Can Heat Pumps Change Demand for Air Conditioners Into a Climate-Change Win? (nytimes.com) 361
The New York Times reports:
As global warming fuels deadly heat waves across the country, more Americans in places like the Pacific Northwest are rushing out to buy air-conditioners for the first time. One common concern is that a surge in air-conditioning could make the planet even hotter, by increasing the need for electricity from power plants running on coal or gas, which produce emissions that drive global warming.
But some energy experts, as well as cities like Denver and Berkeley, California, have recently started exploring a counterintuitive strategy: Soaring demand for air-conditioning might actually be a prime opportunity to reduce fossil fuel emissions and fight climate change. The idea is simple: If Americans are going to buy air-conditioners anyway, either for the first time or to replace older units, why not convince them to buy electric heat pumps instead? Although the name can be confusing, an electric heat pump is essentially an air-conditioner that is slightly modified so that it can run in two directions, cooling the home in the summer and providing heat in the winter. That extra heating function is the key to helping tackle climate change. During the cooler months, heat pumps could warm homes far more efficiently than the furnaces that run on fossil fuels or electric resistance heaters that most households currently use, which would cut down on carbon dioxide emissions. Existing furnaces would only need to be used as backup on the coldest days of the year, since many heat pumps work less efficiently in subzero temperatures.
Most manufacturers already offer heat pump versions of the air-conditioners they sell, but they're typically about $200 to $500 more expensive to make. So, the idea goes, policymakers would have to step in with subsidies or regulations to make adoption universal. But if done right, proponents say, households would see utility bills either drop or stay largely unchanged, and they would even enjoy a more comfortable heating experience.
The Times spoke to Nate Adams, a home performance consultant who proposed the idea in a recent paper written with experts at Harvard University CLASP, a nonprofit formerly known as the Collaborative Labeling and Appliance Standards Program advising governments on energy efficiency. "Working with energy modelers, Mr. Adams and his co-authors estimated that, if two-way heat pumps become the standard option when people installed new central air-conditioning, they would be in 44% of American homes by 2032, up from just 11% today. On average, those homes could cut their fossil fuel use during the colder months by at least one-third. And, as states move to clean up their electricity grids by adding more wind and solar power, the climate benefits from those electric heat pumps would increase..."
"Homes and offices account for 13 percent of the nation's annual greenhouse gas emissions, with much of that from oil or natural gas burned in furnaces, hot water heaters, ovens, stoves and dryers. While the United States has made major strides in reducing pollution from power plants, building emissions have barely budged since 2005."
But some energy experts, as well as cities like Denver and Berkeley, California, have recently started exploring a counterintuitive strategy: Soaring demand for air-conditioning might actually be a prime opportunity to reduce fossil fuel emissions and fight climate change. The idea is simple: If Americans are going to buy air-conditioners anyway, either for the first time or to replace older units, why not convince them to buy electric heat pumps instead? Although the name can be confusing, an electric heat pump is essentially an air-conditioner that is slightly modified so that it can run in two directions, cooling the home in the summer and providing heat in the winter. That extra heating function is the key to helping tackle climate change. During the cooler months, heat pumps could warm homes far more efficiently than the furnaces that run on fossil fuels or electric resistance heaters that most households currently use, which would cut down on carbon dioxide emissions. Existing furnaces would only need to be used as backup on the coldest days of the year, since many heat pumps work less efficiently in subzero temperatures.
Most manufacturers already offer heat pump versions of the air-conditioners they sell, but they're typically about $200 to $500 more expensive to make. So, the idea goes, policymakers would have to step in with subsidies or regulations to make adoption universal. But if done right, proponents say, households would see utility bills either drop or stay largely unchanged, and they would even enjoy a more comfortable heating experience.
The Times spoke to Nate Adams, a home performance consultant who proposed the idea in a recent paper written with experts at Harvard University CLASP, a nonprofit formerly known as the Collaborative Labeling and Appliance Standards Program advising governments on energy efficiency. "Working with energy modelers, Mr. Adams and his co-authors estimated that, if two-way heat pumps become the standard option when people installed new central air-conditioning, they would be in 44% of American homes by 2032, up from just 11% today. On average, those homes could cut their fossil fuel use during the colder months by at least one-third. And, as states move to clean up their electricity grids by adding more wind and solar power, the climate benefits from those electric heat pumps would increase..."
