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 or rent personal information, and we hold none to sell.

Advertising is the part that is not nothing, so it gets its own section below. Outside the EEA and the UK, the ad network receives your IP address and browser details in the ordinary way and may set cookies, which some US state privacy laws count as “sharing” even though no money changes hands over your data. Inside them, it starts switched off.

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

Two Google scripts run on this site: Google Analytics 4, which counts page views so we can tell whether anyone is reading this, and Google AdSense, which places the advertising that pays for it. Both can set cookies. Analytics records the page you are on, the page you arrived from, and coarse technical details like country, browser and screen size. It is not used to identify you by name, and we never upload anything to it that could.

Where you are changes what is stored. If you are reading this from the European Economic Area, the United Kingdom or Switzerland, Google's scripts start in a refused state: no analytics cookie, no advertising cookie, no advertising identifier. Your visit still registers as an anonymous count with no way back to you, and the ads you see are chosen from the page rather than from anything about you. We do this instead of showing a consent banner, because a banner that most readers dismiss without reading is a worse deal for them than simply not collecting the data.

Everywhere else, including the United States, the cookies are set in the ordinary way. You can refuse them in your browser settings, and Google publishes its own controls at My Ad Center and the Analytics opt-out. Blocking these scripts costs you nothing on this site: no feature here depends on them.

The calculators are not part of this. Everything you type into them is computed in your browser and never sent anywhere, to Google or to us. That is a property of how they are built, not a promise about how we behave, and the network inspector will confirm it.

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.

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.