What Size BTU Furnace Do I Need For This House? Need Help.....

Old 05-31-12, 05:07 PM
Thread Starter
Join Date: Feb 2009
Location: usa
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
What Size BTU Furnace Do I Need For This House? Need Help.....

I just bought a small rental house and want to install a different heating system.
It now has the old type natural gas floor furnace with the big register in the floor for heat. I want to install a New Natural Gas Forced Air Furnace with duct work.
I am unsure what size BTU furnace I need. I have been told everything from a 40,000 to a 100,000 btu furnace. Need help with what would be correct. I dont want an under sized or over sized system. This will be for Heat Only and not considering central air at this time. Here are the details on the house.
Small House:
750 square feet
Insulation Poor
New replacement windows
Natural Gas
Located in Central Kentucky lowest temps average 15-20 degrees in winter
House has basement and is one story
5 room house
Let me know what you guys think would be the correct size btu furnace.
Old 05-31-12, 06:50 PM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,491
Upvotes: 0
Received 8 Upvotes on 8 Posts
Only way to know is to do a heat load on the home.
Old 06-01-12, 01:01 PM
user 10's Avatar
Join Date: Mar 2004
Location: NA
Posts: 1,829
Received 57 Upvotes on 50 Posts
It's impossible to design a system without a room by room load calculation. Do not use anyone who refuses to do one.

You mentioned that the insulation is poor (post r-values if you know them); do everything you can to reduce heat loss prior to replacing the heating system. A high efficiency furnace is not a cure all for high energy bills.

- Air sealing and adding attic insulation can give a good return on investment.
- If your house has empty framed walls, it's possible to get densely packed cellulose (see Cellulose Dense Packing Insulation - YouTube) or foam injected into the wall cavities

Your house shouldn't need more than 50 000 BTUs unless there's no insulation, that's for sure.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: