Europe is overheating. This climate-friendly AC could help.

[mahatmakanejeeves]

INNOVATIONS

Europe is overheating. This climate-friendly AC could help.

Heat pumps are efficient and eco-friendly. So why are they so rarely used?

By Pranshu Verma
Updated July 21, 2022 at 10:56 a.m. EDT|Published July 21, 2022 at 7:00 a.m. EDT



A row of terraced houses in Guilford, England, taken with a heat-sensing camera in December. Brighter areas show where higher amounts of heat are emitted. (Jason Alden/Bloomberg News)

The United Kingdom declared a national emergency this week during a historic heat wave that’s melted runways, snarled train travel and shattered temperature records. The devastation has been particularly acute in a country like England, where 95 percent of the population lacks air conditioning. ... Amid that, the British government has provided grant money to a little-known solution: heat pumps.

Bearing a misleading name, heat pumps are two-way air conditioners that move warm air from inside a home to the outside, keeping dwellings cool in hot months. In winter months, they do the reverse, taking heat energy from outside and pushing warm air in.

Energy officials, lawmakers and scientists tout the devices as inexpensive, energy-efficient systems that significantly reduce greenhouse gas emissions over traditional heating and cooling devices.

Estimates show that 90 percent of Japanese households use heat pumps to heat and cool homes, contributing to a 40 percent drop in the country’s electricity consumption over the past decade. In Italy, the government effectively pays citizens to use the technology; homeowners can get 110 percent of their heat pump cost reimbursed.

{snip}

By Pranshu Verma
Pranshu Verma is a reporter on The Washington Post's technology team. Before joining The Post in 2022, he covered technology at the Boston Globe. Before that, he was a reporting fellow at the New York Times and the Philadelphia Inquirer. Twitter https://twitter.com/pranshuverma_

[Irish_Dem]

1. I have a heat pump but was told never to use since it is outrageously expensive.

I have never used it so I don't know if that is true or not.

[SheltieLover]

2. I have a ductless inverter system (variable speed)

Elect was $70 last month, including the 40% rate increase!

If you pm me make & model I can have my resident exprrt guestimate cost to run for you.

Heat pumps are usually much less expensive to run, generally.

[Irish_Dem]

5. Thanks Sheltie!

This is all I could find on the unit. It was put in by the builder before I moved in.

Goodman Manufacturing Co.
P/N: IOG-4002B January 2018

On my thermostat the heat pump is called "emergency heat."
And I was told to use it only when temps are extremely cold.

[SheltieLover]

11. Yw!

What type of climate are you in?

Grrrrr goodman. Guessing you are in south?

Emergency heat costs sever times more to run because it turns the heat into electric heat.

Does it have normal heat mode?
I'll have him check when he gets back & let you know.

[Irish_Dem]

14. Answers:

I live in Ohio. So hot in the summer, cold in the winter.
But not many days of a deep freeze.

Yes I have three settings: Heat, Cold, Emergency Heat.

It is all electric.

Many thanks Sheltie!

[Salviati]

3. You should make that judgement for yourself.

and based on how new it is, and what you're using it for.

Using it as AC, it will be more or less equally as efficient as any other AC of it's age. Using it to heat, it's operating costs will always be more cost effective than direct electric heating under any circumstances, and whether it's more cost effective than other forms of heating will depend on it's performance, the costs of electricity vs. other forms of heating, and the temperature differential you're creating.

A blanket statement that they're outrageously expensive may be very out of date. Newer models are often cost effective in places where they would not have been a decade or two ago, e.g. even in all but the absolute coldest times of the coldest days of Chicago winters.

[Irish_Dem]

7. Very interesting, thank you.

On my thermostat is is called "emergency heat."

The builder who installed said it is only to be used when it is very cold outside.

[Salviati]

8. Something seems a bit strange...

A heat pump is going to work very well when it's not very cold outside. The smaller the heat differential between inside and outside, the better the performance will be. But when it's extremely cold outside, the heat pump may not be able to deliver as much heat as needed in order to keep your home warm, so there's often an option to have direct electric heating, which I suspect is the "emergency heating"

From your understanding, what is the source of the heat when it is not on "emergency heat"?

Otherwise, I suspect that you got some bad instructions, because I don't think there's any circumstances where using a heat pump like that would make sense for heating.

[Irish_Dem]

13. Thanks for giving me this information.

Last edited Fri Jul 22, 2022, 06:30 PM - Edit history (1)

My neighbors got the same information, we all moved in about two years ago.
New condos.

I have electric heat and AC. What is direct electric heating?

I have an installation handout on the heat pump and is says it is a "Condensing unit/heat pump."

I have three settings on my thermostat. Heat, Cold, Emergency Heat.

The builder said to use the emergency heat setting during a cold snap as using the regular heat would "freeze up and ruin the motor."

