Maybe you get that kind of efficiency with a heat pump in Texas, but here in cold-ass Pennsylvania and chilly, dreary damp England I really doubt it.

You don't see heat pumps around here much, there was a era maybe like 30 years ago when they were all the rage then when people found out they just don't work after a certain temp, they fell out of favor.

quote:

Originally posted by BBMW:
As far as heat pumps not being usable in cold climates, I think this is out of date information. I hear that they're being used in Canada, if that tells you anything about their applicability in cold climates.

The old story is that they needed resistance heating backup for when it became too cold to actually get the heat pump to work. However technology has progressed, and air sourced heat pumps can work to much lower outside temperatures.

https://www.nrel.gov/news/feat...-us-mass-market.html

You might want to read the entire article you posted and then read PASig’s link.

The heat pumps of 30 years ago are not today's heat pumps.


My heat pumps (three) are from 2004, 2006, and 2013. They all pale in efficiency to the newer models. My wife and I will likely swap out our old ones. As, like you mentioned, the older ones don't work as well at 30f and lower. The newer models do.

Here is a couple excellent break down videos.

quote:

Originally posted by PASig:
Maybe you get that kind of efficiency with a heat pump in Texas, but here in cold-ass Pennsylvania and chilly, dreary damp England I really doubt it.

You don't see heat pumps around here much, there was a era maybe like 30 years ago when they were all the rage then when people found out they just don't work after a certain temp, they fell out of favor.

Look at “Coefficient of Performance” tables for modern air-source heat pumps.

With air temperature of -20 C (-4 F) and output temperature of 45 C (113 F), the COP is still around 2 (twice as much heat moved as energy consumed).

Like I said, there are climates where they aren’t ideal, but they work well in a MUCH wider climate range than they used to.

If you’re in Wyoming or North Dakota, probably not a good choice, but England doesn’t get THAT cold. From 2015 to 2021 there was only one month where the temp went below 0 C (32 F), and even then it was only -0.4 C (31 F). https://www.statista.com/stati...perature-in-england/

At 0 C (32 F) air temp, a modern air source heat pump can put out 65 C (150 F) with a COP around 2 or 45 C (113 F) with a COP around 3.

I’m not saying heat pumps should be legally mandated, but modern ones work perfectly fine in a climate like England’s.

NYC already passed the same for new construction and gut remodels, no more gas or fuel oil. Out sweet Govnor want the entire state to follow in the next, I believe it's, 7 years. I'll be gone in 2 and they can do what they want.

Current generation heat pumps work well down to about 40 degrees F. Temperatures that stay below that regularly you’d better have dual heat. My system switches to gas at 40 degrees F.

And another thing the environmentalists don’t mention is noise pollution. The colder it gets, the more a heat pump cycles in and out of defrost mode. Ever been in a subdivision that has only heat pumps? The noise pollution is terrible when temps are low. Couple that with 10kw heat strips running regularly due to the colder temps and the heat pump not being able to maintain the indoor temperature and many more defrost mode cycles/day (heat strips also run during defrost mode) and you’ve got ridiculous electric bills.

quote:

Originally posted by maladat:

Heat pumps are not ideal in all climates, but there's a factor you're missing from an efficiency standpoint.


A heat pump works differently. It doesn't turn its energy input into heat. It uses its energy input to move heat from one place to another. A high efficiency heat pump can put 4-5 times as much heat into a house as it uses electricity.

A high efficiency electric heat pump using power from a 50% efficiency gas powerplant can heat a house with 200% or more of the energy in the gas that was burned in the powerplant.

I didn't realize HP's work at 500% efficiency now, I thought they were around 300% and only then at moderate temps, less as it gets colder. At 500% that changes things.
I heat my home with a heat pump which is now 19 years old and it's certainly uncomfortable heat and the variable speed air handler runs noisy fast all the time. My shop is heated and cooled with a mini split which is night and day better.

This is really good information to consider. When looking at replacing our older natural gas furnace and central air system, it looked like a similar system made the most sense. Solar could negate much of our electric costs, but the ROI was at least 11 years.

If the furnace + AC was replaced now, a heat pump plus electric furnace might make sense. At that point we'd be using more electric overall and the ROI for solar might make sense.

One of my employees lives outside of Nashville TN in a home built last year. In last weeks cold snap there his heat pump could not get the house above 62.

Some years ago, I had a heat pump with gas backup. When the heat pump went into defrost, the whole kitchen would shake. Switched the controller to use gas backup only. Solved the problem.

Another problem with heat pumps is that ice can form on the blades then fly off and damage the coils.

More trouble than they are worth.

quote:

Originally posted by PASig:

quote:

Originally posted by Excam_Man:
Just how cold does it get in the UK?

It can get quite cold there, I'm not so certain that heat pumps are going to really work there even with the advances they have made in recent years.

So you don't know the temps for the area and you're not certain they'll work...

Might as well condemn those damn HP's though, they just don't work in cold climates!

quote:

Originally posted by Graniteguy:
One of my employees lives outside of Nashville TN in a home built last year. In last weeks cold snap there his heat pump could not get the house above 62.

Are you suggesting we condemn his HP for not heating his home?

There's a reason most heat pumps include a 'Emergency Heat' strip. My HP here in Florida includes a 10Kw (I think) emergency heat strip to pick up for the HP's inability to reach heating goals. And when that sucker is on, which is far more than I'd prefer when the temp drops below ~35 degrees, the electric meter spins like a fan.

Another question for the UK would be, where is all that additional electricity to run these HP's and emergency heat strips gonna come from when everybody converts over, and how reliable is it going to be when it gets really cold? Gas and heating oil is really reliable, regardless the temp or weather conditions.

quote:

Originally posted by Excam_Man:

quote:

Originally posted by Graniteguy:
One of my employees lives outside of Nashville TN in a home built last year. In last weeks cold snap there his heat pump could not get the house above 62.

Are you suggesting we condemn his HP for not heating his home?

No. Why do you ask?

quote:

Originally posted by Graniteguy:

No. Why do you ask?

Why mention it then?

quote:

Originally posted by Excam_Man:

quote:

Originally posted by Graniteguy:

No. Why do you ask?

Why mention it then?

Felt like it since it is relevant to the conversation of modern heat pumps and their capabilities in varied climates. Real life example.

I've noticed a few places around me with the mini-splits always have a HVAC truck in the drive on mornings the temps are in the single digits like today.

I'd be willing to bet they are not putting in the heat pumps Americans have been scammed with for years... but the newer mini-splits. These puppies can heat a specific area with outside temps down into the single digits. the ones we put in our house do not have any electric back up.

If I'm wrong then they are idiots.... then again one of the dirty secrets in heating an area is that doing it by first warming air is very inefficient....

quote:

Originally posted by Graniteguy:

Felt like it since it is relevant to the conversation of modern heat pumps and their capabilities in varied climates. Real life example.

It's only relevant to the conversion if you actually *knew* why it wasn't maintaining temperature.

Hint: it wasn't because of the cold snap or the fact its a HP.

quote:

Originally posted by Excam_Man:

quote:

Originally posted by Graniteguy:

Felt like it since it is relevant to the conversation of modern heat pumps and their capabilities in varied climates. Real life example.

It's only relevant to the conversion if you actually *knew* why it wasn't maintaining temperature.

Hint: it wasn't because of the cold snap or the fact its a HP.

How could anyone possibly know that based only on my post?