Our standards
This policy explains how HVACrly researches, writes, fact-checks and updates its HVAC and water heater guides and calculators.
At a glance
- Written and reviewed by David Clark
- Manufacturer manuals and official standards as primary sources
- Safety risks clearly flagged
- Errors corrected and updates dated
Who Writes Our Content
Guides are written and reviewed by David Clark, founder of HVACrly, who has more than 10 years of experience with residential and light-commercial HVAC systems. Every guide shows its author, publication date and the date it was last updated.
Sources We Use
- Manufacturer installation manuals, use & care guides, spec sheets and error-code documentation
- Industry standards and methods, such as ACCA Manual J (load calculation) and Manual D (duct design)
- Government and energy-efficiency resources, such as the U.S. Department of Energy, ENERGY STAR and the EPA
- Real-world professional experience on residential and light-commercial systems
When manufacturer instructions differ from general advice, we follow the manufacturer and say so.
Our Fact-Checking Process
- ResearchIdentify the exact product, model range or system and gather official documentation.
- WriteExplain what to check, in what order and what each result means, in plain language.
- Safety ReviewFlag steps involving gas, high voltage, refrigerant, venting or scalding water.
- UpdateRevisit content when models, codes or efficiency standards change.
Safety Standards
- We tell readers to turn off power, gas and water before working on equipment.
- We don’t give instructions for work that legally requires a licence or certification, such as handling refrigerant (EPA Section 608 in the US).
- We recommend a licensed professional for gas, electrical, venting and combustion work.
- We remind readers that local codes and permit requirements vary.
About Our Calculators
Our calculators give estimates based on the inputs you provide and common industry methods. They’re designed to help you understand your system and ask better questions — not to replace a full load calculation, duct design or on-site assessment by a qualified contractor.
Use of Tools & AI
We may use software tools, including AI-assisted tools, to help organise research or prepare drafts. Every guide is reviewed, fact-checked and edited by a person before publishing, and HVACrly takes full responsibility for what we publish.
Corrections & Updates
If you spot an error, email [email protected] or use our contact form. We review every report, correct verified errors promptly and update the “last updated” date when we make meaningful changes.
Editorial Independence
Manufacturers, advertisers and affiliate partners don’t review or approve our content before publication and don’t influence our recommendations. See our affiliate & advertising disclosure.
Found a Mistake?
Corrections help keep every guide accurate and safe.