Observed arrival · 2026-10-14
How House Works turns appliance codes into a cited reference
A reference for U.S. home-equipment error codes, with calculators for generator sizing, water-heater demand, and heat-pump costs.
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- For
- U.S. homeowners checking equipment codes or sizing
- Worth noticing
- Its listed coverage includes 116 Rheem codes and 99 MrCool codes; the site says code pages that fail its source check are withheld until fixed.
Field notes
The homepage organizes code lookups by equipment type and manufacturer, with example links for Rinnai and Navien codes. Its stated checking process compares claims with cited manufacturer documents and holds back pages that fail, but the site also discloses that drafts and checks use AI tools and that no licensed tradesperson has reviewed the pages. The extract does not include the individual entries or calculator workings.
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