The Energy & DIY Tools Hub exists to answer one kind of question well: what will this actually cost me? Energy decisions — charging an EV at home, replacing a furnace, putting panels on a roof — are usually discussed in vague percentages and national averages. Every tool here instead asks for the few numbers that are specific to you, shows the formula it applies, and walks through the arithmetic in plain language underneath the result.
The tools
- EV Charging Cost— What a home charge actually costs, from battery size and your utility rate.
- Appliance Running Cost— Daily, monthly and yearly cost of running any appliance by its wattage.
- Solar Panel Payback— Break-even years on a solar array after tax credits are applied.
- Heat Pump Savings— Heat pump running cost against your current gas bill, and its payback period.
Fast, free, and private by design
Every page on this site is pre-rendered as plain static HTML and served from a global CDN, which is why the tools load close to instantly and work on a slow phone connection. There is no sign-up, no paywall and no usage limit.
The privacy part is a consequence of how the calculators are built rather than a promise we ask you to take on trust. The maths runs entirely in your own browser using JavaScript on the page. There is no server to send your inputs to: your bills, rates and system costs are typed into the page, calculated on your device, and discarded when you close the tab. We never see them and we could not store them if we wanted to. Our Privacy Policy covers the one genuine exception, which is the third-party advertising that keeps the site free.
How the site is funded
The tools are supported by advertising, which is why you will see a cookie notice on your first visit. We do not take sponsorship from installers, manufacturers or utilities, and no tool is tuned to make a particular product look good. Where the honest answer is unflattering — the heat pump calculator will happily tell you that a payback period runs to decades against cheap natural gas — the tool says so.
A word on accuracy
These calculators are estimating tools, not appraisals. They deliberately use transparent, straight-line maths and each one lists the assumptions it leaves out, so you can see exactly where a real-world figure might drift. For a purchase of any size, treat the result as a way to sanity-check a quote rather than as a substitute for one. Found a number that looks wrong? Please tell us — corrections are genuinely welcome.