Arctic Heat Pumps Air to Water Heat Pumps for Cold Weather!!

FInally a question! I presume its still the case that a separate heat pump for DHW is the right answer (I am considering an Arctic system for an in-slab radiant system in a cold climate)

Hi there, and congratulations and good luck on your new business!

We hear on this forum all the time that heat pumps can't handle new england (or even mid-atlantic) winters comfortably. I admit I am out of date with the current technology…is this still the case today for Air-to-Air or Air-to-Water?

The technology is there yes but, how many techs know how to work on them?

Hard enough to get a simple gas or oil tech, throw all these computers in the mix and that # drops dramatically!

hehe ok. So I guess if attacking the technology doesn’t work, we can attack the techs available (something that is an issue for all heating and cooling technology it seems). Got it!

Hi, Maybe these folks will have something to say about efficiency standards. 🤔 https://www.advancedwaterheatinginitiative.org/

Yours, Larry

It's based on measurement.

They measure actual output and energy consumption under a series of standardized conditions, varying both load and temperature. So every unit is compared on the same footing.

That's the main thing. They also have a cool feature where you can put in your zip code and design load and it will tell you how many hours per year to expect at each degree. From that they tell you how many hours your heat pump will be load low modulating, and if you need supplemental heat, how many hours a year of supplemental heat you would expect. It's an extremely quantitative answer to the question, "will a heat pump work in my climate?"

They also allow you to download the underlying data for both performance and hours per year at temperature. From that, you can estimate your load at each temperature, and the COP for your heat pump at that load and temperature. Multiply that by the hours per year at each temperature, and add them all up, and you get energy usage per year. Then take your local cost of electricity, and any other fuel, and you get the answer to the question, "will a heat pump save me money?"

I've never seen anything like it.

I'll second DCContrarian on the NEEP site and data. It provides the data that was missing before to make an informed decision about selecting a heat pump.

It is the only resource that tackles the issue with low load cycling which is one of the biggest killers of heat pump efficiency.

I don't know why. You'd have to reach out to them.

My understanding is the manufacturer has to provide both an outdoor unit and indoor unit for the test, they test the configuration as provided. So an air-to-water heat pump manufacturer would also have to provide an air handler.

I don't see any reason why testing a heat pump/air handler combination would be any different if the fluid running between them is water instead of refrigerant.

I think you were the one who turned me on to it originally.

And please don't think I'm picking on you. I think the Arctic unit will do very well in the NEEP testing. The point I was trying to make that while certifications like Energy Star are useless, serious people look at the NEEP database. The number one thing you could do to get your product taken seriously by the kind of people who are opinion leaders would be to get a performance profile into the NEEP database.

I have no idea how that happens. I know they have over 100,000 equipment configurations in their database so it can't be that hard.

OK, this gets to the issue of apples-to-apples comparison.

In the past, the claim was made that underfloor heat was more efficient, in that occupants of the space experience the same comfort with less heat being delivered. That claim has kind of gone out of style and the evidence to support it was always kind of sketchy.

What is true is that with underfloor heat you can use much cooler water, which with a heat pump allows for much greater efficiency, in terms of COP. You can reasonably run such a floor with water at 95F.

Now, you could also run an air handler with water at 95F, and I believe you'd see the same efficiency — measured by COP — as with underfloor. The issue you'd run into is it would have to be a big air handler, with a big fan. But it would get you into the NEEP database.

One thing I thought was curious was that the only performance numbers I could find on the Arctic website were for water at 113F, most air-to-water manufacturers push the 95F numbers because they move the performance curve 18F to the left, which looks a lot more impressive.

Also, on the Arctic website there is a line of hydronic fan coils from 3.6 to 14.3 kBTU/hr. The coolest water they provide ratings for is 113F.

I think this would be more productive if you sold homeowners on this and not us. There’s a disconnect here: this corner of the internet loves hydronics but the public doesn’t. Listen to what the customer is telling you and adjust.