HVAC Size Calculator
Find the right size air conditioner, heat pump, or furnace for your home. Don't overpay for too much unit or suffer with too little.
Total area you want to heat/cool. Don't include unfinished basements or garages.
Your HVAC Size Recommendation
Estimated Equipment Cost (2026)
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What Size AC Unit Do I Need for My House?
Choosing the right HVAC size is one of the most important decisions you'll make for your home comfort. The general rule of thumb is 1 ton of cooling capacity per 500-600 square feet, but this varies significantly by climate zone, insulation quality, and home characteristics. Our calculator uses a modified Manual J calculation method to give you an accurate recommendation.
Why HVAC Sizing Matters
An undersized system will run constantly, struggle on hot days, and drive up your energy bills. But oversizing is just as bad — an oversized AC unit will short cycle, turning on and off too frequently. This prevents proper dehumidification, creates uneven temperatures, wastes energy, and shortens the equipment's lifespan. Getting the right size means lower bills, better comfort, and equipment that lasts 15-20 years.
HVAC Tonnage Chart by Square Footage
For a moderate climate with average insulation: 600-1,000 sq ft needs 1.5 tons, 1,000-1,500 sq ft needs 2-2.5 tons, 1,500-2,000 sq ft needs 2.5-3 tons, 2,000-2,500 sq ft needs 3-3.5 tons, and 2,500-3,500 sq ft needs 3.5-4 tons. Hot climates add 0.5-1 ton, while well-insulated homes can subtract 0.5 tons.
Central AC vs. Heat Pump: Which Should You Choose?
Heat pumps cost 20-40% more upfront but provide both heating and cooling, and they're significantly more efficient in moderate climates (Zones 2-4). In very cold climates (Zone 5), you may still need a furnace backup. Many states also offer heat pump tax credits and rebates of $2,000-$8,000 through the Inflation Reduction Act, making them increasingly cost-competitive.