Heat Pump with Radiant Floors?
I’m wondering if anyone out here in eco Berkeley land has successfully installed a heat pump to run their radiant heating system. Currently we have a gas water heater that heats the water in the Pex in the floors. It seems like the larger HVAC companies don’t want to do anything that involves heat pumps and water systems. We have talked to a small shop who said he could do it but it seemed rather experimental territory. Wondering if anyone has done this successfully and has any advice or wisdom or recommendations to share? Thanks so much!!
Sep 23, 2022
Parent Replies
Hi!
Yes, there aren’t a lot of companies offering this service. We’ve used this company and I do recommend them for install and repair. https://albertnahmanplumbing.com
We are in the process of investigating getting a heat pump to run our hydronic radiant system, and have talked to several contractors. There are some innovative companies producing heat pumps for use with hydronic radiant. The ones we know of are Harvest Thermal, Sanco, and FlowTech. Some of these are also "chillers" in that they can provide cooling via floors as well.
As yet, it is hard to find contractors who are working with these brands because they are relatively new. Harvest Thermal seems particularly innovative but doesn't seem have many installers yet. The Sonoma Energy Center (run by Sonoma's utility) displays some of these brands of hydronic heat pumps. I hear East Bay Community Energy is setting up a similar site in the east bay but don't know when it will open.
Once we find a contractor, we're looking forward to getting rid of an old gas boiler that powers our radiant (which is a combination of staple up PEX and embedded in slab), and using only our solar PV to run the heat.
The old-fashioned HVAC people mostly seem to sell "ducted" heat pump systems (i.e., mini splits), which make no sense if you have radiant hydronic that you want to keep, as the whole point is that it is non-ducted and runs on water. You need a water source heat pump to run it, not an air source heat pump.
Heat pumps are much more efficient that a traditional gas boiler. Separately from our existing radiant heating, we already have a heat pump water heater for domestic hot water and it saves a lot. If you have an older gas or electric water heater, you might also want to check out combining it with your radiant project. (Or you can get a domestic water heat pump separately - PG&E has rebates for domestic water heat pumps here: bayren.org).
The new climate bill which will provide financial support for heat pump upgrades, and electric panel upgrades too. Rewiring America, a nonprofit, has an introduction to what kinds of tax credits and rebates here (most start after January 1): https://www.rewiringamerica.org/app/ira-calculator
Another source of information about using heat pumps for radiant is Redwood Energy's manual here: https://redwoodenergy.net/all-electric-retrofits/
Feel free to message me if you'd like to exchange ideas.
My understanding with radiant floors is that if you run chilled water through floors, that can condensation on floor surface, which may not be great. Would love to find out your actual experience with selecting and replacing your boiler with a heat pump!