The data behind every number on Solarly.
We cite our sources. Here’s where the numbers come from — plus the tools, standards documents, and community resources we find most useful for anyone going deeper on plug-in solar.
Our own state-by-state population analysis, methodology included.
The law, state by state, plus a playbook for getting approved.
What to know before you plug in — a gap nobody else in the space has covered.
Our own tool. Enter your address — get a real aerial snapshot, sun exposure, legality check, and kit picks for your exact setup. Free, no email required.
The gold standard for solar production estimates. Enter any address, panel size, and tilt angle — get precise kWh output by month. Used by installers and researchers.
Where we get US electricity rates. The US Energy Information Administration publishes average retail rates by state every month. The authoritative source for savings math.
National Renewable Energy Laboratory’s complete solar research library. Efficiency records, system performance data, cost benchmarks. Peer-reviewed, free to access.
A newer US safety standard written specifically for plug-in solar systems, covering automatic anti-islanding shutoff, overload protection, and weatherproofing. It launched in early 2026 — no products have completed certification under it yet, so our current kit picks meet the established UL 1741 standard instead.
📌 What to look for: Right now, every kit we link to on Solarly meets UL 1741 — the established standard for grid-connected inverters. UL 3700 is newer and written specifically for plug-in solar, but no products have completed certification under it yet; we’ll update our picks as that changes. If you’re in Canada, check that the kit is also CSA or cUL listed, which indicates it’s been tested to Canadian electrical standards.
The original Greener Homes Grant closed to new applicants in 2024. It’s been succeeded by this income-qualified program, which arranges free, direct-installed energy upgrades (including solar, where eligible) rather than a self-serve rebate — check eligibility before assuming it applies to you.
Canada’s national solar industry association. Good source for provincial policy news, industry statistics, and regulatory updates affecting DIY and plug-in solar.
📌 Note for Canadian readers: Solarly’s primary focus and all savings and legal data are US-specific — this section is a supplementary reference for Canadian readers, not a core coverage area. Plug-in solar regulations in Canada vary by province and are still evolving. British Columbia and Ontario are the most permissive. Québec’s low electricity rates make the math less compelling but the technology still works. We’re building out province-by-province coverage — check back in the coming months.
Germany has registered over 1.3 million plug-in solar units (Balkonkraftwerke). This is the largest single dataset of real-world plug-in solar deployment anywhere. North America is 3–5 years behind.
The largest English-language community for plug-in and DIY solar. 200k+ members troubleshooting setups, sharing installs, and comparing kits. The wiki is excellent for beginners.
Every savings estimate on Solarly is derived from publicly available data: electricity rates from the EIA, solar output from NREL’s PVWatts, and panel specifications from manufacturer datasheets. We don’t use installer-provided estimates or marketing figures. Payback periods use street prices for kits, not sale prices. We update rates when the EIA releases new monthly data.
When we get something wrong, we correct it with a visible strikethrough and note the date of correction. If you find an error — in a number, a law summary, or a kit spec — email us. We take corrections seriously.
We do not accept advertising from solar installers, kit manufacturers, utilities, or any entity with a financial interest in our recommendations. The kit picks are editorially independent.
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