Anybody installed an A-W heat pump yet?

[maple1]

No upgrades done here yet since we installed the two Daikin mini splits on the north end of the house 4 years or so ago. South end is iffy, when trying to get by on those as much as possible. Had been thinking we'd get another mini for the other end of the house. But A-W is intriguing. Been browsing the Arctic website. Made in Canada, seem legit. No refrigerant piping so easy DIY. Could also utilize to heat dhw. Could maybe also zone to a couple fan coils in a couple upstairs bedrooms. I have a 100 gallon LP tank taking up space in my basement that could be a buffer. But would really like to see and hear some real world feedback.

 

[peakbagger]

Not yet, still hoping for some main stream manufacturers to start selling. Tom in Maine (A hearth member) imported some quantity several years ago and was reselling them, so he may be able to give you a review.

Taco is importing German units but they appear to be selling an entire system of indoor and outdoor units.

 

[Highbeam]

I too am waiting for the tech to become available and established. Have a cold slab full of radiant tubing and a big circuit ran for it just waiting. I did jump on the mini split train this year for the house, been happy with that.

 

[EbS-P]

Someone has to be first. Finding the right installer would be very important. I’m not going to be first nor do I have the best application.

 

[begreen]

I too am waiting for the tech to become available and established. Have a cold slab full of radiant tubing and a big circuit ran for it just waiting. I did jump on the mini split train this year for the house, been happy with that.

Have you tried it out in below-freezing temps? I'm curious about how it will work out then, even if just for testing's sake.

 

[brenndatomu]

Isn't that what HPWH's are?

 

[woodgeek]

Isn't that what HPWH's are?

HPWHs have a tank and are designed to pump heat from around room temp to about 120°F, with a COP of about 3. They can't generally take outdoor air bc they don't have defrost controls, and instead shut down when the intake air reaches about 40-45°F. Their tonnage is also not that high (closer to 1 ton or less I think) and not adequate for space heating. Nor designed for that heavy of a duty.

 

[woodgeek]

I am personally skeptical that we will ever see mass adoption of A/W heat pumps for space heating in the US. Not a lot of low-temp hydronic radiation in the US. And given the need for AC in most US climates, I don't see it becoming more popular in the future. The old fad of in-floor heating is waning as envelopes get better insulated (lowering service temps on the floor, and making response times very slow/long).

Ofc, the EU has the opposite problems, so I am sure y'all can import some equipment from them if you want to mess around.

 

[brenndatomu]

HPWHs have a tank and are designed to pump heat from around room temp to about 120°F, with a COP of about 3. They can't generally take outdoor air bc they don't have defrost controls, and instead shut down when the intake air reaches about 40-45°F. They tonnage is also not that high (closer to 1 ton or less I think) and not adequate for space heating. Nor designed for that heavy of a duty.

Right...I get that...but other than scaling up and changing a few details, they are more or less an A-W heat pump, no?

 

[peakbagger]

John Siegenthaler the hydronics guru is big fan of these units but his focus is new installations. He especially likes that an A-W heat pump has reversing valves to produce cooling. The thing most folks are confused by is that A-W cooling pumps cold water to local terminal units rather than duct work. It is not much of a step to consider going all the way variable refrigerant flow systems that dispense with water and moving refrigerant around which is the way some commercial installations are going.

I have reviewed several geothermal installations for large school complexes and apartment buildings, they use the same heating and cooling distribution as A-W but replace the A-W outdoor unit with geothermal wells. These installations have one major common thing, they are publicly funded with less concern on first cost and the state funding it is requiring non fossil HVAC.

 

[EbS-P]

Right...I get that...but other than scaling up and changing a few details, they are more or less an A-W heat pump, no?

I think the heat exchanger in the AW units is more complex. The HPWH just wrap the hot side tubing around the tank and wait. The AW units need considerably more complicated thermal exchange management. But the concept is the same. It’s the application after the compressor that’s different.

 

[Highbeam]

Have you tried it out in below-freezing temps? I'm curious about how it will work out then, even if just for testing's sake.

The mini? Yes, ran it overnight when we were in the upper 20s about a week ago for a test. Only set to 73 and it had no problem keeping up. The family was not thrilled with 73 since we normally keep a 78 degree stove room but I was trying to be a normal residential user. I never saw the outside unit frost up but it definitely would drip water so it must have been doing some condensation management. Total cost for the 24 hours was under 2$, about 15 kWh more than the previous 24 hours. I feel like the outside unit is quieter in heating mode.

 

[maple1]

The mini? Yes, ran it overnight when we were in the upper 20s about a week ago for a test. Only set to 73 and it had no problem keeping up. The family was not thrilled with 73 since we normally keep a 78 degree stove room but I was trying to be a normal residential user. I never saw the outside unit frost up but it definitely would drip water so it must have been doing some condensation management. Total cost for the 24 hours was under 2$, about 15 kWh more than the previous 24 hours. I feel like the outside unit is quieter in heating mode.

What exactly did you get?

 

[maple1]

I am personally skeptical that we will ever see mass adoption of A/W heat pumps for space heating in the US. Not a lot of low-temp hydronic radiation in the US. And given the need for AC in most US climates, I don't see it becoming more popular in the future. The old fad of in-floor heating is waning as envelopes get better insulated (lowering service temps on the floor, and making response times very slow/long).

Ofc, the EU has the opposite problems, so I am sure y'all can import some equipment from them if you want to mess around.

I think they have potential. It can be done all DIY, since there is no refrigeration work needed, and you can put fan coil units almost anywhere - just need to run some pex to them. One outside unit, several inside ones. All individually zoned. And they can do a/c in the summer, and heat your DHW. Mini splits can't do all that.

 

[begreen]

The mini? Yes, ran it overnight when we were in the upper 20s about a week ago for a test. Only set to 73 and it had no problem keeping up. The family was not thrilled with 73 since we normally keep a 78 degree stove room but I was trying to be a normal residential user. I never saw the outside unit frost up but it definitely would drip water so it must have been doing some condensation management. Total cost for the 24 hours was under 2$, about 15 kWh more than the previous 24 hours. I feel like the outside unit is quieter in heating mode.

Thanks for the update. That sounds pretty good.

 

[Highbeam]

What exactly did you get?

I put in a DIY mrcool 24k single head mini split in my 1700 sf 1963 built home that had no ducts and that I have been hearing 100% with wood since 2006. The DIY kits are like connecting hydraulic lines on a tractor.