It is a lot of money, the advice is confusing, and almost everyone offering an opinion is also trying to sell you something.
This site is here to help you work it out for your own house, with calculators that show what they did. There is nothing to sign up to and nothing for sale.
Somebody still weighing it up wants different things from somebody about to sign, and both want different things from the person doing the work. Pick whichever sounds like you.
Give these your postcode and roughly what you spend on energy, and they will tell you the size of system that would suit your home, what it would generate or save, and how that compares with a quotation you have been given.
Works out the array a home needs — capacity, panels, battery and what it saves — from a postcode, a roof direction and a year of electricity use.
Work it outEstimates a house's heat loss and the heat pump that covers it, from a year of gas or oil bills, and says whether a quoted size looks plausible.
Work it outThere are nine more for checking a single figure on a quotation, such as the shading on a roof or the noise a heat pump makes at a neighbour's window.
Nothing here assumes you know the vocabulary. These take about five minutes each and make everything else on the site readable.
Energy prices only go up, the argument runs, so panels and a heat pump protect you against inflation. This article checks that against what electricity, gas and savings accounts did from 2016 to 2025, for one solar roof and one heat pump.
Panels, inverters, heat pumps, batteries and cylinders all have different lifespans. Knowing which is which stops a normal replacement feeling like a failure.
Three numbers on your bill do all the work, and finding them takes about five minutes. They are also the numbers every calculator here asks for.
Longer pieces on whether each of these suits a house like yours.
What changes in a house that gets a heat pump, the conditions it needs to work well, and how to tell early on whether yours is a good candidate.
The things worth doing before you spend anything, because each one makes the machine you end up buying smaller, cheaper, or better matched to the house. Most of them cost nothing.
The grant that pays part of the cost of replacing a boiler with a heat pump in England and Wales. What it is worth, who can have it, and what the April 2026 rule changes opened up.
What a roof will realistically generate, why the direction matters less than you think, and why the same panels are worth more to some households than others.
Less needs doing than for a heat pump, and one thing people expect to have to do turns out not to matter at all. What is worth checking before you get anyone out.
The vocabulary, the units and the bills. The things everything else on the site assumes you already know.
How they work, how they are sized, and what makes one cheap or expensive to run.
What a roof will generate, how that figure is arrived at, and what happens to the electricity.
What storage does for a house that already generates.
What an MCS certificate says about an installer, and the standards it is based on.
Planning, building control, the network operator, and the documents an installation should leave behind.
