Affiliate disclosure.

Watson Consulting participates in the Amazon Associates program, in the Rakuten Advertising network, and in Housecall Pro’s referral program. When someone follows one of our links and buys or signs up, the partner pays us a percentage of that sale or a fee for the referral. Your price is the same either way — the commission comes out of the partner’s margin, not off the top of your order.

HVACDirect was the first partner on this site, from August to October 2026; its links were removed on October 14, 2026, and nothing on this site links there now. Every link that remains is labeled where it appears: Amazon Associates links (ductless and window equipment, dehumidifiers, thermostats and test instruments, never central systems), manufacturer links placed through an affiliate network such as Rakuten Advertising (Sensibo smart AC controllers; HeatAndCool.com central systems, heat pumps and mini-splits), and referral links for homeowner installer quotes or contractor business software, where we are paid for the lead or the signup rather than a sale. There is no paid placement, no sponsored review, and nobody pays to be mentioned in a guide.

• Every affiliate link is labeled where it appears. Not just on this page. If a link earns a commission, the sentence next to it says so.
• Links are marked rel="sponsored". That is Google’s convention for paid links, and it means they pass no search ranking value to the retailer.

This is the obvious worry with an HVAC tool that links to an equipment seller: does the calculator round your load up so you buy a bigger unit? It does not, and that is enforced in the code rather than promised in a paragraph.

• Separate module, no path in. The affiliate code lives in its own file. The calculation engine cannot import it, and an automated test fails the build if any affiliate string turns up in the calculation path.
• Nothing reaches a report. The same test scans every generated PDF for an affiliate marker. A report you hand a homeowner, a builder, or a plan reviewer has no shopping link in it, no referral code, and no mention of a retailer.
• Sizing is stated as a band, never a unit. The app tells you the Manual S capacity range your load allows. It never names one model, because naming one would be a recommendation, and we are not in a position to make one.
• The app lets you turn it off. Settings › Shopping Links removes the card from the results screen. The toggle syncs across your devices and nothing about the calculation changes.

Whatever you buy and wherever you buy it, size the equipment to a real calculated load per Manual S — not the other way around. That advice costs us money on the occasions someone follows it to a different supplier, which is roughly the point.

Questions about any of this go to mike@hvacloadcalculator.online and get answered by the person who wrote the code. See also the privacy policy for what the apps store and what never leaves your device.