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AC & Furnace Sizing Calculator

Estimate the heating and cooling capacity your home needs. Right-sizing matters — an oversized system short-cycles and wastes energy, while an undersized one struggles on peak days.

What Size AC & Furnace Do You Need?

Your local climate changes the heating and cooling load for your home. This estimate uses a national mixed baseline — for a location-specific result, open your state page. Enter your details for a quick sizing estimate (BTU, tonnage and a recommended SEER2 range).

Your estimated AC tonnage and furnace size will appear here.

Actual equipment sizing requires a professional Manual J load calculation. This tool provides a rough estimate for general informational purposes only and is not professional advice, a guarantee, or a quote. Results may not reflect your specific situation. Always confirm with a licensed HVAC professional before making any purchase or decision. See our Terms of Service for details.

Frequently Asked Questions

What size AC do I need?
As a rough guide, homes need about 20 BTU of cooling per square foot, adjusted for climate, ceiling height and sun exposure. Confirm with a professional Manual J load calculation.
How many tons is my home?
One ton of cooling equals 12,000 BTU. A typical 1,800 sq ft home needs roughly 3 tons, but climate and insulation change this — use the calculator for your specifics.

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