Terms of Use
The calculators give estimates. They are not a design, a permit, or professional advice.
The tools are estimates
Each page states its formula, defaults, and sources. Results depend on the numbers you enter and on those disclosed assumptions (efficiency, depth of discharge, NEC table columns, EIA averages). Real hardware, temperature, wire length, and utility tariffs differ. Do not size a service, an overcurrent device, or a dwelling backup panel from this site alone.
Not professional advice
Nothing here is electrical, engineering, or legal advice, and nothing here replaces the National Electrical Code, a listed product's instructions, or a licensed electrician. Wire-size and inverter pages cite NEC rules as the basis for an estimate; they do not certify a compliant installation.
As-is, limited liability
The site is provided as is. To the extent the law allows, JouleCalc is not liable for decisions, purchases, or installations made from these estimates, or for downtime, ranking changes, or third-party sites we link to.
Outbound links
Source links (DOE, EIA, manufacturer spec sheets) and any future product links leave this site. Their content and privacy practices are theirs. Product ranking on this site, when a match list appears, follows the published smallest-capable-first rule — not a paid slot.