My 1964 house in Marin County, CA is 2500sf and we are re-insulating the house and installing all new double-glazed lo-E windows. I have also installed all new roofing insulation. We have 4 bathrooms, 2 kids (5&2) and I have a wife who is always cold.
I am changing the forced air system to radiant and am having a conflict between my plumber (bidder #1) and another radiant heat sub (bidder #2). We are looking to install a natural gas high efficiency wall mounted boiler along with a 40 gallon indirect fired water heater.
Bidder #2 (much less than bidder #1) has suggested a Prestige Solo 110 (30k-110k Input modulation MBH & a net I=B=R MBH of 88k). He is basing his calc on approx. 20BTU's per sf for radiant.
Bidder #1 (very expensive - $12k more) is saying that the 88k BTU boiler is half the size necessary and that I need to install a Buderus GB-142 with approx. 180k BTU. He is using a calc. of 40-50BTU's per sf. He is saying that I will be able to take a 3 second shower with the Prestige unit when the radiant is used at peak.
Is anyone right in this situation?
Need help - I am a layman when it comes to this stuff!