Bad HVAC advice on the internet is not a nuisance — it puts people on ladders they should not be on and inside burner compartments they should not open. This page documents exactly how content on Repair or Call is produced, so you can judge whether to trust it.
How we research a guide
Every diagnostic article is built from four kinds of source, in this order of authority:
- Manufacturer service literature. Installation and service manuals, sequence-of-operation charts, and diagnostic flash-code tables from Carrier, Trane, Lennox, Goodman, Rheem, A.O. Smith, Bradford White and the other major residential brands. Where a fault code or a spec is quoted, it comes from the manual, not from a forum.
- Codes and standards. The relevant sections of the International Residential Code, NFPA 54 (National Fuel Gas Code), and EPA Section 608 rules for refrigerant handling. We flag where local amendments commonly differ.
- Field experience. The order in which causes are listed reflects how often each one turns out to be the fault on actual service calls, not how interesting it is to write about.
- Contractor pricing data. Cost ranges are built from our contributors' own invoice history plus quotes collected from independent contractors across at least eight US metro markets, spanning low-cost and high-cost labor regions.
How pricing is calculated
Every figure on this site is an installed price in US dollars — parts plus labor plus the contractor's margin — unless the table says otherwise. We publish a low and a high rather than a single number because the spread between a rural market and a coastal metro is real and hiding it would be dishonest.
Ranges assume normal business hours and a straightforward job. Emergency, after-hours and weekend rates typically run 20% to 40% higher, and we say so where it matters. We do not accept payment from contractors or manufacturers to adjust a published range, and we do not use pricing supplied by lead-generation partners.
Who reviews it
Nothing publishes on a diagnostic or safety topic without review by a credentialed tradesperson — for HVAC and water heating, that means an EPA 608 certified technician with active field experience. The reviewer's name, credential and profile link appear on every article byline, and clicking through shows every other article that person is responsible for.
Reviewers check three things specifically: that the cause ordering matches field reality, that no step instructs a homeowner to do licensed work, and that every safety threshold in the article is where a professional would actually draw it.
Safety thresholds
We use one consistent rule. If a task requires breaking a gas connection, opening a sealed refrigerant circuit, working on the line side of a disconnect, or evaluating a heat exchanger, the article says call a pro — regardless of how many videos exist showing otherwise. Articles touching gas or line voltage carry a safety notice above the content, not buried at the bottom.
Updates and corrections
Every article is reviewed at least once a year, and cost tables are re-priced annually against fresh contractor quotes. The Updated date in each byline reflects the last substantive review — we do not touch a date to look fresh to a search engine.
Articles are also updated outside that cycle when a code changes, a manufacturer issues a service bulletin, or a reader shows us we got something wrong. Corrections to a material fact are made promptly and, where the correction changes the advice, noted in the text.
If you believe something here is wrong, write to editorial@repairorcall.com. Corrections from working tradespeople go to the front of the queue.
Independence from advertising
Repair or Call is funded by display advertising, contractor referral fees, and affiliate commissions. Editorial decisions are made without reference to any of it. Advertisers do not see content before publication, cannot request changes, and cannot buy a mention. Products named in an article are named because a reviewer would use them.
On generative AI
AI tools may be used for outlining, formatting and copy editing. They are not used to generate diagnostic sequences, safety guidance or price ranges, and no article publishes without a human tradesperson having read it end to end and signed off.