient and doesn't need much maintenance.
- SketchySeaBeast 8y agoI wonder how we could work this for an urban setting - could we use the water lines?
- tlb 8y agoIt consumes a lot of water, so it'd be expensive if you send the outflow down the drain. If you pump the outflow back into the fresh water supply, you have to worry about contamination from everyone's heat exchanger. In a dense urban setting, you can heat homes with water heated at the local power plant, either fossil or nuclear. https://en.wikipedia.org/wiki/Cogeneration https://en.wikipedia.org/wiki/Cogeneration
- thinkcontext 8y agoIt seems residential natural gas prices in Sweden are almost 4 times what they are in the US! Show what a carbon tax can do in changing economic decision making. https://www.statista.com/statistics/702735/household-natural-gas-prices-in-selected-countries/ https://www.statista.com/statistics/702735/household-natural...
- Scoundreller 8y agoAnd how fearful people are of depending on Russia.
- alkonaut 8y agoThis might be because no one in Sweden knows what “residential natural gas” is. I haven’t heard about anyone heating their house with natural gas. Residential gas is used for gas stoves in some old (exclusive) areas of stockholm. Oil used to be a thing but these days it’s usually electric (heat pump) or geothermal.
- nray 8y agoHomes are heated with communal hot water, wood gassification (pellet burners), heat exchange with the ground or deeper bore-holes, or electricity. Not much gas, heating oil was gone by the 80's sometime.
- Sharlin 8y agoThis demonstrates the danger of assumptions. As others have commented, "residential natural gas" simply isn't a thing in the Nordics.
- Kluny 8y agoMy dad is such a pain in the ass about this - he'll turn the heat down to 15 degrees in any room that's not currently occupied, and whenever they leave the house. So the place is always uncomfortably cold, there are hot spots/cold spots and drafts. Meanwhile there's minimal insulation in the attic and zero insulation under the floors, and a huge basement that's always cozy and warm all winter, despite the fact that there's no heating in there. Then he complains about the heating bill and blames me for it (because I cranked the heat when I came over for dinner one night). What a mystery.
- vondur 8y agoTo be fair, here in California, all newer homes have insulation preinstalled. I think there may still be a tax credit to help have your home insulated if it doesn't have any insulation.
- tomatotomato37 8y agoOne thing to add to insulation, make sure your cooking appliances have decent internal insulation too; otherwise you may find your gas oven overwhelming whatever natural radiative qualities your home has, even with all the windows open. Not a fun thing to learn when your AC gets knackered in the florida heat.
- nray 8y agoMany Swedish suburbs are supplied with communal hot water for heating (fjärrvärme) produced by burning non-recyclable rubbish or maybe a local factory. The last stage of houses built near us was so thermally efficient that the supplier refused to extend the heating network, as there was not enough consumption to generate a profit. When I lived in New Zealand I could see my breath indoors in the winter. Insulation? I'm a convert.
- hourislate 8y agoInsulation is probably the most important mechanical energy saving feature of a house. Unfortunately it is behind the drywall and as they say "out of sight and out of mind". We built a very large cottage (3000 sq/ft) in Northern Ontario, Canada. The entire house had a continuous envelope of a minimum of 4-5 inches of Closed Cell Foam (2 lb) ( https://www.demilec.com/ https://www.demilec.com/ ) . Installed a Geo-Thermal Unit with in floor heating through out the basement and forced air everywhere else. We also have a high efficiency fireplace stove. It can be minus 40 C outside and you only need a couple of logs in the fireplace to keep the entire cottage very warm. You can change out your furnace/AC/Heat Pump anytime, but try tearing off all the drywall in your entire house to replace the fiberglass insulation that doesn't work or was installed incorrectly. Spray Foam Insulation pays for itself and to think it's only around $3.00 a sq/ft at 3 " thick installed. People have no problem paying more for carpeting or tile floors, strange....
- bzbarsky 8y ago> require less than 5000 kWh per year to heat and generate hotwater For what size house, if I might ask?
- rebuilder 8y agoYes, insulation, but that's not without its problems either. If you're adding insulation to an old house you have to consider that the ventilation system in that house is probably gravity-based. What that means is hot air moves upward, through an unheated attic in the type of house I'm thinking of, and replacement air is pulled in through the breathable structures of the walls. When you insulate such a house heavily, that air intake is compromised and you lose ventilation. So for an insulated house you may need to add mechanical ventilation, which underpressurizes the house. You now need to add air vents, but if you don't have enough of them, replacement air may get drawn e.g. from the understructure of the house, pulling soil microbes into the air with it. Also, if you insulate in such a way that the breathability is compromised, you risk moisture problems, which lead to mold. In particular, adding modern fibreglass insulation to an old house is very problematic, because that type of insulation should not be allowed to draw moisture as it will not dry out and will grow moldy, and wood structures in contact with it may rot. Basically, moisture control and insulation is a tough problem. In modern houses the solution is to have an airtight layer of plastic sheeting between the insulation and drywall, but those houses should also have been designed from the ground up to have an active, mechanical ventilation system. Based on experiences here in Finland, a lot of such buildings built in the 60's and 70's have developed severe problems, and frankly even new projects seem to have issues all the time. The more you insulate, the more you have to take care that moisture does not gather in the insulation because you no longer have airflow that would dry it out.
- leguminous 8y ago> In modern houses the solution is to have an airtight layer of plastic sheeting between the insulation and drywall [...] In a building that will be air conditioned, putting plastic sheeting between the insulation and drywall is a bad idea. The problem is that any moisture in the (comparatively warmer) insulation cavity will condense on the (comparatively cooler) plastic sheeting, wetting out the insulation and causing mold and rot. They also prevent the wall from drying to the inside. It works fine in cold climates that are do not install air conditioning, as I assume is the case in Finland. In the majority of the US, even up to the Canadian border, many new houses have AC. https://www.buildingscience.com/documents/digests/bsd-106-understanding-vapor-barriers https://www.buildingscience.com/documents/digests/bsd-106-un...
- henrikschroder 8y ago> Modern, newly built houses in Sweden Also worth mentioning is that Sweden pushes a lot of retrofitting of older houses, not just new ones. In the 90's, triple-pane windows became a legally mandated standard, so every old apartment building that only had double-pane windows had to add a third pane somehow, or change out all the windows or whatever. A lot of older buildings are also adding extra insulation, one complex I used to live in that was built in the 1940's did that after I moved out. They stripped off all the outer layers to get to the brick, added foam insulation blocks, and redid the plaster finish. When I lived there, the complex did the mandatory energy certification and got a shit score, so that's why they had to do it.
- MisterOctober 8y agoI experienced a modern heat pump in action for the first time about a year ago, when I was visiting family in the very cold US state of Maine -- creaky old [and ill-insulated] house in the woods heated up in a jiffy! Hats off to the engineers who work on this stuff. p.s. even though the refrigerants are bad, still a mile better than the old oil heaters everybody used when I was a kid