So now I don't know what the deal is. The neighbors were told the same thing, we have discussed it. (Because the neighbors were saying don't use the emergency heating. It will cost a fortune.)

So maybe the builder got it wrong. Or the neighbors did.

[Salviati]

17. Yeah, it sounds like you got bad instructions, mainly about what is happening, not what you're doing

Electric heat will transform electrical energy directly into heat, this generally has an "efficiency" of 100% because all of the electrical energy you use, gets transformed into heat. It's not really ideal though because electrical energy is a more sort of "refined" form of energy, in that you can use it to do a lot of things, and depending on where you're getting it from, there might be a bunch of fossil fuels burned to generate it.

E.g. if your electric power comes from natural gas fired plants, they might get a typical efficiency of about 40%, so forty percent of the energy in the natural gas is turned into electric energy, and then transmitted to your house, where it is converted to heat. A natural gas furnace, on the other hand, takes the natural gas into your home, and burns it to directly produce the heat. Modern furnaces can capture somewhere about 95% of the heat in your home.

Electric heat is way simpler, and there are other issues with running a system of natural gas pipelines all over, but clearly on a "how much of the original energy winds up causing your home to be warmer" criteria, the gas furnace is better.

Heat pumps, on the other hand use electric power, not to generate heat energy, but rather to pump heat energy from outside your home to the inside of your home. Heat naturally wants to flow from higher temperatures to colder temperatures, but if you're willing to pay for it (by adding more energy) you can "pump" it from cold to hot. (Like water wants to flow from high elevations to low elevations, but you can make it go the other way with a water pump.)

The fantastic thing is that with 1 unit of electric energy, you can usually move way more than 1 unit of heat energy. With relatively new models made in the last few years, if it's not too cold out, you can often get up to 5 units of heat to warm your home for every 1 unit of electric energy. That's like having an (impossible) electric heater that operated at 500% efficiency. And even as long as the performance is about 2.5, which is very reasonable for modern heat pumps, it's even more efficient to use a gas powered electric plant to create electricity and using that to run a heat pump than just burning the gas directly for the heat.

So I suspect, under normal conditions your heating is provided by the heat pump. When it gets really cold, it may just not be able to produce the volume of heat required to maintain a reasonable temperature, then the emergency heat would allow you to turn on direct electric heating (which would be much more expensive than you'd be used to, to output the same amount of heat it would likely use 4-5 times as much electricity...)

So long story short, it sounds like you should continue using your heating like you have been, but what's actually happening is likely the reverse of what you've been led to believe. The normal operation is using the heat pump, where the electric energy is being used to pump heat to the indoors from the outdoors, while the emergency heating is there for conditions where it's too cold for the heat pump to do its job effectively, and turns electric energy directly into heat.

[Irish_Dem]

21. Thank you for the explanation.

Ok that makes sense. So the builder was confused or the residents were.

So I have a heat pump but direct electric heat when it is too cold for the heat pump.
I have never hit the emergency heat button but now will feel better doing so.

The heat pump works really well, condo is cool in the summer, warm and cozy in the winter.
I don't have high electricity bills either.

Thanks again! Appreciate it, I learned a lot.

[SheltieLover]

12. So far no rating with AHRI

American heating & refrig inst. 3rd party that verifies efficiency ratings.

Not surprising for goodman.
(Shitbag company to the nth degree!)

He is researching.

General rule of thumb: use heat pump unless it breaks, then use emerg heat if you need it.

Bbs.

[Irish_Dem]

15. Interesting

I am not surprised it is not top of the line.

It is a nice, new condo, but the builder liked to cut corners whenever possible.

I will say it does a good job, condos are well insulated and I am cozy in the winter and cool in the summer. I cannot complain. In fact now when I visit a friend or relative in a house during the winter, they feels so drafty compared to my condo which feels so snug and cosy in comparison.

Luckily we have not had a serious cold deep freeze in the winter, so have not had to switch to the emergency heat. One of my neighbors said if you turn on the emergency heat, even for a short period of time, it can cost $1000 easy in addition to the regular heat bill. Don't know if that is true or not.

Thank you so much Sheltie for the information!

[SheltieLover]

16. Your condo sounds great!

FYI, Daiken bought Goodman in 2012.

https://www.daikin.com/press/2022/20220311

If you ever replace it, go with Mitsubishi or Trane. Both last forever & offer super energy efficient models.

The rddnecks in TN just love Goodman.

Me, not so much. Bought an older home a few yrs ago with a Goodman gas furnace. It was such a piece of unsafe garbage.

Had no safety features at all & when the lovely lady who sold me the house decided to physically crush the inside of the chimney pipe just before we closed, it was literally shooting flames 3-4' out the front when it would start up. No flame roll-out protection, among other things.

