Research methodology

Which sources does HyreSolar use, in what order?

HyreSolar works down this list and stops at the highest tier that answers the question. Where no tier supports a claim, we publish the shorter page without it.

1. Federal agency data. EIA, DOE, IRS and the statute itself. First choice for anything quantitative or legal.
2. State agency rules. Energy offices, utility commissions, revenue departments and licensing boards.
3. Utility filings and tariffs. What a specific utility charges and pays, which can differ from the state-level summary.
4. Research institutions. National laboratories and academic work, where a question needs analysis we cannot do ourselves.
5. Manufacturer documentation. Datasheets and warranty documents, for equipment specifics.

We do not build figures from other content sites, marketplace quote data or installer marketing material.

Why does Form EIA-861 carry the analysis?

Form EIA-861 is a legal filing obligation for every electric utility operating in the United States. That makes it a census rather than a sample: no sampling error and no participating-company bias.

Form EIA-861 records residential sales, revenue and accounts; net-metered installations and capacity; batteries paired with them; metering and demand response; and reliability, utility by utility and year by year. We use the 11 annual releases from 2014 to 2024, downloaded as the published archives and extracted by script.

EIA does not publish the arithmetic between those columns: no official share of households with rooftop solar, battery attachment rate, consumption per account, or state ranking. Those are the figures we compute, across all 51 jurisdictions.

How is every figure labeled?

• Source data. A figure reported directly by the named source, unmodified. Example: EIA reports 5,077,543 residential net-metered installations in 2024.
• HyreSolar calculation. Arithmetic we performed on source data; EIA publishes the inputs, not this output. Example: installations divided by residential accounts.
• HyreSolar interpretation. What we think a figure means: an argument, not a measurement, labeled so you can disagree with it. Example: that adoption tracks retail price more closely than sunshine.

We never present our own calculation as an official statistic, or an interpretation as a measurement.

How was the derivation checked?

The check is external. Our residential price derivation (revenue divided by sales, per state per year) reproduces EIA’s own published state price series across 357 overlapping state-years to within 0.005¢/kWh. EIA rounds to two decimal places, so that difference is rounding.

Every consumption, bill and penetration figure we publish is built from the same quantities and inherits that validation.

Which dates does every figure carry?

• Retrieved date. When we took the data from the source. On every dataset.
• Data vintage. Which release the figures come from. Final releases only: mixing in partial early releases produces a break that looks like a finding.
• Last reviewed. When a person last checked the page, not when it was generated.
• Effective date. On anything time-sensitive, such as an incentive or a statutory change, with the source that establishes it.

What rules apply to cost figures?

A price is the figure most likely to be read as a promise, so cost figures carry stricter rules than the rest of the site. Each published cost cell (one price for one system type, size or region) must meet all of these:

1. At least 12 quotes per cell. A range or median is published only when it rests on twelve or more sourced, dated price observations for that exact cell. Fewer than twelve and the cell is left out, not estimated.
2. Every observation is sourced. Each one traces to a named source: a published dataset, a filed tariff or program report, or a dated written quote.
3. Every observation is dated. We record when each price was quoted or published and when we retrieved it. The page shows the retrieval date and the date range the cell covers.
4. No interpolation. A state or system-size figure is never derived by scaling a national average. If the local data does not exist, the page says so.
5. The n is shown. The number of observations behind a cell is published beside it, so a reader can weigh a range of 12 differently from a range of 300.

This standard applies to cost tables from October 2026. A cost figure that does not meet it is removed or flagged when its page is next reviewed, and substantive changes are recorded in the corrections log.

What limits apply to every figure?

• Net-metered systems only. Capacity under buyback, feed-in or utility-owned arrangements sits on a separate schedule and is excluded from installation counts.
• Accounts, not buildings. Penetration counts residential electricity accounts, which are not identical to households or dwellings.
• Means, not medians. The source has no median, so averages are pulled upward by a small number of large systems.
• Small populations swing. Where counts are low, ratios move on small absolute changes. Read the count alongside any rate.
• The data lags. By about two years. It describes a market that has moved since.
• A market is not your house. No figure we publish is an estimate for your property, tariff or tax position.

What happens when HyreSolar is wrong?

HyreSolar publishes figures so they can be checked. If you find an error, tell us the page and the number. We check it against the source and either correct it in place or explain why it stands. The editorial policy covers independence and corrections.

Can I cite or reuse this work?

Yes, with attribution to HyreSolar and a link to the page you took it from. The data downloads give the underlying tables as CSV, and the research hub lists every study.

What are the standing sources?

• US EIA, Form EIA-861 — Net Metering (annual files, 2014–2024): Utility-level net-metered capacity, installations and energy sold back by state and customer sector, plus PV-paired battery capacity and installations from 2023. Downloaded as the published annual ZIP archives. Retrieved 2 September 2026.
• US EIA, Form EIA-861 — Sales to Ultimate Customers (annual files, 2014–2024): Utility-level residential revenue, sales and customer counts by state, used to derive the average residential price and to count the households a state actually meters. Retrieved 2 September 2026.
• US EIA, Form EIA-861 — Distributed Generation that is not Net Metered (2024): Residential photovoltaic capacity served under buyback, feed-in and utility-owned arrangements rather than net metering. Capacity only; this schedule collects no installation count. Retrieved 2 September 2026.
• US EIA, Average Price of Electricity to Ultimate Customers by End-Use Sector: EIA’s own published state price series, used only to validate our derivation. Agreement across all 357 overlapping state-years is within 0.005¢/kWh, i.e. EIA’s own rounding. Retrieved 2 September 2026.