HomeExpertly
www.homeexpertly.comFurnace Size Calculator
Estimate the furnace size for a home — area, ceilings, climate, insulation and windows — with the heating load, the input and output BTU by AFUE efficiency, a U.S. cost estimate, and a downloadable PDF.
This is a quick rule-of-thumb estimate — a contractor's ACCA Manual J load calc is what sizes real equipment. Oversized furnaces short-cycle and waste fuel. For planning purposes only.
Home & Climate
1
Heated Space
ft
×
ft
ft
+1k ea
sq ft
Length × width. Edit to enter total heated square footage.
2
Climate & Envelope
10%
A modest pad for the coldest days; big oversizing short-cycles and wastes fuel
3
Furnace & Cost
%
$
Furnace Estimate
Recommended Furnace
—
Enter your home to begin
Heating Load
—
Furnace Output
—
AFUE
—
Heating Load Estimate
Base load area x zone—
Ceiling adjustment—
Insulation factor—
Windows add—
Required output with margin—
Furnace input output / AFUE—
RECOMMENDED FURNACE—
BTU / sq ft
—
Required Input
—
Est. Install Cost
—
Heating Load By Zone
Heating load for your home, by climate zone
Climate Zone Comparison — Your Home
| Climate Zone | BTU / sq ft | Heating Load | Furnace Input |
|---|
For your 1,500 sq ft home at AFUE 95%. Colder zones and leakier homes need a bigger furnace.