"Homes and offices account for 13 percent of the nation's annual greenhouse gas emissions, with much of that from oil or natural gas burned in furnaces, hot water heaters, ovens, stoves and dryers. While the United States has made major strides in reducing pollution from power plants, building emissions have barely budged since 2005."
PNW (Score:4, Insightful)
Just for those curious, here in the PNW especially with the massive heat wave we just had: we're 90%+ hydroelectric in this region. And the only reason that percentage is going DOWN is because of the massive expansion to wind power. Those "fears", at least in the referenced PNW, are total bullshit and trying to shame individual consumers, rather than having mass-polluting mega-corporations take responsibility for their mass-polluting.
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Same here in British Columbia, 98% hydroelectricity.
My well-insulated home is heated with electricity and I have a conventional air conditioner for hot summer days. If I can do better I'd like to know how. One size does not fit all.
...laura
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Re: PNW (Score:2)
Re:PNW (Score:5, Informative)
we're 90%+ hydroelectric in this region
Yes and no. Our electricity is 90%+ hydro. But many people heat with natural gas. And oil. And even coal. If you can get them to switch to electric heat pump away from fossil fuel heat by offering a/c as a 'free' extra, great. But that represents additional electric load. And we don't have a carbon based fuel problem. We have a distribution system capacity problem. We had quite a few outages during last week's heat wave just from the small amount of air conditioning load on our systems.
In the Pacific Northwest, residential circuits tended to peak during the winter. Which was OK because the overload rating could be stretched on equipment because dissipating losses is easier in cold weather. No more. Now circuits are starting to hit peak loads during hot weather. When keeping them cool is more difficult. Driving around, I'm shocked by the number of pole pigs (transformers) I see with blackened, scorched paint jobs due to them running far over design temperatures.
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One easy way to lower the cost of electric heat is by getting a heat pump. Their effective efficiency can be as high as 300%. A fraction as much energy to get the same amount of heat.
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And the only reason that percentage is going DOWN is because of the massive expansion to wind power.
Well, that and the fact that we've recently torn down a number of dams because of their environmental impact... and we're not building new ones.
I wish I could - the government does not let me! (Score:3, Interesting)
So here is the story of the government regulation gone wrong.
I live in a condo, built in 1970s. It has a space and an outlet designed for a certain form factor AC/heat pump, which was the "original equipment". That form factor is quite compact, smaller than most of those used in newer style condos (you'll see why in a minute).
Sometime in the late 90s government passed new efficiency standards. These standards, while certainly well meaning, made heat pumps somewhat more complicated. To achieve these higher efficiency standards, they generally need to have larger pumps, more coil and, generally, more "stuff". There was one company up until 10 years ago, that tried building heat pumps that complied with the new standard but fit in the existing form factor. Unfortunately, their devices weren't the most reliable (hard to put all the required components in a small box) and also didn't quite pass the government testing. So they were heavily fined by the EPA and, eventually, went out of business.
So, when the time came to replace the then 30 year old AC/heat pump, the previous owner had no option to get a heat pump and had to buy what is still available in that form factor - which is a plain old AC + electric "emergency heat" coils. When I moved in a number of years ago, I looked high and low for a heat pump option - but none are available, because none are good enough for the government's standards.
So, my condo in the winter (October - March) is heated with what is, essentially, a giant hair dryer (resistive heat in the forced air path). This is as inefficient as any heating system can get in principle. It's also extremely expensive for me (my winter heating electric bills are 2-3 times more than the AC bill in summer). I wish I could get a heat pump, but alas - the government made it impossible. They'd rather I burn a ton of electricity for plain heat than use a (slightly less than maximum but still orders of magnitude more efficient than resistive heat) heat pump.
So, I am pretty sure this will be another thing the government will fuck up just like they did before. Good luck.
Re:I wish I could - the government does not let me (Score:5, Insightful)
The owner could have just boarded up the holes and installed splits.
Being completely dependent on finding something which could fit a give size hole 50 years later would have had a huge chance of failure regardless of government interference, that's just the owner being inflexible.
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He is the owner.
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Oh, missed that. Let me rephrase then, that's the owner or the HOA being inflexible.
If the HOA isn't being a bunch of anal assholes, get a sawzall and widen the hole or if it's up not too high, replace with a split.
Re:I wish I could - the government does not let me (Score:4, Informative)
If you're interested in updating, take a look at modern split systems. The exterior unity comes in a variety of sizes, and the interior unit is attached to an interior wall, so it is not as size constrained as your old system.
