Terms of Use

This is a free, public information site. There is nothing to sign up for and nothing to buy. Everything on it is a modelled estimate built from published data, not advice about your house and not a quote. Use it to get oriented and to check what someone else has told you; do not use it as the last step before signing something.

Last updated 6 September 2026. Questions: hello@straightwatt.com. See also the privacy policy and the cookies policy.

What this site is

StraightWatt publishes the economics of rooftop solar in the United States: what a system costs, what it saves and how long it takes to repay itself, computed by one published engine from data we read from primary sources and record with the date we read it. The calculator runs in your browser on the same code. There are no accounts, no payments, no comments and no user submissions, so most of what a terms page usually covers does not exist here.

By using the site you accept what follows. If you do not, the remedy is simple: do not use it.

These are estimates, not advice

This is the term that matters, and it is the reason it comes first rather than last.

Not financial, tax or legal advice: A tax credit figure here is a model of a published rule, not a determination of what you personally can claim. Whether a credit reaches you depends on your own tax position, which we do not know and do not ask for. Talk to a professional before filing anything.
Not an engineering assessment: We model a well-oriented, unshaded roof. We cannot see your roof. Shade, orientation, pitch, structural condition, the age of your covering and your electrical panel all change the answer, and only a site survey settles them.
Not a quote: Installed prices here are state averages. The spread between three real quotes for one roof is routinely wider than the spread between states on our own tables. Get quotes.
Not a prediction: Any figure covering more than a year rests on assumptions about the future, above all how fast electricity prices rise. That assumption is a slider in the calculator precisely because nobody knows it. Every formula and assumption is published so you can disagree with ours.

What we promise about accuracy, and what we do not

We promise the working. Every figure carries the source it came from and the date it was read; the whole evidence base is browsable and downloadable at the data index; the formulas are on the methodology page; and when we get something wrong we publish a correction rather than editing it away.

We do not promise the answer. The site is provided as it is, without any warranty that it is accurate, complete, or current. Sources go out of date, tariffs change without notice, and we make mistakes — three are already in the corrections log. A record was true on the date printed beside it and no later. If a figure here matters to a decision you are making, follow its source link and check it, which is why the link is there.

Availability is on the same footing: the site is static files on a shared host and may be unavailable at any time. Nothing here is guaranteed to keep working, though URLs we publish as permanent — the dated editions of the Solar Economics Index above all — are intended to stay put.

Using what is here

You may quote, republish and build on our work, including commercially, with a link back to the page you took it from. That covers the figures we compute, the tables, the charts, the per-state sentences in the index, and the compilation itself: which records we chose, the values we read, the source URLs and the dates.

Two limits, and neither is a lawyer's flourish:

The underlying data is not ours to give you: We do not own a government electricity series, a national laboratory report, a utility tariff or a marketplace's price average, and we cannot license to you what is not ours. Every record names its source; that source's own terms apply, and following the link is always the more authoritative move.
Take the sources with the numbers: If you republish a figure from this site, carry its source and its date, or link to the page that does. A number stripped of where it came from is exactly the thing this site exists to argue against, and we would rather you did not use ours to make one.

What we ask you not to do

Do not present our figures as your own original research, or imply that we endorse, checked or approved your use of them.
Do not use the site to generate sales leads, or represent yourself as connected to us to a customer.
Do not hammer the site with automated requests. Everything is static and the whole dataset is a download away; take the file instead.
Do not alter a figure and keep our name on it. Recompute it, say you did, and publish your inputs.

We do not sell solar

We are not an installer, a broker, a lead generator or a finance provider, and we are not affiliated with any of them. Nobody pays for a ranking, a mention or a favourable figure, and no company has been given the chance to review a number before it was published. If that ever changes, it will be disclosed on the page where it applies and not only in a policy nobody reads.

Links to other sites

This site links out constantly, because a source you cannot follow is not a source. Those pages belong to other organisations: their content, their availability and their terms are theirs, not ours, and a link is not an endorsement of anything beyond the specific fact we cited.

Advertising and affiliate links

There are none today. If the site ever carries advertising, the network will be named on the privacy policy and the cookies policy in the same release that introduces it, because an ad network is a third party that sets its own cookies and sees which pages you visit here.

If a link ever pays us, it will say so where it appears, not only here. What will not change is a number: the engine takes its inputs from published data, and no figure will be adjusted because one outcome pays better than another. If that is ever untrue, the corrections log is where it will be admitted.

Liability

Decisions about your own money are yours. To the fullest extent the law allows, we are not liable for any loss arising from a decision you make using this site — a system that does not pay back as modelled, a credit you turn out not to qualify for, a quote that comes in above our state average, or a figure that was wrong. Nothing here excludes liability that cannot lawfully be excluded.

Written plainly on purpose. It is a statement of how this site should be used, not a document drafted by a lawyer, and it is not a substitute for one.

Changes to these terms

This page is versioned with the site, so its history is the record of what changed and when. Material changes — advertising, affiliate links, anything that takes a payment or collects more than a message — will be dated here before or as they take effect, not quietly afterwards. Continuing to use the site after a change means accepting it.

Contact

A person reads the mail. hello@straightwatt.com, or the contact form. If you think a figure is wrong, that is the message we most want, and a complaint about anything on this page should start there rather than anywhere more formal.