About ClimateCalcs
ClimateCalcs is an independent project with one goal: to gather the everyday calculations homeowners, DIYers and system buyers reach for across the whole heating & cooling decision — sizing, running cost, efficiency, fuel switch, replacement budgeting and comfort — in one focused, free, no-signup hub with transparent formulas.
Who is behind it
Author and curator
To be clear about credentials: I am the author and curator of this site — not a licensed HVAC contractor, NATE-certified technician, EPA-608 tech or professional engineer. What I bring is relevant and real: building deterministic online calculators (open-source Python projects) and engineering training, i.e. rigor on thermodynamics, psychrometrics and heat-transfer math. That is what it takes to curate a hub of calculators: transparent method, correct formulas, cited constants and worked examples.
Our principle: transparent & durably correct
Every calculator shows its formula, a worked example and a reference table. The tools rest only on timeless building-science math and stable constants (1 ton = 12,000 BTU/h, 1 kWh = 3,412 BTU, 1 therm = 100,000 BTU, ~400 CFM/ton, ASHRAE 62.2 rates, the DOE 2023 SEER2/HSPF2 test basis). There are deliberately no energy prices, equipment prices or live feeds — cost tools use the rate you enter — so the results stay valid over time.
Correctness is checked against known reference values (see the methodology and the numeric self-check). The formulas and their sources are documented under Sources & formulas. All results are planning estimates: a professional Manual J / Manual S load calculation is required before buying equipment, and gas, electrical and refrigerant work must be done by licensed pros — install CO alarms. Questions? Use the contact page.