Contact

The fastest way to reach us is email: [email protected]. A person reads every message.

What helps in a message

• Calculation errors: the page address, the exact inputs, the result you got and the result you expected, with its source if you have one.
• Feature requests: the question you were trying to answer. The next tools planned are window AC, mini-split, furnace size, CFM, BTU-to-ton and attic insulation calculators.
• Your own HVAC project: we can point you to the right tool or table. We cannot size equipment for a specific house remotely or review a contractor's Manual J.

Before you write

Many sizing questions are answered on the tool pages themselves: the FAQ at the end of each calculator covers the common ones, and the methodology page lists every formula and source. If a result looks off, try the same inputs on the page again and note which step under the readout seems wrong. That step is usually the fastest way for us to find the problem.

We usually reply within a few working days.