Replaced it with a ductless mini split & loooove it! Lots of heat & cool is lost through ducts, esp if you ive somewhere like this where tradesmen are mostly to lazy & stupid to seal ducts. I could tell you horror stories, but I'll spare you.

A great you tube channel to learn about hvac is gray furnace man, just in case you ever need service.

Enjoy!!!

[Irish_Dem]

19. Good advice.

Yes I would go with a Trane or Mitsubishi.

The builder's headquarters is in Kentucky so makes sense that he went with Goodman.

My God, the owner who sold you her house, crushed the chimney pipe before you closed. Good God. What a mess. At least you were able to replace it with a much better model.

I have no idea how a ductless mini split works. I will have to look it up.
Thank you for the you tube reference, and the advice!

[SheltieLover]

20. Figures... 🙄

It's an inverter unit, meaning it runs constantly. Start up is when the most wear on the system & power consumption occurs.

Keep in mind, a system generally is either optimized for cooling or heating. I chose cooling because this climate is like living in "hell." Hot & humid, not to mention I'm heat intoletant.

Sizing the unit correctly is very important because if it's too small, it will struggle & if oversized, it will not dehumidify.

So, while it sounds inefficient to have the unit running 24/7, my power bill has dropped from near $300/ mo to $70-80/mo.

Not running the cooling (or heat) through ducts in a hot or cold attic or crawl space is incredibly efficient. Especially considering the horrid state of the duct work. Incredible!

Feel free to pm if you have questions. Always happy to help.

[Irish_Dem]

22. Thanks Sheltie

Yes I agree, your system sounds great, always running, efficient, no ducts.

I let you know what happens if I ever have to hit my emergency heat button during the winter!

[SheltieLover]

23. Yw!

Okay! Good luck with it.

[sl8]

18. I believe you're talking about a "resistive heat" mode.

If you look uo the thermostat/control unit that you have, I'd bet that your "Emergency Heat" setting switches on a resistive electric heater. Normally, you wouldn't want to use it because it uses much more electricity than when operating in the "heat pump" mode.

[Irish_Dem]

24. I looked at all the manuals.

No info on what exactly the "emergency heat" is. Figures they don't tell you anything!

I have a heat pump for regular heat and some kind person here on DU told me I probably have direct electric heat for emergencies. This must be the same thing as the resistive electric heater. Yes it is said to be expensive and to be used only when it is so cold the heat pump might freeze.

[NNadir]

4. Pretty much every air conditioner on the planet, excepting swamp coolers...

...is already a heat pump.

The same is true for refrigerators and freezers.

[Salviati]

6. True, but not all of them are designed to work both ways.

[NNadir]

9. True, but the OP suggests it in the context of of dealing with extreme heat.

I note that most of the world's electricity, delusional fantasies aside, still depends on the combustion of dangerous fossil fuels, the dangerous wastes of which are dumped into the planetary atmosphere, driving climate change.

Refrigerants, notably the HFCs that replaced CFCs are also potent climate change drivers.

It might be better to address the root issue, climate change, than to propose slightly modified bandaids.

[HelpImSurrounded]

10. Every air conditioner is a heat pump but...

Heat pumps work in the winter by "cooling the outside". The function of a heat pump is to draw heat from one side and push it to another.

This is fine in summer and in mild climates. However, as temps go below freezing heat pumps do not do as well and the electricity to run them gets expensive.

In contrast, a gas furnace is far cheaper for heating a home.

In severe cold, most heat pumps rely on "emergency heat" mode which is just an electric heater inside the air exchanger. In any scenario, electric heat gets expensive.

The only way to make it work economically for individuals is to tie it to individual wind/solar installs which may or may not be sufficient during the coldest periods.

[NickB79]

25. I installed a Carrier duct-tied heat pump to replace my 20 yr old A/C unit several years ago

I also replaced the furnace, since we're in the country on propane, and here in Minnesota we need either a gas furnace or a wood stove to survive at -25F (I also have a wood stove, so I have all my bases covered).

The unit, coupled with the smart thermostat, works efficiently for cooling even on the 90-95F days we've had this week, and for heating down to approximately 20F in March-May and Sept-Nov. I can enter the cost I pay of propane per gallon, and the cost of electricity per kWh, and the system decides when to use either one. Our electrical provider also provided a significant rebate and installed a dedicated box for the heat pump to give us off-peak pricing as an incentive to get more homes to switch over.

We've been saving hundreds in heating and cooling each year since we installed it compared to our old system (I keep a pretty close eye on how many cords of firewood and gallons of propane we use each year).

The downside is that, even with incentives, the upfront costs are easily thousands more than a basic A/C unit. It takes time for the savings to pay for themselves, and that's not what a lot of people like to hear. But, since we plan on living in our house for another 40 years, we've been taking the long view on most things related to home ownership.