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How a heat pump works

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Re: How a heat pump works

#181

Post by triceratops »

thekingshorses wrote: post #171
achenatx wrote: post #96

Earlier quoted context omitted.

my friend is building his house and is putting in 4 heat pumps (big house). The problem is we just lost power for 4 days and 2 years ago we lost power for 5 days. He is discovering that electric heat uses massive amounts of electricity and there is no way to get a residential generator big enough to power them all. He might not even be able to power one (they can use in excess of 20kw). I would never get electrical w…

If there is a power outage, you can't run your natural gas heater either. It needs fan to run.

But you can run a furnace fan off a diesel generator.

Re: How a heat pump works

#182

Post by nicoburns »

nashashmi wrote: post #111
gabrielhidasy wrote: post #65

Earlier quoted context omitted.

They literally are more efficient than burning gas, a good heat pump can do over 300% efficiency (KWs of heat in your house vs KWs of electricity used) while a furnace can only hope to get 100%. Even if the heat pump is fed from gas power plants (which burn gas with about 50-60% efficiency, more if the waste heat is reused), they are still using less gas for the same amount of heat than directly burning it.

400% efficiency? Is that even possible? (Did AI write this?)

If you measure the efficiency of heat output relative to the electrical input power, then yes. The trick is that there's actually another input: latent heat in the environment. But given that this is abundant and freely available we don't usually bother to include that in our calculations.

Re: How a heat pump works

#183

Post by micromacrofoot »

redeeman wrote: post #44
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

topic of discussion: is anyone else concerned that all the new things being clearly pushed hard, regardless of reasons(good or bad), has the common theme of centralizing. In a world where if your heatpump stops working, you die from cold, it would be an awfully sad thing if social credit scores dictated a very low kilowatthour limit. Much more sad than a world where you obtain firewood from some local vendor

They could also just shut off your gas, heat pumps introduce no newfound ability to be authoritarian that isn't already there.

Re: How a heat pump works

#184

Post by nicpottier »

peterhunt wrote: post #180
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

It is coordinated. In many states there are huge incentives [1] to disconnect your existing home from (and not connect new construction to) the natural gas infrastructure. This is great for the climate but air source heat pump technology simply doesn't work well in cold climates. Most heat pumps in the United States have 100% efficiency down to about 20 degrees F. Below that they "lose efficiency." What most people d…

This is FUD. I live in climate zone 5 in a 100 year old house that has high heating demands and our air source heat pump has been awesome, even when it dipped into the negatives briefly this year. Our heat pump is over 100% efficient down to 0F.

Re: How a heat pump works

#185

Post by triceratops »

redeeman wrote: post #44
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

topic of discussion: is anyone else concerned that all the new things being clearly pushed hard, regardless of reasons(good or bad), has the common theme of centralizing. In a world where if your heatpump stops working, you die from cold, it would be an awfully sad thing if social credit scores dictated a very low kilowatthour limit. Much more sad than a world where you obtain firewood from some local vendor

Did you know that installing a heat pump doesn't magically cause fireplaces in the house to stop working? Or that if you're concerned about being cut off from electricity because of your low "social credit score" the heat pump will run just fine off solar panels and batteries?

Re: How a heat pump works

#186

Post by LazyMans »

mikeyouse wrote: post #167
LazyMans wrote: post #54

Earlier quoted context omitted.

This guy is a great resource if you want to understand what goes into a proper A2W system install. In Europe, it seems by law they are required to do heat loss calculations to size an install. In the US, it seems to be a little more loose. https://www.youtube.com/watch?v=0IvGe4JZLSU

I saw a video recently from a ... less sophisticated place in the US... where the HVAC installer literally held up a piece of paper from the street with different sized houses on it, and sized the HVAC based on which of the houses best "covered up" the actual house when looking through the semi-transparent paper. Just astonishing. No consideration at all for the build quality/insulation details, no adjusting for the…

That's insane. Proper sizing is paramount, it's also a good way to surface that 5k in insulation improvements might be the better first step to consider vs installing a larger system just to keep up with losses.

Re: How a heat pump works

#187

Post by boringg »

Oh I have a question for the community here about heat pumps. I have three mini splits that I use for AC but connecting them to a home hub is bananas amount of work and inconsistent (Mitsubishi brand). I wish there was a legitimately good, robust system to connect AC units to my smart thermostat (Ecobee) or even some of the other devices I have.

It still feels the wild west for home energy systems - and the costs are quite high for the value they provide.

Re: How a heat pump works

#188

Post by kodt »

boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

1. There was recently a statement released by a member of the Consumer Product Safety Commission saying they were considering regulating indoor pollution from natural gas stoves. This lead to a bunch of outrage and claims that Natural Gas was going to be banned at a Federal level. https://www.washingtonpost.com/climate-environment/2023/01/1...

2. Cites like NYC have implemented bans or limits on new gas installations, and it has been proposed at the state level as well. Other cities such as Chicago have had conversations regarding this issue, at least enough for it to get into the news and spark minor outrage.

Because of these recent controversies there has been much talk about Heat Pumps and whether or not they are able to function efficiently or sufficiently in sub zero temperatures regularly seen in the upper Midwest or North East.

Re: How a heat pump works

#189

Post by billjings »

aaronbrethorst wrote: post #169
sophacles wrote: post #153

Earlier quoted context omitted.

What is IRA in this context? I don't think heat pumps have anything to do with retirement nor the political status of Norther Ireland.

The inflation reduction act of 2022. https://www.hvac.com/resources/inflation-reduction-act-heat-...

Yep, the Inflation Reduction Act is what I meant. It came into effect this year.

Re: How a heat pump works

#190

Post by kortilla »

nashashmi wrote: post #111
gabrielhidasy wrote: post #65

Earlier quoted context omitted.

They literally are more efficient than burning gas, a good heat pump can do over 300% efficiency (KWs of heat in your house vs KWs of electricity used) while a furnace can only hope to get 100%. Even if the heat pump is fed from gas power plants (which burn gas with about 50-60% efficiency, more if the waste heat is reused), they are still using less gas for the same amount of heat than directly burning it.

400% efficiency? Is that even possible? (Did AI write this?)

Yes, because a heat pump is taking the heat from the outside environment and moving it into your house. You’re only paying the “transportation cost” and not the actual cost to generate heat. The heat was generated by the sun.
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