6 ms·

Heat pumps are obviously great in many ways. But fitting one is a big deal - they are quite expensive, they take a lot of work to fit, really require extensive

by twic 3y ago

Heat pumps are obviously great in many ways. But fitting one is a big deal - they are quite expensive, they take a lot of work to fit, really require extensive additional insulation, and there are all sorts of caveats to them that mean they aren't a straightforward replacement for a boiler. So i'm slightly mystified that we basically don't hear anything about fitting drainwater heat recovery [1], in which the lukewarm drain water from your shower is used to pre-warm the incoming cold water. It's extremely simple, pretty cheap, simple to fit, and can recover ~50% of the waste heat, of something which is tens of percent of the energy consumption of a household. By all means, get a heat pump. But get a heat exchanger on your shower first! [1] https://www.energy.gov/energysaver/drain-water-heat-recovery https://www.energy.gov/energysaver/drain-water-heat-recovery

averageRoyalty 2y ago
This sounds like an American viewpoint. In Australia, New Zealand and much of Europe they are pretty cheap to install, and rarely require additional insulation. It may be that they're relatively new to your area, so the demand is outstripping supply of installers who have been doing this for 30+ years and as such are charging to that effect.
SomaticPirate 3y ago
For most single family US homes (which are single story) this would likely be a nightmare to install and maintain. Definitely a cool idea but a leak or any maintenance might quickly undercut the cost savings
- PaulDavisThe1st 3y ago
  Just as an FYI: > Information obtained from the US Census Bureau’s Survey of Construction (SOC) and tabulated by NAHB, shows that the rising trend of single-story homes reversed in 2021. The share of single-story homes decreased in 2021 and the share of two or more stories homes started was greater than one story homes. This is in line with recent NAHB analysis of new single-family home size trends. https://eyeonhousing.org/2022/07/share-of-two-or-more-stories-new-homes-increased-in-2021/ https://eyeonhousing.org/2022/07/share-of-two-or-more-storie...
- sgerenser 3y ago
  Shouldn’t be a problem in any home (1 story or 2) with a basement or taller crawlspace, which is a significant fraction of U.S. homes.
Wohlf 3y ago
Speaking of heat pumps and water heat, I installed both a heat pump and hybrid water heater to save on electricity. The water heater doesn't seem to have made much of a difference in my electrical bill, my guess is the problem is peak demand so I should have gotten a much bigger tank than before. Ambient garage temperature may also be an issue but it exhausts outside and the garage is insulated so it generally stays above 55 degrees.
- cogman10 3y ago
  Make sure you are in energy saving mode. The default for these systems is to try and do quick recovery which likely isn't what you want.
- bluGill 3y ago
  While those save money, most people don't really use a lot of hot water and so the amount they can save is limited.
- alostpuppy 3y ago
  Ah. I installed one in a uninsulated garage and it was really a big savings. It’s basically a free ac for whatever space it’s installed in
uconnectlol 3y ago
they also aren't very hot and wont work in northern cities, but people will install them there anyway. "boiler" - is that jargon for multiple kinds of heating units or actually just boilers?
- twic 3y ago
  By boiler i mean the big box on the wall in the kitchen which burns natural gas to heat water. This may be a UK specific usage.
  - foresto 3y ago
    I think this is known as a tankless water heater in the US. (Tankless because you said it's on the wall.)
    - komadori 3y ago
      Boilers in the UK are usually mounted on the inside of an exterior wall to provide for venting exhaust gases outside. They may provide hot water on-demand without a tank (combi boiler) or fill a hot water cylinder on a schedule (system boiler) depending on type. Heating is typically provided by the boiler pumping hot water through a circuit of wall-mounted radiators regulated by TRVs (Thermostatic Radiator Valves).
  - sgerenser 3y ago
    Boilers are definitely much more common in the UK than US. I believe New England is one of the few areas of the US that has a relatively high percentage of homes with hydronic+boiler heating setups. In most other parts of the U.S., many people probably have no idea what a boiler even is.
    - mattpallissard 3y ago
      Pretty common in the Northwest part of the country as well.
- 3y ago
cogman10 3y ago
> But fitting one is a big deal - they are quite expensive, they take a lot of work to fit, really require extensive additional insulation I think this somewhat overblows the complexity of a heat pump. They are simply Air conditioners that can be ran in reverse. One valve is the difference between a heat pump and AC. Why they are so expensive is really just price gouging because they aren't as common. If you are in a home with forced air AC then installing a heatpump system couldn't be simpler and should be something you consider when updating your AC system. It's really just a matter of updating the compressor and maybe adding some smarts to avoid condensation. In fact, it's shocking to me that AC -> heatpump conversion kits haven't hit the market. > So i'm slightly mystified that we basically don't hear anything about fitting drainwater heat recovery [1], in which the lukewarm drain water from your shower is used to pre-warm the incoming cold water. It's extremely simple, pretty cheap, simple to fit, and can recover ~50% of the waste heat, of something which is tens of percent of the energy consumption of a household. Really interesting idea, but I assume you have to rip up the shower to accomplish this right? Also, I'm guessing clogged wastewater piping might be an issue right? That said, that'd be easily overcome by just running the lines side by side with maybe a simple copper connector for heat exchange.
- bluGill 3y ago
  What is mystifying to me is why governments allow air conditioners without that reversing valve to be installed. A simple change, and the more people installing a heat pump the cheaper those valves get.
  - ianburrell 3y ago
    I regret getting just an AC a while ago. I could have gotten a heat pump and used it for most of the heating. Even if I didn't get heat pump installed, one that could have been converted to heat pump without complete replacement would been nice.
- computerdork 3y ago
  Agree with your take. Recently helped install a heat pump at a single-family home (rental property) in the SF Bay Area. Actually, they aren't that much more expensive than AC's (mine cost about $9k for everything, but again, I did 35% of the work myself for a ducted 3 ton heat pump). And yeah, the installation is almost exactly the same as what you'd do for an AC. And, you don't need to add insulation, but we did (to the crawlspace), costing about $2.5k And, it's been running for about 3 months, and saved about ~$175/month in heating. wow. It'll pay for itself in about 7-8 years.
deleted 3y ago
[deleted]

by twic 3y ago

averageRoyalty 2y ago

This sounds like an American viewpoint. In Australia, New Zealand and much of Europe they are pretty cheap to install, and rarely require additional insulation. It may be that they're relatively new to your area, so the demand is outstripping supply of installers who have been doing this for 30+ years and as such are charging to that effect.