Re:I wish I could - the government does not let me (Score:4, Insightful)
Electric heat is 100% efficient. It turns 100% if the electric consumed into heat.
Electric heating is really only 10% efficient. You do convert 100% of the electricity to heat technically (as in the metal heats up that much) but the air only picks up about 10% of that and the heat transferred to the air is what counts. That's why your heating bill is so high if you use electric resistive heating in the winter. BTW, for comparison, burning natural gas is 97% efficient at producing hot air (only a politician makes more hot air). So if your grid has more than 30% natural gas (even if the other 70% was CO2 free), then electric heating actually makes more CO2 than just burning natural gas directly for heat. I think you are confusing heat pumps with electric resistive heating which are worlds apart.
Re:I wish I could - the government does not let me (Score:4, Informative)
ut the air only picks up about 10% of that and the heat transferred to the air is what counts.
Uh, there's heat energy still in the coil when it shuts off, but I can guarantee that the air, at least eventually, picks up nearly 100% of that heat.
Where the efficiency comes in when you look at things like natural gas is that while electricity is 100% - 100% of the electricity consumed by the heating element is converted to heat, there are lossy steps before that. Such as a state of the art natural gas plant might be 60% efficient, though 42% might be a better figure. [nas.edu] Then knock off another 10% or so for line transmission costs.
So, if you're putting a natural gas furnace that will be ~90% efficient up against straight resistive coil, unless you're using renewable power, burning the gas for heat is actually more efficient than heating with electricity. If you're heating your place with, for example, hydropower, then that's different.
Heat pumps can be more than 100% efficient, so that can flip the equation again. If you're getting 4 units of heat for every unit of electricity spent, that's more efficient that way.
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And where does the rest of the 90% go? It all has to get into the air eventually, be it inside your house or outside. Natural gas is not necessarily more efficient. It's just much cheaper, and can produce a heck of a lot more heat (faster) than other sources.
Been doing this for years (Score:4, Informative)
In our part of the world they're just called "reverse cycle" air conditioners. Had 4 of them running in my home for nearly 10 years and it's commonplace technology that certainly shouldn't be "news". I wouldn't count on it to get me through a winter that hits freezing or below but it's absolutely good enough for what we go through. Got one running in our main living space upstairs right now and it's doing a great job.
Re:Been doing this for years (Score:4, Insightful)
For what it's worth, I live in Canada and I've run on heat pump alone (no electric heating) down to 14 Fahrenheit quite comfortably. Heat pumps can run below freezing and would work fine in most parts of the US.
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I didn't know they still made air-conditioners that weren't reverse cycle any more.
This truly surprised me as well. I own a house in Australia and as a sweetener to keep our tenants a few years ago I offered to install AC. I bought literally the cheapest split system I could find anywhere and it was a reverse cycle unit. $500 MORE expensive? This thing cost less than $500USD all up.
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Makes me remember just how much America is under the thumb of self-serving corporate interests. If a company can save a bit of money by making a simpler product then they will; what the consumer actually needs isn't part of the conversation. Now if the consumers turn around and start buying the right product then there is motivation to sell it, maybe the competition heats up and then it's more available. But it all centres around the bottom line: profit. Raw capitalism is great for some things, terrible for
Depends on where you are (Score:4)
We're behind The EU in some ways, but if you look at things like home insulation, we're far ahead of the Japanese(on average). Thing is, remember, much of the USA is already on heat pumps, the house I'm in is actually on it's third heat pump system. The problem seen here is that air conditioning systems(IE cooling systems) are moving north, so you have people with established heating systems that you're trying to convince to spend the extra 20% or so to go with a heat pump over just an AC, when they have a perfectly serviceable heating system already.
In temperate regions they're common (Score:2)
If the day is too cold, you may need something extra to get to the right temperature if your house is not properly isolated.
Looked into this recently (Score:2)
I live in the SF Bay Area and need to replace my central AC units. Converting to a heat pump is a surprisingly small delta, about 20% IIRC. It's not surprising when you think about it: all it takes is adding some diverter valves and probably re-engineering the heat exchangers to work at both high and low pressure.
I'm still on the fence about it. In our area, we're on the edge of wanting to still have a gas furnace for back up use on very cold days. Not having to buy a furnace makes the numbers much more att
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Is it bad form to reply to my own post?
Turns out, you can also buy heat-pump based water heaters and clothes dryers. The dryer is really interesting: hot air only exists inside the unit so it doesn't need a vent and doesn't need to draw in outside air.
