We have new construction on a 4500' 5BD 3.5BA 2nd home in Northern California. Our HVAC sub is recommending an all-on-one Phoenix 199kBTU/119g propane-powered DHWH to heat our radiant floors and provide domestic hot water directly. Our 14 zone radiant is 60% in our concrete floor topping slab, 40% in gypcrete under hardwood or carpet.

Phoenix has only been briefly mentioned on these forums .. curious as to why.

With our PV array, we expect to near zero out our electrical bill at year's end so are reluctant to go 100% propane. I've seen suggestions on these forums to go with a low-mass boiler (Munchkin?) and separate electric DHW.

How much we would lower propane use by separating the DHWH? We may be bumping up against our electrical service ceiling .. not sure what an electric DHW connected load would look like.