Follow the sources.
Primary guidance, pinned datasets and transparent screening assumptions.
Primary data and technical guidance.
Sources were reviewed on October 1, 2026 unless a dataset gives an earlier retrieval date. Each result links its relevant sources. Our own multipliers are labelled as assumptions; source inclusion does not imply endorsement.
- Generac manufacturer wattage guidance — appliances_watts; retrieved 2026-10-01.
- PNNL climate and building research — climate_zones; retrieved 2026-10-01.
- Rinnai water-heating guidance — groundwater; retrieved 2026-10-01.
- ENERGY STAR sizing guidance — sizing_models; retrieved 2026-10-01.
- EIA electricity sales, revenue and price — consumption; retrieved 2026-09-27.
- PVWatts v8 API — genuine per-state representative-city responses; parameters and weather source shown in each result.
- PNNL-33270 climate-zone report — dataset edition and Kusilvak repair.
- US Census county-change notes — Wade Hampton renamed Kusilvak in 2015.
- ENERGY STAR dehumidifier guidance and rating changes.
- DOE water-heater fact sheet and A. O. Smith sizing guidance.
- DOE HVAC sizing strategy guide and ACCA Manual J.
What we do not claim.
We do not publish government-approved central HVAC coefficients, measured county groundwater temperatures, property-specific solar yields or guaranteed operating costs. Professional design and the manufacturer’s actual data can change any screen.
Report an outdated source through the contact page. Include the page URL and the supporting publication.