âī¸ AC Unit Size Calculator
Find the right air conditioner size for your home. Get tonnage, SEER rating recommendations, and estimated annual energy costs.
How to Use This Calculator
Start by entering your home's total square footage. Adjust the ceiling height if it differs from the standard 8 feet. Select your insulation quality and climate zone. Indicate the number of stories in your home and your sun exposure level. The calculator instantly shows your recommended AC unit size.
Understanding Your Results
Tonnage is the standard measure for AC unit sizing. Getting the right size is critical â an oversized unit will short-cycle and fail to dehumidify, while an undersized unit will run constantly. The SEER range recommendation helps you balance efficiency and cost. Higher SEER ratings cost more upfront but save money on energy bills over the life of the unit.
Frequently Asked Questions
What size AC unit do I need for my house?
AC size depends on square footage, insulation quality, climate zone, ceiling height, and sun exposure. A rough guide: 1 ton per 400-600 sq ft in moderate climates. Our calculator gives a precise recommendation.
What SEER rating should I look for?
The minimum SEER rating is 14-15 depending on your region. Higher SEER (16-25+) means better efficiency and lower operating costs, but higher upfront cost. 16-18 SEER is a good balance for most homeowners.
Can an AC unit be too big for my house?
Yes! An oversized AC will short-cycle, turning on and off frequently. This wastes energy, increases wear, and fails to properly dehumidify your home. Proper sizing is essential.
How much does it cost to run an AC unit?
Operating costs depend on unit size, SEER rating, electricity rate, and usage hours. Our calculator estimates annual energy costs. Use our Energy Cost Calculator for detailed breakdowns.