The impression I get is heat pumps are getting cheap enough and reliable enough that we can start thinking of them in all cases where we want heat. I wonder when I'm getting a heat pump oven or stove...
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Anyone telling you that you need a backup gas furnace in the SF bay area is lying to you. The higher end heat pumps have supplemental electric heating ("heat strips") built in, but even that is probably unnecessary for the weather you get. Supplemental gas heating is for places that routinely get temperatures below about 20F.
I'm also in CA and I have a heat pump. It has no problem with the winters here.
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That wasn't the main concern for me. It was something I could do to lower my carbon footprint. Maybe it will pay for itself and maybe it won't. Even if it doesn't, it will come close enough that the lifetime cost will be pretty minimal. I'll gladly pay that cost to do my part to fight climate change.
For me, it was measured in thousands of dollars per year, but that's what happens when your per kWh price is something like 38 cents....
New Tech - From Tesla? (Score:2)
There is a great video on how heat pumps work (Score:2)
The Technology Connections YouTube channel has a great video explaining just what heat pumps (or as we call them in Australia, reverse cycle air conditioners) are, how they work and why they are such a good idea.
There is another video explaining ground source (aka geothermal) heat pumps and why they are such a good idea.
Not all coal fired electrical generation in the NW (Score:3)
The point is that too many people think that using electric devices means it is just hiding the use of coal and other fossil fuels for generating electric power. In too many places that is true. But in many places it simply isn't. The population may be less than California's, but Canada has virtually no coal powered electric generation, except maybe for Alberta. And Canada sells (actually we get ripped off because the politicians here basically give it away for free or even subsidize it) electricity from hydro generation to America. New York state and much of the north east gets much of their power from Ontario, Quebec, and even Newfoundland.
Radiators (Score:3)
In the UK is rare for houses to have forced air heating. There were a few built this way in the 1960s, and I nearly bought one, but what put me off was the forced air heating which would have been expensive to run and which I would have wanted replaced by radiators or other more traditional methods. You can team radiators up with heat pumps (ground or air source) rather than using natural gas for heating.
But I wonder if it's possible to run radiators cold in summer? E.g. have something chilling the water and whether that would help cool rooms. Convection would not be in your favour (*). Underfloor would be more effective both for heating and cooling I would expect, but would also need a lot of retrofitting, doesn't necessarily work with floor coverings as well (I have pets and no carpets but that's not common). Cooling of this sort, if effective, might work well with heat pumps. I would seriously have my doubts that the typical size of radiators in the UK would be effective, even with cool or cold water being continuously pumped through, though, but the advantage would be not having to retrofit every room when the need for air con in the average UK home is relatively infrequent.
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Pretty much this. An important factor to consider is that the compressor runs in both cooling and heating modes, unlike a traditional cooling only air conditioner, so those additional months of service each year shorten its lifespan.
Another important distinction to make, and TFS touches on this, is that the heat pump only works well down to about 30 degrees F (-1C), and when it cannot keep up with demand, expensive electric heat strips come on inside to compensate. A four to five ton central air conditioner
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You can use traditional natural gas heat when it's too cold to be efficient with a great pump. If these homes already have that, they don't need to get rid of it.
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Heat pumps can use other secondary heat sources, like gas, not just electric. In those setups, electric strip heat can often be set as a third / emergency source. (The electronic thermostat for my heat pump has settings for all that -- secondary source type and optional third source.)
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That's a really good setup, the dual fuel system... the caveat is that the equipment cost alone is twice as much as a conventional heat pump or gas heat A/C system.
Typically, folks with access to municipal natural gas systems have gas heat, and folks outside the delivery system heat with electricity, propane, wood, or heating oil. At present, these are all inferior substitutes.
Heat pumps are incredibly more efficient than warming up the house with heat strips (think toaster coils in your air handler), but
HVAC techs will confirm (Score:2)
If government shall mandate them reliability standards must improve considerably! They can of course as the additional parts can easily be made more robust.
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Why does the fraking Government have to do Everything?
So you agree that we should stop the environmental subsidies and tax all pollution the amount of money it costs to clean up? You think we should cut all subsidies to farms and cattle ranchers? Should we even limit the amount of federal funding a state can receive to amount they put into the federal government?
Which subsidies did you want to end first?
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Way to put words in someone else's mouth. He didn't say anything about taxing anything. Good grief!
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That's a pretty extreme leap of logic. I75BJC only suggested that people should buy there own air conditioning units and/or heatpumps.
