Heat is low-density and it's difficult to work with. And fossil fuels are extremely high-density and easy to work with. So when heat is needed, the general approach has been to burn fossil fuels locally and just dump the waste heat. This has not properly accounted for the cost of fossil fuels.
Low-intensity waste heat is valuable. And it is something that can be captured and used. But that is a different kind of mentality, and a different kind of engineering, one that hasn't been much-developed. For example, here in Canada, like in many countries, we like to take hot showers. We take hot showers even in winter, and there can be an 80 °C difference between the water flowing down the drain and the air outside. Is there no further useful work that heat could do?
In BC and Ontario (and I believe other places too) the building code includes passive heat capture for drains for new builds. You can recover quite a bit of the heat for very little money.
These sorts of technologies tend to be very region and building dependent. They add complexity for some amount of energy recapture, but often the energy recapture isn’t worth it, or some other optimization would have a better pay off. (If we were talking about software, the law would be similar to “all floating point must be done in unrolled assembly loops”, which sounds reasonable but breaks GPUs, instruction cache, interpreters, etc).
For example, we didn’t insulate our concrete slab floor because our windows provide too much passive heat 10 months out of the year. We’re on the edge of the region where such insulation is recommended (thankfully, it is not required here - in the fall, we have to run the air conditioning when it is in the mid sixties outside! In the summer, we don’t need A/C until the upper seventies because of the angle of the sun and passive cooling from the slab).
Anyway, our hybrid hot water heat pump has a COP of two or three, and was a much cheaper upgrade than passive heat reclamation would have been.
Because we bought an efficient unit, it uses hardly any power (800kwh per year, so an average of 91 watts, or about $100/year, or charging my car from empty to full 24 times), so we’d be better off with some other upgrade on a thing that hasn’t hit diminishing returns.
For instance, we should have used bigger air ducts on our hvac system to improve the air handler’s efficiency.
I am immediately on the side of the owner-builder, but then
> in the fall, we have to run the air conditioning when it is in the mid sixties outside!
what? building design has a lot of parts to it.. "big cement slab" and "some insulation" are not the only parts.. But good quality design and the parts to build it are expensive. There is an underlying theme of saving money to accomplish something otherwise not possible. I am sympathetic to that of course.. Something is not right about the design, but what bad manners to point it out first! Someone put a lot of effort into some upgrade and they likely cannot change the decisions they made, due to time and costs, etc.
good to hear the details and mostly supportive here -- green building has got to get better, starting yesterday IMHO
The problem is that it is sunny in that month. Historically around here, we’d have more cloud cover, and it would be tuned right. The plan was to open the windows if this was a problem, but we’re also getting more flies / biting flies than before during those months.
Of course, the excess sun means excess solar production when most people aren’t running heaters or A/C.
The expensive fix is to increase the amount the roof sticks out by a foot or so to block the sun for an additional month in fall and spring.
The cheap fix (what we are going for) is to put up curtains or blinds that let us manually tune the amount of passive heating we get from the sun.
Either fix would also reduce glare, but only the curtains let us tune the pre/post solstice passive heating. It is colder post-solstice for a given angle of sun, so extending the roof enough for November probably implies paying more for heat in Jan/Feb.
Do your windows not have screens? That would allow you to have the windows open even when there's flies. Now if you have bad air pollution/smells (smoke, livestock, city) then screens won't help.
I’d love to hear more about your design, and retrospective on the decisions. We are about to undertake a design for a new build and energy efficiency using passive technologies is something that matters to us.
We had been planning a highly insulated slab with exposed concrete floors, but your comments on having to run AC seems concerning if I am reading it right. We plan for awnings to keep sun off the windows in the high summer sun.
We went all electric in an area where PG&E outages are frequent. We have battery and solar, but during extended outages there usually isn’t any sun. Our solution is to get a propane tank and generator that can charge the battery. This is a complicated compatibility problem, so we should have put the generator in at the same time as the battery and solar.
Heat pumps are fine, but the contractor undersized the ducts. Run a system backpressure test yourself (get the service manual) before writing the final check for the install.
Permitting and insurance in California are maliciously bad.
