ComfortSizer makes free calculators that answer one practical question: what size air conditioner, heater or other home comfort equipment do I need?
Most sizing advice online is either a one-line rule of thumb or a sales funnel that asks for your phone number. We wanted something in between: a tool you can use in seconds, that shows its math, and that never asks for your details.
How we build the calculators
- Published sources first. Cooling sizes come from the ENERGY STAR room air conditioner sizing chart and its official adjustments. Heating estimates use the climate-zone rule of thumb HVAC contractors use for quick sizing, and we say so on the page.
- Show the math. Every result has a "How we got this number" breakdown so you can check each step.
- Private by design. The calculations run in your browser. Nothing you type is sent to us.
- Honest limits. Room calculators are estimates. For a whole-house central system, we tell you to get a Manual J load calculation from an HVAC professional.
Contact
Spotted an error or have a suggestion? Write to hello@comfortsizer.com.