Affiliate disclosure.

Watson Consulting participates in the affiliate program run by HVACDirect.com. When someone follows one of our links and buys, HVACDirect pays us a percentage of that sale. Your price is the same either way — the commission comes out of the retailer’s margin, not off the top of your order.

That is the entire program. There is no second partner, no paid placement, no sponsored review, and nobody pays to be mentioned in a guide. If that ever changes, it gets written here first.

• 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.
• Referral code BZ07T66Q4DVJ does the same job as the link. Entering it at checkout credits the referral to us. It does not change your price, and it works even if you come back days later on a different device.

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.