If you want a graywater system, apply for the permit at the same time you start the project. Also, be prepared to pay $20-30K for “engineering” and permits, but only $1-5K for parts and installation. (Or look around more than we did for an ethical designer.)
Get the best possible insulation and if possible pay for plaster. We’ve had a few leaks, and plaster / rockwool is much more tolerant of water than drywall / fiberglass.
Pay for all the smarthome stuff, but insist on offline home assistant compatibility.
Wire multiple outdoor circuits (120v and 240, if possible) so you can charge a car, run a hot tub, run a pool pump, charge a lawnmower, etc, etc without thinking about circuit capacity. You won’t do those things, but they cost basically nothing now, and $10K or more later.
AFCI breakers are a scam (incompatible with appliances that contain motors or switches), so expect nuisance trips unless you replace them with GFCI post-inspection.
The fancier the lamp, the more compatibility and capacitor whine you will encounter. Our most trouble free lamps were under $100 at ikea. I know which ones cost 10x that, but meh.
Under no circumstances purchase doorknobs made by emtek, assa abloy or kwikset. (Two of those brands are $$$).
Keep a bottle of spray air on hand at all times because modern smoke detectors will go off at 2am and the only way to fix it (other than a hatchet) is by spraying off the sensors.
Whatever your plan is for a roof, get a nicer one.
Pick a general contractor that has put up lots of homes in your county.
Oh, and either find someone that has installed like 100 hybrid hot water heaters, or check the installation for wires that rub (heat pumps usually don’t vibrate) and air exhaust / inlet condensation post-install.
One other thing. If the house is passively cooled and heated, you will want to leave the windows open when you are not home. European style tilt and turn windows are perfect for this, since they are secure when open in tilt mode:
In winter climates it’s extremely common to run humidifiers to add water to the air. Using a bathtub for the same purpose is pretty common and I’ve never heard of either causing mold in normal operations.
These days there's heat recovery drains. The idea is generally to first make sure you use a thermostatic tap for the shower and then use the drain water to heat the cold water line going to the tap. The thermostatic tap will adjust to keep water temperature steady as the incoming "cold" water gets warmer over time.
The marketing material claims energy savings of up to 50%, but presumably you'll only reach that amount of savings if you take hour long showers at ridiculous temperatures.
I'm more in agreement with the likes of BedJet. When possible (i.e. when in a bed), we should be hearing humans and not the environment that they inhabit. I greatly enjoyed mine, it was like sleeping in a cloud - unfortunately my wife didn't and it went to good will.
I replaced my gas heating with a heat pump and ground loop last year.
Removed my water heater and HVAC, for two 500 feet deep holes in the ground. Electricity bill is low, and gas bill is gone. You can receive tax breaks from federal, state, and local utility companies (in the US) too.
While I do recommend it, you may need to wait for an available drill if the terrain under your property is difficult to dig through.
Excluding all the bells and whistles, as well as the incentives. The ground loop and heat pump package comes to $48k.
However, I paid significantly less than that even with all of the additions. As the incentives and discounts reduced it by about ~14k. The tax credits are ~13.5k, which won’t be realized until this upcoming tax season.
This is where I need to be eventually. I'm hesitant because I'm worried that I won't find any competent installers in my area and I'll end up with leaks, polluted well water, etc... Any troubles with the ground loop so far?
No issues whatsoever with the ground loops. They will supposedly outlive the lifetime of the home according to the installer (~120 years).
Only issue I’ve had at all is with the thermostat, which is an Ecobee Pro. While these smart thermostats are okay, they seem to mess up some of the more basic requirements of a thermostat, compared to the older dumb models.
For context, the system went live in January, all permits cleared in November. So about a year of use.
Never had I thought that, of all things, heat pumps would be the ones to bring the right-wing to power back again in Germany, but here we are.
Interesting that the author of the article doesn't mention the AfD at all, or politics, for that matter, his world is this techno-utopia where we're told what "the future is" and we, the masses, should blindly follow. Very dangerous game to play.
What does heat pumps have to do with the AfD? To me (a western neighbor) they stand for racism and hysterically dubious fiscal policies combined with voodoo economics. That could just be reporting though. But then again we have our own version of that as well.
