Home Systems Reference
Every US home runs on six major systems. This hub is your entry point to each — how it works, what commonly breaks, what's safely DIY, and where to call a licensed pro.
The 6 home systems, in depth
Every US home runs on the same six systems. This hub is the entry point to each — how it works, what commonly breaks, what's safely DIY, and where you should always call a licensed pro. Pages tagged high-risk are reviewed by a US-licensed contractor before publication.
Why we run system hubs separately from room hubs
A leaking toilet is a bathroom issue and a plumbing issue. A dead outlet is a kitchen issue and an electrical issue. Both are valid entry points — and homeowners search both ways.
Room hubs help you find fixes by location ("something's broken in my kitchen"). System hubs help you find fixes by discipline ("I need to understand how my breaker panel works"). Individual fix pages live once, at a canonical URL, and appear in both hubs so search engines don't see duplicate content.
The safety framing on every system page
Every system has a "when to call a pro" section that spells out the specific work you should not DIY. Electrical panel work, gas line work, structural modifications, multi-story roof work, and refrigerant work are all licensed-pro-only regardless of your experience — and every system hub says so up front.
For the full breakdown of what we teach and what we won't publish DIY instructions for, see the safety disclaimer.
Frequently asked questions
Electrical, by a wide margin. Even for DIY-safe electrical work (outlet swap, switch replacement, light fixture install), every page is reviewed by a licensed electrician. For panel work, gas-adjacent circuits, generator transfer switches, and EV chargers, we do not publish DIY instructions at all — those are always pro-hire.
Anything downstream of the gas meter and shutoff — gas water heaters, gas furnaces, gas ranges, gas dryers, gas fireplaces, and the flexible connectors between them. We publish shutoff procedures and evacuation protocols; the actual gas work is licensed-plumber territory.
Reviewed pages show a credit line directly below the byline: 'Reviewed by [Name], licensed [role] in [state]. Verified [date].' Reviewer bios are on the Contractor Reviewer Credentials page.