Data / Installed cost

Installed cost

What a system costs installed, on both published bases: competitive quotes, and what buyers actually paid.

Records

11

measured in dollars per watt, before incentives

With their own source

11

every record links out

Carrying a caveat

0

nothing flagged here

Verified

2026-09-05

all on one date

What this decides

Gross price, net cost, payback and every 25-year figure.

usd_per_watt is the MODELLED value: 2026 marketplace quote averages from one source for every state. lbnl_2023 is the REFERENCE value: LBNL Tracking the Sun medians for systems installed in 2023 (2023 dollars). The two differ by roughly 60% by methodology: Tracking the Sun records prices as reported in permit and incentive data across all installers and equipment tiers; marketplace quotes are competitive bids. Decision 2026-09-05: model on the marketplace basis and SHOW BOTH everywhere (engine: result.altBasis; pages: two payback lines). Never mix the two inside usd_per_watt; never interpolate a missing reference value.

Every record

Source column links the page or endpoint the value was read from. Where a row has no link of its own, it inherits the file-level source.

ONE source for every modelled state value: EnergySage Marketplace state pages, read 2026-09-05 (pages dated 2026-08-28). Each record carries its own source and verified_on. Never mix sources inside usd_per_watt: a ranking built on two sources ranks the sources. lbnl_2023 is reference-only and carries its own source.

Take it

• installed-cost.json

  The file the engine actually reads, unaltered, with the documentation blocks it carries.

• installed-cost.csv

  The 11 records flattened for a spreadsheet: value, verified date, source, caveats, note.

Our compilation is free to reuse with a link back. The underlying data is not ours to license — follow the source on any row for the authoritative version and its own terms. The full position.

The rest of the data

• Electricity prices

  What a residential kilowatt-hour costs, by state. The single biggest driver of whether solar pays.

• Solar yield

  How much electricity a kilowatt of panels makes in a year, by place. The only pure physics on the site.

• Export rules

  What the utility pays for a kilowatt-hour you send out. Decides payback more than sunshine does.

• State incentives

  What a buyer can actually claim from a state, read from the statute or programme that grants it.

• Federal policy

  The federal credit as data, versioned by year, with the dated events that changed it.

• Modelling assumptions

  Everything the model assumes rather than sources: panel wattage, degradation, loan terms, escalation.

Published 6 September 2026. Last verified 5 September 2026. A figure here that looks wrong is the mail we most want: tell us, and we publish corrections. The formulas that consume these records are on the methodology page.