The AFD is just attacking everything that the Greens propose. No constructive discussions at all, only populism. I fear that heat pumps will be the smaller „issue“ society will face in near future. The citizens are not yet ready for the necessary changes. Another problem is that Russia is trying to heat things up, too, not with the gas they provided, but with fake news campaigns in various medias. And yes, insulation is more important than the heating—-it can cut 80 percent of the bill for heating.
Replaced my 17 year old HVAC system that died this year with a heat pump for both heating and cooling last month and am excited to see the savings.
Also replaced our just as old non-working shutters with dual cellular blinds for additional insulation.
One thing I do slightly regret is although Trane / American Standard (they're the same company) is highly rated (according to Consumer Reports) for reliability, if you use a variable speed heat pump and air handler, they use a custom communication protocol (digital instead of analog) that no modern third party thermostats use it, and you have to use Trane thermostats instead.
So far the Trane app works well for manipulating temperature, setting a schedule and holding it like 3rd party hardware and apps, but you're not going to get like HomeKit integration if that's a thing you care about.
I have that exact setup for control, and there’s 1 thing I want to control, and that’s the start time of warming up in the morning depending on outside temp. It’s less efficient at lower temps so takes longer to provide enough heat, and my house loses heat faster at cooler temps, so needs more heat at those lower temps. I want to say “make it 72 at 8am” not “start at 6am to try to get to 72 at some future time”
I’m also concerned about what happens when their online system stops working. Technically I can program some on the connected unit, but it’s not ideal
Oh, it also can only use the temp from 1 remote thermostat at a time. My last 3rd party one allowed, for instance, the night temp to be the remote in the bedroom and the daytime to be set by the living room remote - Trane doesn’t support that in the schedules at all.
I did look into that, but it means installing another app from what I've read (meaning I'd be just switching from the Trane to the Home Assistant one). If it allows me to control the thermostat from Apple Home, I'd be for it.
Once you get Home Assistant to control your thermostat, you can add the excellent HomeKit integration to HA. That exposes all or some of your devices in HA to Apple Home. You can then access them like other Apple Home devices, including via Siri if that’s interesting to you. It’s great.
When I try to use reader mode on Firefox I get the following. The URL at the end does not resolve. Any idea what this is?
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I’m always so confused when I read about heat pumps online. In Australia we’ve had heat pump based air conditioning for like decades as far as I understand. Using them to cool indoor spaces is almost essential given how hot it gets in some parts of Australia. However I’ve never come across such a system that isn’t what we call a reverse cycle aircon, that is, it can also heat an indoor space. We do have evaporative coolers in places that experience dry heat, those cannot work in reverse of course, but they are not heat pumps either.
What confuses me is that, I could understand if this is uniquely an Australian experience to have this in your home, office and shops, but don’t all modern cars have heat pump air conditioners? They usually don’t reverse to heat the inside space, the car instead just dumps the engine’s heat into the interior space and/or uses resistive heating, but still the technology is exactly the same! It’s just missing one component and configuration that makes it reversible.
Maybe I’m way wrong and it’s a completely different thing but idk
There are parts of the US that widely use your standard heat pump such as Florida. Here in the Midwest most single family homes use central air which is a combination of an outdoor air conditioner unit and a natural gas furnace. Heat pumps are a topic here because the natural gas furnace is just so prevalent.
There was a lot of lobbying by the natural gas companies in the 80's, so there's a pretty significant group of people that write off heat pumps not realizing that yes, fridges, freezers, air conditioners are all single-direction heat pumps.
> The first mini-split systems were sold in 1954–1968 by Mitsubishi Electric and Toshiba in Japan,
- Wikipedia
Carrier and friends were already getting huge by this time in North America, and we were still decades away from any Asian imports being seen as anything more than bottom of the barrel goods.
The shittiest VCR you could buy at Best Buy in the early 1990’s in the US was produced by Goldstar, a Korean manufacturer, which today sells some of the very most expensive home electronics options. A change like that calls for a rebranding, which is why you and I know the company by a different name: LG.
Australia seems to have a more direct line to Asian manufacturers, particularly before shipping improved, so it’s not surprising you all ended up with mini splits. Also old American cooling loops are bulky, making them less efficient to ship that far.
