Privacy Policy

The short version

We do not ask for your name, email address, phone number or street address, and there is nowhere on this site to give them to us. The calculator runs entirely inside your browser: the figures you type never leave your device and never reach our server. We do not sell, rent or share personal information, because we do not hold any.

What the calculator does with your inputs

Your electricity bill, system size and cost assumptions are processed by JavaScript running on your own machine. There is no form submission, no API call and no logging of what you enter. Closing the tab discards it. You can verify this yourself: open your browser's network inspector and use the calculator — you will see no outbound requests carrying your figures.

State sunlight and electricity-rate data is compiled when the site is built and shipped as a static file. Your browser reads it locally rather than querying anything about your location.

Server logs

Our web server keeps standard access logs — IP address, timestamp, page requested, browser user-agent — as essentially every web server does. These are used to keep the site running and to detect abuse. They are not combined with anything else, not used to build a profile of you, and not given to third parties except where we are legally compelled.

Cookies and analytics

This site sets no cookies. Not for analytics, not for preferences, not for anything.

There is one third-party script: Cloudflare Web Analytics, loaded from static.cloudflareinsights.com. It counts page views so we can tell whether anyone is reading this. It records the page, the referrer, coarse technical details like country and browser, and page speed measurements. Your IP address reaches Cloudflare as part of any web request, but it is not used to identify you or to link your visits together.

It sets no cookie and uses no other client-side storage, and Cloudflare states it does not fingerprint visitors by IP, user agent or any other technique — their stated position is that fingerprinting is worse than cookies, because you cannot opt out of it. That is why we use this rather than Google Analytics.

Cloudflare also sits in front of this site as a CDN, so your request reaches their servers before ours. Their network may set a security cookie to distinguish real visitors from automated traffic. That is Cloudflare's processing under their own policy, not ours.

There is no advertising script on any page today. That will change when the site carries ads, and when it does an advertising network will set cookies or similar identifiers — this page will be updated in the same change that adds them, naming the provider and how to opt out. Until you read that here, the paragraphs above are the whole story, and the network inspector will confirm it.

Links to other companies

Some outbound links are affiliate links, meaning we may be paid if you go on to do business with the company. This is disclosed at each link and explained on our disclosure page. Following one takes you to a site with its own privacy policy and its own data practices, over which we have no control. If a company asks for your phone number, that relationship — and the consent to call you — is between you and them. We are not a party to it and we never receive your details.

What we deliberately do not do

• We do not collect phone numbers. There is no field for one anywhere.
• We do not generate or sell sales leads. We are not a lead generator or a data broker, and the site is built so that we cannot become one by accident.
• We do not email you, because we have no way to.
• We do not fingerprint devices or use session replay.

Your rights

Privacy laws including the California Consumer Privacy Act give you rights to access, delete and opt out of the sale of your personal information. We hold no personal information about you beyond the server logs described above, so in practice there is nothing to retrieve or delete. If you believe otherwise, or want to ask about the logs, write to us at the address on our about page and we will respond within 45 days.

Children

This site is aimed at homeowners making a purchasing decision. It is not directed at children and we knowingly collect nothing from anyone.

Changes

Material changes will be reflected in the date at the top of this page. Because the promises here are enforced by how the site is built rather than by policy alone, a change to the policy means a change to the code.