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So you agree that we should stop the environmental subsidies and tax all pollution the amount of money it costs to clean up?
Sure. Sounds good.
You think we should cut all subsidies to farms and cattle ranchers?
Absolutely.
Should we even limit the amount of federal funding a state can receive to amount they put into the federal government?
Fine with me.
Which subsidies did you want to end first?
We should end them all simultaneously.
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Why does the fraking Government have to do Everything?
Have you not watched how the public reacted during a pandemic?
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The tide-pod challenge was around long before the pandemic. We didn't get any worse during the pandemic - a bunch of us just assumed people could pull their heads out of their asses for a minute and take care of serious business, but that turned out to be a bad assumption.
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The tide-pod challenge was around long before the pandemic. We didn't get any worse during the pandemic
Heh. If you're going strictly by memes, maybe. To get a Tide Pod death count as high as 15 you haveta include non-Tide-branded detergents. Oh and the government did not intervene with Tide Pods. I don't get how the situations with anti-maskers, anti-vaxxers, COVID parties, etc didn't end in 'worse than Tide Pods' with you.
Re:Another Government Boondoggle in the Making (Score:5, Interesting)
They don't, but individuals can't do everything themselves either. This story by Scott Alexander explains the basic problem: [slatestarcodex.com]
The problem being described here has a technical term, "negative externalities". As far anyone can tell, individuals working independently cannot entirely prevent negative externalities. That's where democratic governments come in. Coincidentally, the problem in this lake is the same sort of problem as global warming; some CO2 is normal an necessary, but too much makes the planet warmer. Asking people to individually stop using fossil fuels is absurd and unnecessary, but with a carbon tax here and a temporary subsidy there, we can all switch to clean energy with no significant reduction to our quality of life.
My favorit
Re: Another Government Boondoggle in the Making (Score:5, Insightful)
That's not a flaw, that's the natural and very much undesirable end point of the thought experiment. There is a boundary condition: people still have a desire to have eat fish.
As a result fisheries that adapted first by putting in voluntary quotas and perform ecologically sound fishing practices and commercially promoting their products as being either farmed or dolphin-safe etc are the ones that survive while the trawlers from the 90s are doing poorly.
And if you look a bit closer you'll see the "voluntary quotas" have followed the thought experiment perfectly. The world is being massively overfished everywhere and even with voluntary quotas the fishing industry continues to do massive ecological damage. Enter governments.... unfortunately they are imperfect as they fall heavily for lobby power of the very greedy fishers being described in the thought experiment.
If you think any of the fishing we're doing right now is environmentally sound then you're really not paying attention.
Re:Another Government Boondoggle in the Making (Score:5, Insightful)
People, learn to take care of your own selves!
People do take care of themselves. Only themselves. Not others. Not the environment. No thoughts on the consequences beyond themselves. This is fundamentally why governments have to exist in a functioning society.
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There are about three different reasons for why the government is FAR better at many things than other options. Also, the government does not do everything, you should try living in China to see what a real government that interferes in your life does.
1) Government spreads costs out over everyone, rather than over a smaller group. This is the same concept behind Insurance - 20 people afraid of fire buy insurance, but only one has a fire and is paid off. But optional insurance means both that some will
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Basically, the smaller the government, the smaller the minds, and you get horrible bureaucracy.
If you believe that higher levels of government have bigger minds, I've got a bridge to sell you. The amount of bureaucracy increases an order of magnitude with each level. I had plenty of opportunity to witness some of it up close in my ~37 years around the beltway. There's extremely little that's efficient in the federal government.
And, I'll grant you that HOAs can be a shitstorm, but they're not all.
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As long as you don't mind forced air heating, it only costs a tiny bit more to make a reversible heat pump instead of an air conditioner. So if government would step in it wouldn't be to force installing heat pumps, but to make sure every airconditioner is designed as a reversible heat pump.
Don't all airconditioners have reverse cycle? (Score:2)
It would be difficult to buy one without it in Australia.
The limitation of reverse cycle is that it must not get too cold outside, about 5C is the lower limit or they lose efficiency and ice up.
Which works well in Australian cities that rarely get below that. Maybe not so well for Canada.
When it is hot, the sun is usually shining, so plenty of solar for air conditioning.
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Maybe not so well for Canada.
Even in Canada, ground-source heat pumps [wikipedia.org] can work.
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De-icing cycles don't consume that much power and with a buffer tank it has no impact on comfort either.
