The HVAC tools contractors actually use.
Size your system, compare costs, plan ductwork, check refrigerant. Free tools built by licensed techs. No logins, no math by hand.
- Categories
- 6
- Built by techs
- Licensed
- Avg time per tool
- 90 sec
Six categories
Every HVAC question, sorted.
From basic sizing for homeowners to refrigerant math for pros. Pick a category to see what is inside.
System sizing
Get the right tonnage. Stop oversizing.
ExploreCost & ROI
Real numbers, real bills, real payback.
ExploreEfficiency
Decode the ratings that actually matter.
ExploreDuctwork & airflow
Free duct math that used to cost $400.
ExploreRefrigerant
R-410A, R-32, R-454B. All the math.
ExplorePro tools
For technicians and serious DIYers.
ExploreHow these calculators get built.
The math comes from ACCA Manual J, NEC Article 440, ASHRAE handbook tables, and manufacturer engineering data. Every tool is reviewed by a licensed HVAC tech who works the relevant trade every day.
01
Inputs that match a real job
Climate zone, insulation R-value, window orientation, ductwork condition. The fields are the same ones a contractor would write down on a load sheet before quoting you.
02
Reviewed by working techs
Each calculator credits the reviewer by name and trade certification on the page. Marcus on refrigerant work, Tom on duct, Jen on the electrical side. The roster lives on the about page.
03
Results you can hand a contractor
Each output tells you what the number means, the code or formula behind it, and what to verify before signing a quote. Useful on a service call, useful on a kitchen table.
Stop guessing. Start sizing.
The BTU sizer takes 90 seconds and gives you a number you can show your contractor.