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Heat Pumps – The Well-Tempered Future of A/Cs

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Re: Heat Pumps – The Well-Tempered Future of A/Cs

#131
post #128
post #48

Earlier quoted context omitted.

Although natural gas is "clean" compared to, say, coal, the advantage of a heat pump is that it uses less total energy than natural gas. That means it would be more efficient to run a heat pump off a natural gas power plant than to burn natural gas to heat your home directly.

People's AC summertime electric bills regularly get into triple-digits - it's not uncommon to hear someone with a moderately sized home having a $200-400 electric bill in the summertime. However, even in the midst of winter, gas heating bills rarely climb above $100 monthly. What am I missing here? It seems a heatpump, while more efficient, will cost significantly more to operate. Natural Gas is cheap ... and clean e…

It's actually difficult to say what the cost would be if everyone switched over. The reason is that natural gas is subsidized, both on the production side (at least in the US, which wants energy security) and on the consumption side (because it's politically unpopular to let people freeze to death). Of course, electricity prices are also affected by subsidies. Figuring out the true operating prices would require some research. However, it remains true that, in terms of greenhouse gas emissions, it is usually preferable to heat a home with a heat pump than by burning gas directly (there exists a temperature below which any given unit will become less efficient than burning gas, but unless you live in a place where this temperature is common then heat pumps will still come out on top (and the fact that residential gas lines are notoriously leaky and basically just venting nonstop into the atmosphere makes the calculation even more favorable)).

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#132

My 20 year old air conditioner recently died and I was looking into replacements. In my climate the temperature ranges from 40C in the summer, and -40C in the winter. After doing some research, it seemed pretty clear that having a furnace+AC was the way to go for my climate. Hardly a magic bullet technology.

-40C? That's an extreme situation. Heat pumps can be installed with backup heating as I understand it.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#133

Earlier quoted context omitted.

This persistent myth just needs to go away. People use heat pumps all over Scandinavia, including in the arctic circle. They are extremely popular there. They were early adopters of this technology there decades ago. There are two popular varieties: - Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or where…

The myth exists because the US is probably 10-20 years behind Europe and China in terms of HVAC and insulation technology. I recently had some reasonably high efficiency heat pumps installed at my house, and I’ve been very unhappy with the low temperature performance. It doesn’t even get very cold here—rarely below 5F (-15C) and a record low of -8F (-22C). The heat pumps I got (recommended by the well-regarded local…

Can't you get backup heating in addition to a heat pump for the coldest days?

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#134

Earlier quoted context omitted.

This persistent myth just needs to go away. People use heat pumps all over Scandinavia, including in the arctic circle. They are extremely popular there. They were early adopters of this technology there decades ago. There are two popular varieties: - Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or where…

I've been on zoom calls with two separate co-workers who are all bundled up because their heat pump can't handle the weather. It doesn't mean that the technology is inadequate in principle--probably their systems have some problem that competent HVAC installers know how to avoid. But its an unfortunate fact that there are places in the US where installers that recommend heat pumps can't be found for 100 miles. It doe…

Properly designed heat pump system includes backup for the coldest days - usually direct electric heating.

Most houses in Finland have a (decent) fireplace for heating in case of an electric outage.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#135
post #131
post #128

Earlier quoted context omitted.

People's AC summertime electric bills regularly get into triple-digits - it's not uncommon to hear someone with a moderately sized home having a $200-400 electric bill in the summertime. However, even in the midst of winter, gas heating bills rarely climb above $100 monthly. What am I missing here? It seems a heatpump, while more efficient, will cost significantly more to operate. Natural Gas is cheap ... and clean e…

It's actually difficult to say what the cost would be if everyone switched over. The reason is that natural gas is subsidized, both on the production side (at least in the US, which wants energy security) and on the consumption side (because it's politically unpopular to let people freeze to death). Of course, electricity prices are also affected by subsidies. Figuring out the true operating prices would require some…

It seems to me, there is no future where a heatpump can be the only source of in-home heating then.

1) Natural Gas is vastly cheaper in most/all of the US.

2) Homes still require an alternative heating source when temperatures drop to low levels (coincidentally when people need heating the most).

So, even if a heatpump is technically more efficient in terms of emissions, the technology does not solve all of the problems it's attempting to replace. Additionally, Natural Gas is vastly more clean in terms of emissions than some other alternatives still used around the country.

There's no way the average home is going to stomach 2-4x more heating expenses on average without some real tangible benefit (hand-wavy emissions numbers don't factor into the average homeowner's decision making).

I must be missing something here...

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#136
post #3

Isnt any a/c a heat pump though?

I think the media has once again assigned a term their specific definition and created a meme out of it. I guess it makes sense if you have no preconceived notions of what a "heat pump" is. But yes, to anybody that knows an air conditioner is a type of heat pump, these articles read akin to "Personal cars create too many emissions. Companies have come up with an innovative way to reduce this problem: vehicles ". (wit…

It’s not the media doing this; “heat pump” has been industry lingo (in the US at least) for an A/C with a reversing value since at least the early 1980s.

My parent’s house had a heat pump then and does so today (albeit much improved over the decades).

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#137

My 20 year old air conditioner recently died and I was looking into replacements. In my climate the temperature ranges from 40C in the summer, and -40C in the winter. After doing some research, it seemed pretty clear that having a furnace+AC was the way to go for my climate. Hardly a magic bullet technology.

-40C? That's an extreme situation. Heat pumps can be installed with backup heating as I understand it.

> Heat pumps can be installed with backup heating as I understand it.

Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#138
post #137

Earlier quoted context omitted.

-40C? That's an extreme situation. Heat pumps can be installed with backup heating as I understand it.

> Heat pumps can be installed with backup heating as I understand it. Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.

> Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.

A) Not everywhere

B) Heat pumps can be powered with solar, reducing costs even if your gas would normally be cheaper

C) Some people are willing to spend a little more if it helps push electrification forward, for environmental reasons

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#139

Earlier quoted context omitted.

Yes, but typically “heat pump” is used to mean it can provide heating too, whereas standard “A/C” is a “one-way” heat pump that only provides cooling.

I always went with this description too, though oddly a "heat pump water heater" only works one direction, yet "heat pump" is still in its name.

Perhaps think of "heat pump" as something that can (also) bring heat into a building, whereas A/C generally (only) removes heat from it.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#140
post #81

Earlier quoted context omitted.

Walk around in the American Heating and Refrigeration conference for a while to get a feel of these trends, this was specifically called out by many manufacturers as driven by the green movement.

It's being driven by government pressure to reduce energy consumption and dependence on fuel imports. That isn't a bad thing. It's the sort of thing a responsible government should be planning for.

Natural gas is available in abundance, is nearly free in terms of cost, and is vastly more "green" than many alternatives available today.

It may not be as green as pure electric can be in theory, but in large portions of this country electric isn't all that green either.

Heat pumps appear expensive to operate. Imagine running your AC year-round... that very thought makes many-a-homeowner shudder.

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