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Yeah, heat pump costs more to operate than a natural gas heater.
If someone is building a new house, then a heat pump may be a cheaper option than the install costs of natural gas pipe and the heater. However, if someone already has a natural gas heater, then it makes more sense to just continue using it, even if the AC has a heating function.
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Maybe because most people don't have 30 grand sitting around to retrofit a heat pump? I've long been a fan of heat pumps but am under no illusions as to the up front installation costs. And that is the deal breaker for most.
I've had a top end heat pump installed with existing central air ducts for less than 30, there's no way the mini-split retrofit systems I've seen popping up all over the northeast cost 30k?
But even 10k in rural Maine is still a hell of a lot of money when your thirty something year old oil furnace still works. I think there already are incentives to upgrade to heat pump water heaters and home heating too, and it does make a lot of sense to me to keep helping people offset install costs to get into a system
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Maybe because most people don't have 30 grand sitting around to retrofit a heat pump?
Re-read TFS, no one is talking about asking people to retrofit anything. Also $30k, are you mad? Or do you very much live the American stereotype that you all own massively oversized inefficient McMansions that use an exorbitant amount of energy just to maintain a semblance of comfort?
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30 grand!!! Holy crap, I got a ducted heatpump installed for 3 bedrooms for NZ$7k, which is around US$5k. Costs around NZ$2k for another one for living room area because I want them separate.
Awesome for winter and summer!
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Not all air-conditioners are the same, efficiency wildly varies. What you need to do is rather than look at the KW power used to make the system work, you look at the actually cooling and heating it can produce at what temperatures. People get caught out bad with very inefficient systems, inefficient motors, cheap compressor, small evaporator and condenser coils (low heat transfer more pumping required). At one stage Daiken and Mitsubishi Electric were the top, not sure now, the rest were really inefficient
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My heat pump was only $3,000 installed, and it heats/cools an entire floor of my home. I'd need a second to cool the entire house, but that's still nowhere near $30,000.
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Pay the bank interest to get an education. Pay the bank interest to own a car. Pay the bank interest to buy the house. Pay the bank more interest because your down payment wasn't large enough. Now pay the bank interest to make a miniscule dent on climate change.
Maybe we should just bring back indentured servitude while we're at at.
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"Maybe we should just bring back indentured servitude while we're at at."
Bring back? What ever makes you think it went away?
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Agreed that subsidies shouldn't be necessary for widespread adoption. A friend in Dallas replaced his resistance heating with a heatpump and enjoyed a payback period of ~3yrs. You don't need to incentivize a 33% ROI.
The problem is that in the Pacific Northwest, resistance heating is already rare. The cost of electricity is too high. Everybody uses natural gas for heat. And that's actually a big problem for any hope of getting people off of natural gas, because natural gas is cheap.
My air conditioner is on its last leg, and I'm about to have to replace it in the Bay Area (PG&E territory). I did some quick math and figured out that a heat pump would cost me about four times as much as natural gas. The only way t
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Take a shot, give a shot...
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So you are claiming a heat pump won't cool under some situations when an A/C system will? Why is that? Not sure why you are making this claim since an A/C unit is a heat pump; it's just a one-way heat pump though. We use heat pumps in our bee incubation building. They work just fine to cool at any temperature normal A/C would work.
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I don't see "not an air conditioner" anywhere in the summary. what you are referring to? Can you point me at information that describes why the heat pumps (such as mini splits) cannot work at hot temperatures to cool, when A/C units will?
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If Americans are going to buy air-conditioners anyway, either for the first time or to replace older units, why not convince them to buy electric heat pumps instead?
I read "instead of an AC" as "not an AC".
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Ahh yes. That's just people drawing a distinction between one-way heat pumps (an air conditioner) and two-way heat pumps. However the distinction is only minor. A heat pump *is* an air conditioner. Uses the same refrigerant cycle. These folk want to incentivize buying the two-way heat pumps vs the one-way. In many countries they simply don't offer the one-way heat pumps that we're used to in north america. Someone mentioned you can't buy an air conditioner in Australia without the reversing valve.
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This is very interesting. We've had weather above 90F for several weeks now and our mini-split heat pump units are cooling just fine, easily holding the shop to 70. What causes the heat pumps to not cool when it gets hotter, other than the fact that most central A/C pumps cold air throughout the house whereas mini split heat pumps just cool from one spot on a wall? Are you saying the mini split won't generate cold air when it's really hot out, or just that a central air system that blows air through the
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Your window AC works by “air heat exchange” as well. All ACs are “heat pumps”. They collect heat from inside using a refrigerant and reject it outside. It’s just that if it’s one way we tend to call it an air conditioner and if it is reversible we call it a heat pump.
