Cut your energy bills without living in a jumper

Why the order matters

A typical UK home leaks money in layers. Some goes through habits, some through the boiler’s factory settings, a surprising amount through the loft, and the rest through the plain fact that gas and electricity cost what they cost. Attack the layers in the right order, because each fix changes the maths of the next one.

Insulate before you size a heat pump and the pump can be smaller and cheaper. Measure before you insulate and you will know what actually worked. Do it backwards, buying generation before stopping waste, and you spend thousands producing energy the house then throws away.

Step one: measure

Start with a smart meter. It is free from your supplier and should never cost you a penny, whatever a cold caller says. The in-home display turns kilowatt-hours into pounds while you watch, which is the thing that actually changes behaviour. Our smart meter guide covers what they do, what they do not, and how to revive one that has gone quiet.

Then give it one ordinary week. Note what the house burns on a day when nobody does anything unusual. That number is your baseline, and every fix below either moves it or gets crossed off the list.

Step two: stop the waste that costs nothing

The cheapest kilowatt-hour is the one you never buy. First, turn down your combi boiler’s flow temperature, the temperature of the water sent to the radiators. Most leave the factory set in the 70s; nearer 60°C the boiler condenses properly and burns less gas for the same warm house. It is a dial or a menu setting, it is reversible, and it is free.

Second, the schedule. Heat the hours you live, not the hours you sleep, and make each degree earn its place; our guide to thermostat settings that save money has the details, TRVs included. Third, draughts. A windy afternoon, the back of your hand, and a £20 roll of draught strip will find and fix the worst offenders in a weekend.

Step three: insulate, loft first

Heat rises, and in an under-insulated house it keeps going. Topping the loft up to 270mm is the rare home improvement that can pay for itself within a couple of winters, and a careful DIYer can do it in an afternoon. Start with insulation, in the right order: loft, then draughty floors, then walls, each with its own honest price tag.

One caveat that rarely gets airtime: insulation without ventilation grows mould. Keep trickle vents open and extractor fans working as you seal the house up. Warmer and damper is not the goal.

Step four: generate

With waste down, generation starts to make sense. A 4kW array costs £5,000–£8,000 installed at the time of writing, and the honest maths on solar puts payback at years, not miracles. East-west roofs work fine, whatever the doorstep salesman sighs about. The Smart Export Guarantee pays you for exported units, though using your own generation is where the real value sits.

Step five: electrify the big loads

Heating is the heaviest load in a UK home, which is why the heat pump readiness question comes after insulation, not before. A well-designed pump in a prepared house is quiet, cheap to run and slightly boring. The same pump in a leaky house is an expensive way to feel lukewarm. And yes, they work in a British winter; the steam clouds are part of the plan.

At the time of writing, the Boiler Upgrade Scheme offers £7,500 towards an air source heat pump and energy-saving materials carry 0% VAT. If you drive, a home EV charger at £800–£1,200 installed, paired with an off-peak tariff, makes miles cheaper than any forecourt has managed in living memory.

When to do what

Energy work has seasons. Summer is for quotes and installs while trades are quieter; autumn is for the free settings and the loft; winter is for watching the meter prove it all worked.

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The paperwork bonus

Every measure above nudges your EPC, which matters when you sell, let or remortgage. The scoring has quirks, it models running costs rather than comfort or carbon, so read up on improving your EPC rating before spending with points in mind. Some cheap wins score generously; some expensive ones barely register.