42 comments
[ 3.6 ms ] story [ 89.4 ms ] threadLow-intensity waste heat is valuable. And it is something that can be captured and used. But that is a different kind of mentality, and a different kind of engineering, one that hasn't been much-developed. For example, here in Canada, like in many countries, we like to take hot showers. We take hot showers even in winter, and there can be an 80 °C difference between the water flowing down the drain and the air outside. Is there no further useful work that heat could do?
For example, we didn’t insulate our concrete slab floor because our windows provide too much passive heat 10 months out of the year. We’re on the edge of the region where such insulation is recommended (thankfully, it is not required here - in the fall, we have to run the air conditioning when it is in the mid sixties outside! In the summer, we don’t need A/C until the upper seventies because of the angle of the sun and passive cooling from the slab).
Anyway, our hybrid hot water heat pump has a COP of two or three, and was a much cheaper upgrade than passive heat reclamation would have been.
Because we bought an efficient unit, it uses hardly any power (800kwh per year, so an average of 91 watts, or about $100/year, or charging my car from empty to full 24 times), so we’d be better off with some other upgrade on a thing that hasn’t hit diminishing returns.
For instance, we should have used bigger air ducts on our hvac system to improve the air handler’s efficiency.
I am immediately on the side of the owner-builder, but then
> in the fall, we have to run the air conditioning when it is in the mid sixties outside!
what? building design has a lot of parts to it.. "big cement slab" and "some insulation" are not the only parts.. But good quality design and the parts to build it are expensive. There is an underlying theme of saving money to accomplish something otherwise not possible. I am sympathetic to that of course.. Something is not right about the design, but what bad manners to point it out first! Someone put a lot of effort into some upgrade and they likely cannot change the decisions they made, due to time and costs, etc.
good to hear the details and mostly supportive here -- green building has got to get better, starting yesterday IMHO
Of course, the excess sun means excess solar production when most people aren’t running heaters or A/C.
The expensive fix is to increase the amount the roof sticks out by a foot or so to block the sun for an additional month in fall and spring.
The cheap fix (what we are going for) is to put up curtains or blinds that let us manually tune the amount of passive heating we get from the sun.
Either fix would also reduce glare, but only the curtains let us tune the pre/post solstice passive heating. It is colder post-solstice for a given angle of sun, so extending the roof enough for November probably implies paying more for heat in Jan/Feb.
We had been planning a highly insulated slab with exposed concrete floors, but your comments on having to run AC seems concerning if I am reading it right. We plan for awnings to keep sun off the windows in the high summer sun.
We went all electric in an area where PG&E outages are frequent. We have battery and solar, but during extended outages there usually isn’t any sun. Our solution is to get a propane tank and generator that can charge the battery. This is a complicated compatibility problem, so we should have put the generator in at the same time as the battery and solar.
Heat pumps are fine, but the contractor undersized the ducts. Run a system backpressure test yourself (get the service manual) before writing the final check for the install.
Permitting and insurance in California are maliciously bad.
If you want a graywater system, apply for the permit at the same time you start the project. Also, be prepared to pay $20-30K for “engineering” and permits, but only $1-5K for parts and installation. (Or look around more than we did for an ethical designer.)
Get the best possible insulation and if possible pay for plaster. We’ve had a few leaks, and plaster / rockwool is much more tolerant of water than drywall / fiberglass.
Pay for all the smarthome stuff, but insist on offline home assistant compatibility.
Wire multiple outdoor circuits (120v and 240, if possible) so you can charge a car, run a hot tub, run a pool pump, charge a lawnmower, etc, etc without thinking about circuit capacity. You won’t do those things, but they cost basically nothing now, and $10K or more later.
AFCI breakers are a scam (incompatible with appliances that contain motors or switches), so expect nuisance trips unless you replace them with GFCI post-inspection.
The fancier the lamp, the more compatibility and capacitor whine you will encounter. Our most trouble free lamps were under $100 at ikea. I know which ones cost 10x that, but meh.
Under no circumstances purchase doorknobs made by emtek, assa abloy or kwikset. (Two of those brands are $$$).