SomaticPirate 3y ago

For most single family US homes (which are single story) this would likely be a nightmare to install and maintain. Definitely a cool idea but a leak or any maintenance might quickly undercut the cost savings

PaulDavisThe1st 3y ago
Just as an FYI: > Information obtained from the US Census Bureau’s Survey of Construction (SOC) and tabulated by NAHB, shows that the rising trend of single-story homes reversed in 2021. The share of single-story homes decreased in 2021 and the share of two or more stories homes started was greater than one story homes. This is in line with recent NAHB analysis of new single-family home size trends. https://eyeonhousing.org/2022/07/share-of-two-or-more-stories-new-homes-increased-in-2021/ https://eyeonhousing.org/2022/07/share-of-two-or-more-storie...
sgerenser 3y ago
Shouldn’t be a problem in any home (1 story or 2) with a basement or taller crawlspace, which is a significant fraction of U.S. homes.

Wohlf 3y ago

Speaking of heat pumps and water heat, I installed both a heat pump and hybrid water heater to save on electricity. The water heater doesn't seem to have made much of a difference in my electrical bill, my guess is the problem is peak demand so I should have gotten a much bigger tank than before. Ambient garage temperature may also be an issue but it exhausts outside and the garage is insulated so it generally stays above 55 degrees.

cogman10 3y ago
Make sure you are in energy saving mode. The default for these systems is to try and do quick recovery which likely isn't what you want.
bluGill 3y ago
While those save money, most people don't really use a lot of hot water and so the amount they can save is limited.
alostpuppy 3y ago
Ah. I installed one in a uninsulated garage and it was really a big savings. It’s basically a free ac for whatever space it’s installed in

uconnectlol 3y ago

they also aren't very hot and wont work in northern cities, but people will install them there anyway. "boiler" - is that jargon for multiple kinds of heating units or actually just boilers?

twic 3y ago
By boiler i mean the big box on the wall in the kitchen which burns natural gas to heat water. This may be a UK specific usage.
- foresto 3y ago
  I think this is known as a tankless water heater in the US. (Tankless because you said it's on the wall.)
  - komadori 3y ago
    Boilers in the UK are usually mounted on the inside of an exterior wall to provide for venting exhaust gases outside. They may provide hot water on-demand without a tank (combi boiler) or fill a hot water cylinder on a schedule (system boiler) depending on type. Heating is typically provided by the boiler pumping hot water through a circuit of wall-mounted radiators regulated by TRVs (Thermostatic Radiator Valves).
- sgerenser 3y ago
  Boilers are definitely much more common in the UK than US. I believe New England is one of the few areas of the US that has a relatively high percentage of homes with hydronic+boiler heating setups. In most other parts of the U.S., many people probably have no idea what a boiler even is.
  - mattpallissard 3y ago
    Pretty common in the Northwest part of the country as well.
3y ago

cogman10 3y ago

> But fitting one is a big deal - they are quite expensive, they take a lot of work to fit, really require extensive additional insulation I think this somewhat overblows the complexity of a heat pump. They are simply Air conditioners that can be ran in reverse. One valve is the difference between a heat pump and AC. Why they are so expensive is really just price gouging because they aren't as common. If you are in a home with forced air AC then installing a heatpump system couldn't be simpler and should be something you consider when updating your AC system. It's really just a matter of updating the compressor and maybe adding some smarts to avoid condensation. In fact, it's shocking to me that AC -> heatpump conversion kits haven't hit the market. > So i'm slightly mystified that we basically don't hear anything about fitting drainwater heat recovery [1], in which the lukewarm drain water from your shower is used to pre-warm the incoming cold water. It's extremely simple, pretty cheap, simple to fit, and can recover ~50% of the waste heat, of something which is tens of percent of the energy consumption of a household. Really interesting idea, but I assume you have to rip up the shower to accomplish this right? Also, I'm guessing clogged wastewater piping might be an issue right? That said, that'd be easily overcome by just running the lines side by side with maybe a simple copper connector for heat exchange.

bluGill 3y ago
What is mystifying to me is why governments allow air conditioners without that reversing valve to be installed. A simple change, and the more people installing a heat pump the cheaper those valves get.
- ianburrell 3y ago
  I regret getting just an AC a while ago. I could have gotten a heat pump and used it for most of the heating. Even if I didn't get heat pump installed, one that could have been converted to heat pump without complete replacement would been nice.
computerdork 3y ago
Agree with your take. Recently helped install a heat pump at a single-family home (rental property) in the SF Bay Area. Actually, they aren't that much more expensive than AC's (mine cost about $9k for everything, but again, I did 35% of the work myself for a ducted 3 ton heat pump). And yeah, the installation is almost exactly the same as what you'd do for an AC. And, you don't need to add insulation, but we did (to the crawlspace), costing about $2.5k And, it's been running for about 3 months, and saved about ~$175/month in heating. wow. It'll pay for itself in about 7-8 years.

deleted 3y ago

[deleted]