Contact

Write to [email protected] with questions, corrections or ideas for new calculators.

What to write to us about

• A result that looks wrong. Tell us which calculator you used and what you entered. A wrong formula or a wrong example is the most useful thing you can report.
• A figure that is out of date. Prices and efficiency levels change. Every figure on the site shows its source and the date we last checked it, so a link to a newer official table helps us update it.
• A question about how a number is calculated. Each calculator explains its formula, and the methodology and sources page lists every data set. If something is still unclear, tell us where.
• An idea for a calculator or a guide. We build tools that answer one specific cost or sizing question and cite where their numbers come from.

What helps us answer

• The address of the page you are writing about.
• The numbers you entered and the result you expected.
• The source of any figure you think is wrong.

What we cannot do

We cannot give personal advice on equipment, installations, solar panels or energy contracts, and we cannot size a system for your home. The calculators give estimates, and a licensed professional should confirm any decision about wiring, fuel or equipment. See thedisclaimer for the details.

We do not take payment to change a result or to recommend a product. If you write to us, we use your message and your address to answer you. The privacy policy explains how the site handles data.