help i think - Contractor Talk - Professional Construction and Remodeling Forum

benchmark2323 · 01-15-2007, 05:20 PM

hvac is not my trade so bear with me please. i just built a house and had to use a new hvac guy. he priced me a 80% bryant furnace with 55000 btu. this home is 1750 sq.ft with 2 - 15' cathedrall ceilings. is this a big enough furnace there are 3- 4x12 returns in the bed rooms (1 in each rm)and 1 16"x16" in the living rm. the living rm and the master bed have the vaulted ceilings. hopefully this is enough info. anyway i was wondering if this is enough of a furnace for the home. i have 2x6 walls with the blown in blanket and roughly an r-40 in the ceiling ( blown-in) any info would help thanks in advance

AirPro · 01-15-2007, 07:35 PM

Quote:

Originally Posted by benchmark2323

hvac is not my trade so bear with me please. i just built a house and had to use a new hvac guy. he priced me a 80% bryant furnace with 55000 btu. this home is 1750 sq.ft with 2 - 15' cathedrall ceilings. is this a big enough furnace there are 3- 4x12 returns in the bed rooms (1 in each rm)and 1 16"x16" in the living rm. the living rm and the master bed have the vaulted ceilings. hopefully this is enough info. anyway i was wondering if this is enough of a furnace for the home. i have 2x6 walls with the blown in blanket and roughly an r-40 in the ceiling ( blown-in) any info would help thanks in advance

He should have done a manual J heat load calculation to properly size the equipment. If he hasn't... find another hvac guy that does it right, this is no place for guessing or rule of thumb calculations.
Here in Florida, you won't get pass plans review to even pull the master permit without one.

benchmark2323 · 01-15-2007, 09:16 PM

how do you figure the heat load calculation

#CARRIERMAN · 01-15-2007, 09:26 PM

Hi benchmark2323

If you are a ACCA member its pretty easy to get this information. To do the calculation it will ask you windows, construction ,climate , etc. AirPro is dead on accurate, if he did not do this he needs to be fired. You may be able to go online to a ACCA site and download the manual J. Many things have changed since I got mine. One of the other guys may be able to tell you where to get it also.

Good luck
Rusty

AirPro · 01-16-2007, 08:16 PM

http://www.wrightsoft.com/order/look...y=US&pid=RSR(J)

That is what I use to get the #'s, I then do the duct design and layout using a ductulator. You can buy the manual D add on to do this for you, but I couldn't justify the added cost to replace something I have been doing by hand for years.
There are also people that do these for a living, so if you won't be doing it more than once, you can just pay a certified energy rater the $150- $200 to do it for you....Or find an HVAC contractor that is professional enough to to the job right and include it in his bid.

Good luck!.