High-Temperature Air To Water Heat Pumps
I’m in Vancouver, BC, and currently spec’ing out a reno replacement to a heat pump, from an existing Viessmann combi-boiler feeding fin tube baseboards around the house.
While I recognize from the room-by-room heat loads and the fin tube heating capacities that fin tubes like running at higher temperatures (approx 2x capacity at 160F vs. 120F), what struck me when I started getting into the system and component specifications is that there is a distinct lack of high-temperature Air To Water Heat Pumps (ATW) systems in North America. By high temp, I mean anything above the 100F-120F typical for in-floor radiant.
For example, in Europe, Daikin still sells the Altherma, which can put out 80C (176F) for DHW, and up to 55C (131F) for space heating, to enable use of older higher-temperature radiators. Similarly, there are high-temperature ATW systems available in Japan.
According to the sales person I’ve been working with from Arctic, they are only now certifying a high-temp (140F) ATW system for Canada (due by November 2023).
What happened in North America? Where did the high-temperature ATW systems go? As far as I can find from Google searches, there seems to be traces of, for example, the Daikin Altherma in North America perhaps a decade or so ago, but it is currently unavailable in North America.
Was it cost? Or the general lack of hydronic baseboard systems in North America vs. central forced-air ducted systems? Or was there some reliability issue which caused installers to back away from ATW here?
I’m hoping someone on this site could provide some insight on this, as reliability is one of the metrics I’m using to decide between ATW vs. ATA (typical, common mini-split which seems to be everywhere in North America right now).
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