Every figure in our homeowner guides traces back to the organization that publishes it. This page shows how that works: what counts as a source, how we check a figure, how we keep it current, how we make money, and what happens when we get something wrong.
How does The Day Company check the figures in its guides? Every figure in our homeowner guides comes from a dated public source — usually Illinois law, the utility’s own tariff or a state program document — or we don’t publish it. We date every figure, re-check it when its source changes, label our own math as illustration, and record every correction in that page’s changelog. Homeowners never pay us, and what our partners pay us never changes a number.
From the organization that actually publishes them — the law, the regulator, the utility or the program. If we can’t trace a figure to a source like that and date it, it doesn’t go in a guide. These standards cover everything we publish for homeowners: the home page, our Illinois solar guides and the answers library.
| Kind of source | Who | What we use it for |
|---|---|---|
| Illinois law and regulators Primary | Illinois General Assembly (ilga.gov), Illinois Commerce Commission, and Plug In Illinois, the ICC’s price-to-compare site | Statutes, approved tariffs, program rules and utility supply prices |
| State programs and agencies Primary | Illinois Power Agency and Illinois Shines, Illinois Department of Revenue | REC prices, program guidebooks and disclosure forms, and the property-tax filing (PTAX-330) |
| Utilities and grid operators Primary | ComEd, Ameren Illinois, PJM and MISO | Rate schedules and tariffs, rebate terms, net-metering rules and capacity-auction results |
| Federal agencies, national labs and local government Primary | IRS, U.S. Energy Information Administration, Lawrence Berkeley National Laboratory, and city building departments | Federal credit rules, household usage data, national installation data, and local permit rules and fees |
| Consumer advocate Secondary | Citizens Utility Board (CUB) | Bill analysis and plain-language rate explanations — always named as the source |
| Not a source Not used | Marketplaces, lead aggregators, installer and manufacturer marketing, and uncited articles | We may link to them for context. We never cite them for a figure. |
Every guide lists its own sources at the bottom of the page.
We rank sources by how binding they are. When two disagree, we report both, name the gap, and say which one controls your situation today.
The order we follow, most binding first:
Two conflicts our guides report right now. First, Illinois law makes an hourly or time-of-use rate optional for a rebated battery, but ComEd’s 2026 rebate terms still require a qualifying rate for the life of the battery. Our battery guide reports both and says which one governs a ComEd application today. Second, Ameren’s customer solar page lists its battery-rebate requirements but leaves out the virtual power plant enrollment its own tariff and bulletin require. We say so, and tell you to confirm it in writing.
Every figure gets the same checks. Some kinds of figures never run at all.
Every guide shows when it was last reviewed, and figures carry the date they took effect or the date we read the source. Those dates differ on purpose: a page reviewed today can still show a rate that took effect months ago.
A guide’s “Last reviewed” date moves only when its figures were actually re-checked at their sources. Fixing a typo or adding a link doesn’t move it.
These events trigger a re-check of the figures they touch:
A few labels show up across our guides. Here’s what each one means.
Homeowners never pay us, at any step. We may be paid by installation partners when we connect them with qualifying homeowners who ask to be contacted.
That’s the whole model, and it’s why our free eligibility check exists. When solar isn’t a fit for a home, the check says so.
When a guide names a company, it’s because that company’s own offer is the subject, like the two battery-subscription contracts we compare. We link the company’s own documents.
The Day Company Editorial Team. We publish as a team, at the organization level, rather than under individual bylines.
Every guide is researched against the sources above and checked before it goes live. Each one names the team as its author and shows when it was last reviewed. To reach the team, email [email protected].
Email us with the subject line “Correction.” Include the page, the figure you think is wrong, and a link to a primary source that contradicts it.
We check the source. If it confirms the error, we fix the page and record the fix in that page’s changelog. If the source supports what we published, we reply with the citation.
A problem with a solar company rather than a page? Our corrections page lists the official channels for that.The Day Company Editorial Team. We publish as a team, at the organization level. Every guide is checked against primary sources — Illinois law, the utilities’ own tariffs, state program documents and federal agencies — before it goes live.
Homeowners never pay us. We may be paid by installation partners when we connect them with qualifying homeowners who ask to be contacted. What we’re paid never changes a figure in our guides.
No. No company pays to be mentioned, ranked or recommended in our guides, and no partner reviews or edits a guide before it’s published. When a guide names a company, it’s because that company’s own offer is the subject, and we link the company’s own documents.
Whenever something that could change them happens: a utility supply-price reset (June 1 and October 1), a new or changed tariff, a new Illinois Shines program year, a capacity-auction result, new federal guidance or a court ruling, or a new Illinois law. A guide’s “Last reviewed” date only moves when its figures were actually re-checked at the source.
No. The Day Company is an independent company. We’re not a utility, a government agency, Illinois Shines, the Citizens Utility Board or the Illinois Commerce Commission, and we don’t represent any of them. Utility names on our pages identify service territories only.
Email us with the subject line “Correction” and include the page, the figure you think is wrong, and a link to a primary source that contradicts it. The address is on our corrections page and at the foot of every page. If the source confirms the error, we fix the page and record the fix in that page’s changelog.
Who we are, how we’re structured, and how we make money.
Read about us → CorrectionsHow to report an error, and what happens when one is verified.
See the policy → The answers libraryOne sourced guide per homeowner question, with every figure dated.
Browse the library → Illinois Solar FactsThe dated figures behind our guides, for both utilities, in one place.
See the data →How to cite this page: The Day Company Editorial Team, “How we source, verify, and correct every figure,” The Day Company, updated September 29, 2026. https://theday.company/editorial-standards
The free eligibility check takes about a minute. There’s no obligation, and if solar isn’t a fit for your home, it says so.
The Day Company is an Illinois solar and battery information resource and a lead-generation business. Information you submit may be used by our review team and authorized partners to contact you about your request. Checking eligibility creates no obligation.