Contact HVAC Tools.

Several shipped changes started as a one-line email from a technician who got a result that did not match the job. If a calculation looks wrong, the fastest path to a fix is an email that includes the inputs, so the same case can be reproduced here before the next build.

• Which app or tool. HVAC Load Calculator (US Manual J), Heat Pump Sizing Canada (CSA F280-12), Static Pressure & Duct Check, A2L & EPA 608, or one of the free browser calculators.
• The inputs you used. ZIP or postal code, square footage, insulation and window choices, duct run details, refrigerant and line set, whatever the tool asked for. A screenshot of the input screen works.
• What you expected instead. A manufacturer chart, a stamped design, or a number from other software is the most useful comparison, because it shows which assumption differs.
• Phone and app version. Device model, iOS or Android version, and the app version from the Settings screen. Crash reports without this are hard to trace.

Store reviews are read, but a review cannot be answered with a question, so an email gets a faster fix. If you have already left a review describing a problem, sending the same report by email lets us close the loop.

Subscriptions and one-time purchases are handled by the App Store and Google Play, not by this site. To cancel, change a plan, or request a refund, use the store that billed you. Apple purchases are managed in Settings › Apple Account › Subscriptions on the iPhone, and Google Play purchases under Payments & subscriptions in the Play Store app. If a purchase did not unlock in the app, email us with the store receipt date and we will sort it out.

Team plans for the HVAC Load Calculator are covered by the team terms. Questions about seats, invites, or a shared project library can go to the same address.

• Press and citations Logos, screenshots, app facts and a citable climate data file are on the press page. Interview and quote requests by email.
• Privacy requests What each app stores is in the privacy policy. Requests to see or delete account data for the team plan are handled by email, usually within a few days.
• Advertising and affiliate links How partner links and ads on this site work, and which ones pay a commission. Partnership proposals are welcome by email; paid placement in the calculators is not offered.
• Corrections to a guide If a guide cites a figure or a code reference that has changed, send the source and the guide will be updated with a dated note.

Mail is answered in English. Canadian users can write in French; replies may take a little longer. The shop is based in the United States and keeps normal North American business hours, so a message sent on a weekend is usually answered on Monday.