About

HVAC Calc Hub is an independent reference site for people who want to understand heating and cooling numbers before they sign a quote. It is written for homeowners, landlords and the technicians who explain things to them.

How content is produced

• Calculations follow published methods: ACCA Manual J/S/D for loads and ducts, ASHRAE Fundamentals for psychrometrics, DOE test procedures for efficiency ratings, and manufacturer data for refrigerant properties.
• Every calculator shows its formula and the assumptions it makes.
• Pages are reviewed and dated; the review date is shown at the bottom of each one.

What we don't do

We do not sell equipment, take referral fees from contractors, or run pop-ups. Estimates here are for planning; final sizing and any work on refrigerant, gas or high-voltage circuits belongs with a licensed professional.