Radiant floor heating, Boiler vs. Air to Water Heat Pump
Hi all, first time poster, but have gotten some great advice from this site during my project. I finally signed up and decided to post regarding a question about how to heat my radiant floor as we move fwd on my home build. First a little background on my project.
Our house is a 2300 sq/ft 3 bed/ 2.5 bath, single level home located in Parkdale OR, with what looks to be zone 5 climate. We typically get a good solid several month run of temps around the low to mid 30’s with several weeks that will drop into the teens or single digits depending on temp.
Our housebuild has tried to balance cost efficency with whatever energy upgrades that we can afford to integrate and has somewhat followed a “pretty good house” model. Heating will be entirely in floor radiant floor concrete slab heating, and we have wrapped all walls with 2″ of polyiso. Windows are vinyl double pane low-e (can’t remember exact U values right now) with solar defense coating. The main part of the house is a 24×48′ two story space with a loft and cathedral ceilings (8/12 upper cord, 4/12 lower cord scissor trusses with a 12″ energy heel), and the bedroom wing is a 14×52′ single stor with a 4/12 catherdral ceilings throughout. Ceiling insulation will be R-49 in most of the main living space, and R-38 cathedral batts in the bedroom wing. Underslab we have R-15 of XPS foam with 2″ of foam at the perimeter of the slab. The whole house has been pretty carefully detailed to manage air infiltration, but is clearly not up to a passivhouse standard….just trying to go a little above and beyond basic construction code and be a little more efficient than a normal prescriptive home.
My question revolves around a quote I just recieved from the company that designed our radiant system and performed heat load calcs/ etc. They originally had spec’ed an Argo electric boiler for the project, but just informed me that for an extra 3,300 dollars we could convert to a (as yet unspecified brand) air to water heat pump which the company claims will dramatically lower cost to operate our radiant system. Right now the system is three zone (main living area, master suite, guest bedrooms) and I assume that the company is factoring in boiler/ heat pump sizing according to all of their prjected heat load calculations that they performed when designing the system.
At this point, I would like to hear pro’s/con’s of air to water heat pumps and electric boilers as I have had a devil of a time finding much info on air to water installs as they seem to be in their infancy in the US. We are building the house ourselves and at this stage 3,300 dollars extra added on to the budget has the potential to be significant, but do-able if we will see good long term cost savings with the heat pump. We will also b subbing out install of our final radiant controls and need to factor any changes in cost for install into the budget.
I appreciate any info or thoughts that you guys have on this matter, thanks for you time.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part