Shorter pieces on one question at a time, from the basics up: what changed in the rules, what a new technology is worth, and what a particular figure on a quotation means.
From 27 August 2026 you can plug a small solar panel straight into a socket. What that changes, what it does not, and whether it is worth doing.
6 min read
9 articles
No background assumed. Start here if the vocabulary is new.
No standard, grant or network rule requires one, and a heat pump will run without it. What a smart meter changes is which electricity tariff you can be on, and on a heat pump the tariff decides a large part of the running cost.
Panels get a little better every year, which makes waiting sound sensible. What a year's delay costs, worked through with real numbers.
A house with solar panels and a battery usually goes dark in a power cut like everybody else. It is not a fault, and it is fixable, but only if you ask before it is installed.
Panels, inverters, heat pumps, batteries and cylinders all have different lifespans. Knowing which is which stops a normal replacement feeling like a failure.
It is meant to. A heat pump that ticks over all day costs less than one switched on and off, and the radiators are supposed to feel lukewarm. Here is why, and what that means for how you use it.
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.
Bills, quotations and savings on this site are all counted in kilowatt-hours. What one is, and how to find out how many your house gets through.
The paperwork is not a formality. The certificate, the design calculations and the commissioning records are what prove the installation was done to the standard, and they are needed years later.
MCS publishes a short document setting out what a certified contractor undertakes to do for its customers. It is worth reading before signing anything, because it describes what you are entitled to expect.
9 articles
Assumes you know roughly how the technology works and what a bill looks like.
Once the panels are on the roof the generation is fixed, and what the system is worth depends on what the house does with it. This covers the habits, settings and annual checks that keep a solar system paying, and the signs that something has gone wrong.
A heat pump is set up once, on commissioning day, for a house the installer had known for a few hours. The settings that decide the running cost can be improved through the first winter and checked every year after. This covers the settings worth revisiting and the checks worth making each year.
A heat pump cannot make hot water on demand, so a house that has lived without a cylinder gets one back. How it is sized follows a formula in MIS 3005-D and a table in MGD 007.
A heat pump quoted at 4.5 and one quoted at 3.1 may be the same machine measured differently. What each figure means, and which of them to compare quotations on.
A shadow across one corner of an array can cost far more than its share of the roof. MGD 005 gives a standard way of measuring the loss, and it is the term in a solar estimate most often left at zero.
Anything that generates or stores electricity has to be notified to the local network operator, and above a certain size has to be approved before it is connected. The difference is worth knowing before signing.
The MCS method is fixed, so two correct estimates for the same roof should agree. When they do not, the difference is nearly always in one of five inputs.
Both collect heat from outside the house instead of making it. The difference is where they collect it from, and that one difference sets the cost, the efficiency and the disruption.
The MCS standards fix the method behind the numbers, so a quotation that follows them has certain things in it. What to look for, and what it usually means when one of them is missing.
3 articles
Methods, edge cases and the detail behind a figure. Assumes the intermediate pieces.
Most air source heat pumps are installed under permitted development, and one of the conditions is a noise calculation. This is what the calculation does and what fails it.
The anode chemistry that let phone makers pack more capacity into the same case is being talked about for home storage. What it gives up in return, and why that matters in a battery meant to last fifteen years.
A heat pump quotation should come with a room-by-room heat loss calculation. Here is what its columns mean and the handful of checks that catch most errors.