How we research balcony solar

What our labels mean

Every important fact on this site carries one of these labels, right next to the fact, with the source linked.

• ✓Verified We read the primary source (law text, regulator, or certification record).
• ◐Reported Supported by credible reporting; primary-source check in progress.
• •Maker's claim Stated by the manufacturer; certifier listing check in progress.
• –Pending Research in progress.

A label describes what we checked, not how good a product is. A product can be excellent and show Maker's claim while we confirm its certification record.

State laws

• We read the bill text on the state legislature's own website. A legal fact is only marked Verified when it appears in that text.
• News coverage (for example pv magazine USA or Canary Media) can earn a Reported label while we track down the primary text.
• Each state page shows the date we last checked it. That date only changes when we actually re-check.
• States without a page have no enacted plug-in solar law yet. That is not the same as a ban: it means the normal rules for connecting solar to the grid apply, which usually means your utility's interconnection process.

Products and certifications

• Specifications and prices come from the manufacturer's official U.S. store or spec sheet, with the date we saw them. Prices change; always check before buying.
• A certification (for example UL 1741 or UL 3700) is only marked Verified when we find the listing in the certifier's own directory (UL Product iQ, Intertek, CSA). Until then, a manufacturer's certification statement is shown as a Maker's claim.
• Product pages are profiles built from official specifications, store listings and certification records. When we test hardware hands-on, the page says how, for how long, and whether the sample was provided.

How the savings calculator works

Most balcony solar calculators multiply panel watts by sunshine by your electricity price. That overstates savings, because power you make while nobody is using it is often worth nothing: plug-in systems are usually not paid for power sent to the grid.

Ours walks through a full year, one hour at a time. For each hour it works out how much the panels produce at your state's location, how much of that your home uses right away, and how much flows out to the grid. You get money back only for the first part, unless you tell us your utility pays for exports.

• Sunshine: PVGIS 5.3 (European Commission Joint Research Centre), long-run average for your state's Census 2020 center of population, with 14% system losses.
• Hour-by-hour shape: one real weather year (2020) from PVGIS on your local clock (daylight saving included), scaled to the long-run yearly total.
• Shade: we cut output by 15% for "some shade" and 40% for "heavy shade". These are our rough figures, not measurements.
• Home use: 150 W running all the time (fridge, router, standby), plus 150 W or 350 W between 9am and 5pm if someone is home. Change these if you know your own numbers.
• Output above the inverter limit is lost (clipped).
• No battery, no price increases, no panel aging, no tax credits.
• Starting electricity rates are the U.S. Energy Information Administration's average residential price for your state, year to date. Your own bill is better if you have it.

The result is an estimate, not a promise. Try the calculator.

Safety

This is electrical equipment. We rely on UL, adopted electrical codes, fire services, utilities and official manufacturer instructions. We never suggest bypassing a code, defeating a protection device, using adapters or modifying certified equipment.