If you are only getting 4C of cooling maybe what you have is a swamp cooler. That is about in the ballpark for what they are capable of.
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An air conditioner is a heat pump, a reversible heat pump can be an air conditioner and a heater.
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A heat pump has no compressor like an AC.
Uh, what exactly do you think a heat pump is?
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I suspect that for a given subset of Americans which some people here are part of, swamp coolers and heat pumps are synonymous for some unfathomable reason.
This is not the common sense or the common technical definition of the word. Generally heat pumps do have compressors.
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Homes in the PNW already have furnaces. The most common way to add A/C to an existing home is to buy a mini-split heat pump which are not expensive and don't replace the furnace, although you can heat with them down to about -20C, and from a pure energy pov they are several times more efficient at heating than gas, although not cheaper.
I've seen that claim in other posts. Why wouldn't they work for cooling anywhere an A/C unit will? An A/C unit is a heat pump, just not reversible.
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Heat pumps only work well And a narrow optimum range of temperature. You still need an air conditioner and a proper furnace For any kind of extremes.
Air conditioner IS A HEAT PUMP, you dummy.
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You DO know that a heat pump is an A/C unit at it's heart, yes? The difference is that it has a reverse valve to allow the refrigerant to be condensed inside and evaporated outside in the winter.
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Your understanding is incorrect. It's the same refrigerant used in any A/C unit.
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That's incorrect. A heat pump uses conventional refrigerant. Which is a gas. When you install them, the main evaporator comes holding a vacuum. After you connect the coolant lines you crack the valve and the vacuum pulls the coolant from the one unit through into the other unit. Except fort he complication of the reversing valve and the electronics that go with it all, they are identical to air conditioners.
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Heat pumps only work well And a narrow optimum range of temperature. You still need an air conditioner and a proper furnace For any kind of extremes. And now you have more complication, resultimg in more points of potential failure. So its gpimg to be more expensive for maintence troubleshooting and more often.
OK this is the second person in the comments to say something like this. I think you and fluffernutter need to go google "how do heat pumps work" before commenting any more.
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Then what is that compressor attached to my heat pump? And why do I need to have the refrigerant level checked occasionally?
What you're saying is false. A heat pump is an air conditioner. It works in exactly the same way any other air conditioner does. The only difference is that it can transfer energy in either direction, while a conventional AC can only go in one direction.
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I think there are a lot of people confused about what a heat pump is. All a heat pump does is transfer heat from one side to the other. An air conditioner compresses refrigerant. It's the compressor that takes all the power. A heat pump has pumps but not a compressor.
I think only a few people including yourself are confused about how they work. A heat pump most certainly does have a compressor and uses refrigerant. They work the same as every other residential AC. The big difference is that the ones talked about in the article can also work in reverse, so pulling heat from the outside air and moving it inside in the winter. Watch this video, the first one is the most common type of heatpump in US homes: https://www.youtube.com/watch?... [youtube.com]
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We have a heat pump with gas as the backup heating. No heat strips.
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They absolutely suck in cold climates
We have relatives in New Hampshire who heat and cool their large house with a geothermal heat pump system. It works really well, even when it was -20 one time when we visited. https://www.energy.gov/energys... [energy.gov]
relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.
Though I suspect they're more expensive to install.
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Re: I use a heat pump for my pool (Score:5, Informative)
Re: I use a heat pump for my pool (Score:2)
Heat pump = runs backwards, in the US. Smart (Score:4, Informative)
In US usage, a heat pump is an air conditioner that can "run backwards" to work as a heater.
Specifically, a heat pump has a valve on the o/b thermostat wire which reverses the flow of refrigerant.
Heat pumps are a smart idea in places that you use the AC a lot more than the use the heater, such as Texas. Even if you didn't care about the environment, it's better for your wallet - especially compared to direct electric heating. (Direct meaning the kind where the first time you turn it on in the winter you can smell the dust burning off).
That's all there is for heat pumps. Now for a different topic, inverters. Inverter or not is an orthogonal thing. An inverter AC can be a heat pump, or not be. An inverter style had the ability to run the unit faster or slower to provide the needed amount of cooling. This is more efficient than cycling it on and off, as non-inverter systems do. It's a good idea to look at pricing differences for inverter systems. If it's a couple hundred bucks on a $3,600 install, the inverter option is worth it. It'll lay for itself in lower electric bills, eventually.
