The short version: every terminal spec, wiring behavior, and control setting on this site traces to a manufacturer document, a standards body, or a named industry publication. No unsourced specs, no guessing from “common practice.” Here’s how that’s actually enforced, and what’s covered so far.
What “verified” means here
Every fact we publish, a thermostat model’s supported terminals, a wiring convention, a control setting’s parameter name, is stored in a structured record with:
- The specific claim being made
- A source URL: a manufacturer spec sheet, an installation guide, a standards document, or a named industry body’s publication
- A source tier: T0 (the manufacturer or standards body’s own primary document), T1 (a recognized industry body such as AHRI, ACCA, ENERGY STAR, NEC, DOE, EPA, or NEEP), or T2 (a reputable secondary source, permitted but never sufficient alone for a safety-relevant claim)
- A verification date, so a stale record gets flagged for re-checking rather than sitting unreviewed indefinitely
A script checks every one of these records before it ships: is there a real URL, is the tier valid, is a safety-relevant claim backed by T0 or T1 (not just a secondary source), has it gone stale. If any of that fails, the content doesn’t publish.
Where the sourcing comes from
Manufacturer documentation (Honeywell, ecobee, Nest, Mitsubishi, and others, direct from their own install and product guides), DOE and EPA regulations (SEER2/HSPF2 standards, refrigerant handling rules), ACCA and AHRI standards (load calculations, equipment matching), and NEC electrical code. Where we’re citing a real professional’s judgment call rather than a spec, such as a load calculation, a refrigerant diagnosis, or electrical panel work, we say so and point you to hiring one. See how to hire an HVAC company.
Research and first drafts on this site are AI-assisted, then checked against the sourcing standard above and reviewed by our team before anything publishes.
What’s covered today
Thermostat wiring terminals (R/Rc/Rh, C, G, Y1/Y2, W1/W2, O/B, E, L, S1/S2, K, and the accessory terminal), five thermostat models in depth, eight HVAC system types (air-source and mini-split heat pumps, dual-fuel, geothermal, boiler/hydronic, millivolt, line-voltage electric, conventional gas/electric AC), common control settings (AUX-heat lockout, staging delta, upstage timer, setback recovery), and reference material on efficiency ratings (SEER2/HSPF2), electrical panel and circuit basics, and heat-pump cold-climate suitability.
We’re adding to this continuously. Where we don’t have a sourced answer yet, we say so rather than filling the gap with a plausible-sounding one.
Found an error?
If a spec on this site doesn’t match what you’re seeing on your own equipment or in the manufacturer’s own documentation, tell us. A wrong wiring claim can send someone to the wrong terminal. We’d rather hear about it and fix the source record than have it sit uncorrected.
