About this site and its method
SolarPlug is a small independent reference about plug-in solar: kits of one to a few panels with a microinverter that connect to a home through a standard outlet. It is not a store, an installer or a law firm, and nothing here is legal advice.
Where the numbers come from
- State laws. Each state's status, bill number, dates and limits are read from the legislature's own bill pages: the text, the votes and the governor's action. The Bright Saver tracker is used as a second source; where it and the bill page differ, the state page says so. Every state shows the date it was checked.
- UK rules. SI 2026/848 on legislation.gov.uk, the government's response and product specification on gov.uk, and the ENA Type Test Register for kits.
- Production. PVGIS from the European Commission's Joint Research Centre. US: PVGIS 5.2 PVcalc, PVGIS-NSRDB, years 2005–2015; Alaska is outside that database and uses PVGIS-ERA5. UK: PVGIS 5.3 PVcalc, PVGIS-SARAH3, years 2005–2023. Monthly totals come for each three-digit ZIP area and each postcode area; the hour-by-hour shape of the year comes from one point per state or region. PVGIS © European Union, 2001–2026.
- Electricity rates. US: the average residential rate by state from the EIA Electric Power Monthly. UK: the Ofgem price cap unit rate (26.32p per kWh from October 1, 2026).
- Assumptions you can change. The power a home always uses: 164 W, the average always-on load in the NRDC study of 2015. System losses: 14%, the PVGIS default. Battery round trip when a spec sheet gives none: 90%, an assumption. Power sent to the grid earns nothing unless you enter a rate.
- Kits. Specs and list prices come from the official stores, with the date checked. A kit shows as UL 3700 listed only with a UL listing; a seller's own statement shows as a claim.
How the pages are written
Facts are collected first, each with the address of the page it came from and the date it was read. Drafts are then written with the help of an AI language model that is given only those facts and the calculator's output. A script checks every number on a page against the facts, checks wording and spelling, and keeps a page off the site until it passes.
Nobody here has tested the kits. There are no ratings, user reviews or customer stories on this site. Prices, laws and the register change every few weeks; the date next to each one says when it was checked.
How the site earns
Links to sellers go through addresses that start with /go/ on this site. Where a store has an affiliate agreement with this site, a purchase after such a click may earn a commission at no extra cost to you, and the button reads “Check price”. Without an agreement the button reads “Official site” and opens the maker's store.
On October 14, 2026, no store has such an agreement, so every seller button on the site reads “Official site”. An agreement never changes what a page says about a kit or whether a kit is shown.
Corrections and contact
If something on a page is out of date or wrong, write to hello@solarplug.homes with the page address.
If the link does not open your mail app, copy the address: hello@solarplug.homes.