Yet another topic is the mini splits mentioned. Mini splits are normally inverter based, but you can have an inverter that's not a mini-split. The distinguishing feature of mini-splits is that you don't have one indoor unit attached to ducts that run through the house. Rather, you put the indoor unit directly into the room you want to cool. Either wall-mounted or in the ceiling. If you want to cool a 2,000 sq foot house with a mini-split, you might have two or three indoor units.
The advantage of a mini split is that you can save energy / money by setting the temperature differently in different rooms. You can cool your bedroom without paying to cool your storage room at the same temperature. You can even mount a unit in the garage and use it only a few days per year when you have to be out there in the hot summer. You aren't paying to cool a particular room except for when you want to cool that room.
Mini-splits should be considered when you're adding air conditioning to a home that doesn't have it. They are particularly suited to existing homes that don't have ducts for central heat and air. They may be a good choice for some homes that have ducts.
A less-common option that can make sense in large homes is to connect mini-splits to the existing duct work. If you're like me and you have 3,500 sq feet but spend 90% of your time in one 400 sq. ft room, why pay to cool eight times as much space as what you're actually using that evening?
Clarification on ducted mini splits (Score:3)
To clarify the last option, you'd divide the existing whole-house duct system into zones. In that way you convert a central AC into a mini-split system, without having to hang the indoor units on your walls.
Also btw on what the term "mini-split" as all about.
Split means there are separate indoor and outdoor units, it's not a self-contained window unit or motel-style unit that sits in the wall.
Mini refers to the fact that rather than one big indoor unit for the whole house, there are potentially several smal
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Re: Heat pump = runs backwards, in the US. Smart (Score:5, Informative)
There are two ground options and they are largely understood: vertical and horizontal.
"Vertical" means drilling holes of ~3 inchea diameter about 100 yards deep. Barring any volcanic activity you'll almost universally find about 17 ÂC there, which is the perfect compromise between cooling and heating. If you reach 20 ÂC or more (e.g. on "hot" tectonic ground) cooling efficiency goes out the window, but heating works better. You need one such hole for every ~120 m (that's roughly 1000 sqft or so). Should cost about $2-4k per hole plus $5k offset for first setup. So it's affordable.
Problems are: stony soil, and/or ground water restrictions. Also retrofitting might be difficult as the drilling rig needs space to enter your property, mount, and work (if you have that, it's nit a big problem).
"Horizontal" means digging up your garden for about the same surface as the surface you want to heat/cool within your house (1-2000 sqft?) and laying a ground of tubes 1-2 feet apart. Cover everything up and there you go. At 2 feet you essentially never have freezing temperature, so it's still a good deal.
Problems: you cannot plant trees or strongly-rooted plans or they might destroy your tubes. And you're "stealing" away some energy from the soil, meaning plants, lawn, bushes etc. might be slightly more effected - nothing to worry about unless you absolutely need all the growing capacity of your soil for growing food to sustain your living. But all in all it's a perfect retrofitting option.
Beware of from the reservoir site (garden, holes, ...) to your heat pump i.e. house walls. That you can mitigate through better insulation of the pipes. But the absolutely best option is to drill/dig first, before you even lay your foundation. Then build on top of that - then you (a) have direct access to the pipes from your basement, and (b) you use only property surface which is going to be lost anyway for other purposes after your house is finished.
But all in all: unless you absolutely don't have the space or the soil to drill *or* to dig horizontally, retrofitting is absolutely possible and $10-20k ballpark will get you there.
Source: I've drilled 4x 100 m holes after the foundation was laid, but before the house was finished :-) That was 10 years ago and cost $10k. This winter we're going to install the heat pump, so I don't have any 1st hand numbers yet, only estimates...
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I came here to say the same thing. I think (pretty much) all Aussie aircon's have been reverse cycle for closer to 30 years. I grew up in Tassie. Something like 35 years ago heat pumps were all the rage (and Tassie is hardly known for being the most advanced in the word), So that this is an discussion point really is a WTF moment. (The heat pumps 35 years ago really were that - they did not have a cooling option. These days it is all reverse cycle obviously).
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You still "win" more than those people using a baseboard heater as a massive resistor to heat their place. Especially if you're both using the same dirty electricity because the heat pump will use a lot less of it to heat the same amount.
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