Keep a bottle of spray air on hand at all times because modern smoke detectors will go off at 2am and the only way to fix it (other than a hatchet) is by spraying off the sensors.
Whatever your plan is for a roof, get a nicer one.
Pick a general contractor that has put up lots of homes in your county.
https://www.vetrinawindows.com/styles/tilt-and-turn-windows
(I’ve never heard of that brand, but their webpage has a nice animation explaining the product.)
I paid to heat that water up, so I damn well want to get as much out of it as I can.
If I took baths every day then it might become a problem but once a week or so had had no negative effects.
The marketing material claims energy savings of up to 50%, but presumably you'll only reach that amount of savings if you take hour long showers at ridiculous temperatures.
Removed my water heater and HVAC, for two 500 feet deep holes in the ground. Electricity bill is low, and gas bill is gone. You can receive tax breaks from federal, state, and local utility companies (in the US) too.
While I do recommend it, you may need to wait for an available drill if the terrain under your property is difficult to dig through.
Do you know temperature at that dept?
Temp is 52f from our loops. Supposedly very consistent once below the frost line (6ft or so). All depends on the region you are in.
However, I paid significantly less than that even with all of the additions. As the incentives and discounts reduced it by about ~14k. The tax credits are ~13.5k, which won’t be realized until this upcoming tax season.
Only issue I’ve had at all is with the thermostat, which is an Ecobee Pro. While these smart thermostats are okay, they seem to mess up some of the more basic requirements of a thermostat, compared to the older dumb models.
For context, the system went live in January, all permits cleared in November. So about a year of use.
Interesting that the author of the article doesn't mention the AfD at all, or politics, for that matter, his world is this techno-utopia where we're told what "the future is" and we, the masses, should blindly follow. Very dangerous game to play.
Also replaced our just as old non-working shutters with dual cellular blinds for additional insulation.
One thing I do slightly regret is although Trane / American Standard (they're the same company) is highly rated (according to Consumer Reports) for reliability, if you use a variable speed heat pump and air handler, they use a custom communication protocol (digital instead of analog) that no modern third party thermostats use it, and you have to use Trane thermostats instead.
So far the Trane app works well for manipulating temperature, setting a schedule and holding it like 3rd party hardware and apps, but you're not going to get like HomeKit integration if that's a thing you care about.
I’m also concerned about what happens when their online system stops working. Technically I can program some on the connected unit, but it’s not ideal
Oh, it also can only use the temp from 1 remote thermostat at a time. My last 3rd party one allowed, for instance, the night temp to be the remote in the bedroom and the daytime to be set by the living room remote - Trane doesn’t support that in the schedules at all.
https://www.home-assistant.io/integrations/nexia/
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What confuses me is that, I could understand if this is uniquely an Australian experience to have this in your home, office and shops, but don’t all modern cars have heat pump air conditioners? They usually don’t reverse to heat the inside space, the car instead just dumps the engine’s heat into the interior space and/or uses resistive heating, but still the technology is exactly the same! It’s just missing one component and configuration that makes it reversible.
Maybe I’m way wrong and it’s a completely different thing but idk
Do you guys have… fridges? Freezers?
There was a lot of lobbying by the natural gas companies in the 80's, so there's a pretty significant group of people that write off heat pumps not realizing that yes, fridges, freezers, air conditioners are all single-direction heat pumps.
- Wikipedia
Carrier and friends were already getting huge by this time in North America, and we were still decades away from any Asian imports being seen as anything more than bottom of the barrel goods.
The shittiest VCR you could buy at Best Buy in the early 1990’s in the US was produced by Goldstar, a Korean manufacturer, which today sells some of the very most expensive home electronics options. A change like that calls for a rebranding, which is why you and I know the company by a different name: LG.
Australia seems to have a more direct line to Asian manufacturers, particularly before shipping improved, so it’s not surprising you all ended up with mini splits. Also old American cooling loops are bulky, making them less efficient to ship that far.
They never used it as gas heating was cheaper to run back then.
Previously electricity and gas was so cheap it wasn't worth the cost of a heat pump, now its worth considering even for things like clothes dryers.