Proper sized heating unit?

nydoodles

I'm in the middle of an addition/renovation adding 1500 sq. ft. to my current 1500 (all single floor) in WNY. I will be removing my forced air unit and replacing with radiant heat throughout. Addition is 3/4 slab with a 288 sq ft. basement connected to my current full basement. My contractor has recommended a Peerless Purefire 4 (210,00 B.T.U.) unit. Seems a wee bit large to me... I haven't had a heat loss assessment made.

BobC

A detailed heatloss has to be done or it;s all guesswork.

Bob

Snowmelt

even if you did 50 BTU per square foot you only need 14,400.

nydoodles

Went to loadcalc.net and this estimated a 125,000 BTU requirement.

Rich_49

Never let him in your house again ! Traveled to Plattsburgh in Nov. 14' where the homeowner had a 145,000 BTU boiler , why so big ? Snowmelt ! That boiler is much too large for the house , roughly the same size home as yours after completion .

We had to add an 80 gallon buffer tank to calm the mod con down among other measures to actually melt snow and get ALL the upstairs rooms comfortable .

get a room by room heat loss done by someone or perform it yourself , you'll be amazed .

nydoodles

Rich and Snowmelt, Thanks for your comments. I'm scheduling a heat loss workup.

RobG

I don't know who will be doing your heat loss but I would recommend looking up Slantfin Heatloss Calculator and doing it yourself. You can post your results here and we can review and advise. 210,000 BTU's is INSANE for a 3000 Square foot home unless it has no insulation and is in the north pole!

Jamie Hall

Second, third, fourth... get that heat loss done. The place I care for is over 7,000 square feet, essentially uninsulated, and uses 300,000 BTU on a -10 F day. The boiler is rated at 385,000 BTU. Your 210,000 BTU has to be oversized.