HVAC Size Calculator
Find the right AC or heating system size for your home in 60 seconds. No signup required.
Tell us about your space
Just the area you want to cool/heat
How to Size Your HVAC System
Choosing the right size HVAC system is critical. An oversized system cycles on and off too frequently, wasting energy and failing to dehumidify. An undersized system runs constantly and never reaches comfortable temperatures.
The Basic Rule of Thumb
The general rule is 20 BTU per square foot for cooling. However, this varies significantly based on climate, insulation, sun exposure, ceiling height, and other factors — which is why our calculator adjusts for all of these.
Why Professional Sizing Matters
While our calculator provides a solid estimate, a professional Manual J load calculation considers additional factors like window orientation, ductwork condition, and local weather data. We recommend getting at least 2–3 professional quotes with proper load calculations before purchasing.