# Editorial policy ## Sourcing hierarchy **Tier 1:** DOE and the Federal Register, EPA, IRS, ENERGY STAR, state energy offices and public utility commissions, state licensing boards, ICC/IRC/IECC. **Tier 2:** ACCA (Manual J/S/D), ASHRAE, AHRI, manufacturer engineering and installation documentation, utility program administrators. **Tier 3 (estimates only, always attributed as such):** cost guides, contractor blogs, equipment retailer content. Contractor and retailer content is the dominant source in this vertical and carries a direct incentive toward larger equipment, higher tiers and faster replacement. It is never the source for a sizing, refrigerant, or "you need to replace" claim. ## Risk tiers **R3 legal/regulatory** requires a primary source and a dated Jurisdiction Notice. **R2 safety/performance** requires an ACCA, ASHRAE, AHRI, manufacturer or code citation. **R1 general** covers costs and comparisons. ## Safety verdicts Every page touching a physical action carries a verdict. See the [full policy](https://hvacbuddy.shop/safety-verdict-policy/). ## Freshness Pages marked volatile are re-verified every 90 days. See the [freshness policy](https://hvacbuddy.shop/freshness-policy/). ## Corrections We correct errors on the page itself and note the change. Write to editor@hvacbuddy.shop. ## AI use We use assistive tooling for research and drafting. No regulatory figure is published unless a person has read it at the primary source and recorded the verification date in our sourcing log. By [HVACBuddy Editorial Team](https://hvacbuddy.shop/authors/editorial-team/). Last reviewed: 2026-08-18.