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More info on Air Source heat pumps A2WHP

We see a huge interest in this product, a few more big name manufacturers entering the residential market.

Idronics 27 is our current issue with current data and some serious number crunching:)


A webinar on the topic next week. Also some fuel cost comparison simulations.

A key is low temperature distribution, consider that as you start tubing radiant from now on. It could be as simple as tighter tube spacing that gets you in the sweet spot.

Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream


  • Larry Weingarten
    Larry Weingarten Member Posts: 3,383
    @hot_rod , Good info. Thanks!

    Yours, Larry
  • Zman
    Zman Member Posts: 7,605
    This is by far the most comprehensive paper on air to water heat pumps ever written.
    I am wondering where the air to air units fall on the spectrum as far as efficiency at lower temps. I would guess they fall close to the curve for 110 degree water.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • clammy
    clammy Member Posts: 3,113
    I really wonder why serval ammonia systems never are seen in references to heat pumps and hydro ? The few geo systems I ve seen where mainly done for the rebates and because they did not want to see any units outdoors . Aside from mini split type inverter compressor tech all the geo that I ve seen used old school tube in tube condensers and single stage compressors some may use flat plates I think just to save space . I really was not impressed by any of it . As for eff # are electrical Grid looses for transmission in there figures . Not to sound negative on 2 notes I know a fractional circ pump will always use less electric then the smallest hermetic compressor and 1/2 or 3/4 hp indoor fan . Some may know that these types are systems have been around quite a while and never caught on because of the costs but when u add all the incentives then the number may work out but nothing is free and if it where not for the incentives that industry would be even smaller then it is and remember some one has to pay for the incentives that are given and it’s not the end user or manafactures it’s the rest of us who s tax money allows it , I know I stand on my own two legs with no help and feel industries must be able to do so and not enabled by others including the government to make it happen and eventually fold . Great ideas and technology but I feel it vastly out of reach for most non fantasy home owners who will suffer sticker shock but for a 5 million dollar home where they will recoup a excellent incentive it’s a no brainer . Excellent article very informative but remember w this new tech a proper install w attention to every detail w a proper start up and proper maintance instead of break and react service is key and that all is never free . Again I hope none of this is taken as negative but I wouldn’t want reality to be confused w negativity being I try to always tell the truth as I see it and have experienced it first time . Great article non the less always enjoy reading just about anything hot rod writes . I know my neck would hurt holding my brain up if it contained 1/16 of his knowledge thanks bob PS u all know I love stirring the pot up peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • hot_rod
    hot_rod Member Posts: 22,467
    edited July 2020
    For years I felt the same about HP and the cost or inefficiency of the grid, being ignored. But getting over two units of energy, closing on three out for every one in is hard to argue with as the numbers show.
    And this graph is at low fossil prices. Plug in LP or oil at 4 bucks, where it was a few winters back! I predict those days may return in our lifetime.
    Something like a refinery going down seems to give big oil an excuse to double prices, almost overnight. Electric rates seem lot more stable.

    I suppose the same could be said for oil or gas, unless you have a well on your property?
    I suspect plenty of tax payer dollars subsidize the fossil fuel industry, pipe line construction and litigation, oil spill clean up costs, etc. All energy has its hidden cost. Except sunshine :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream