Getting the house warm and cheaper to run this winter

Heating is the biggest part of most UK energy bills, so the order of the work matters: stop the heat escaping first, then make sure the radiators and boiler suit the house, then look at what everything costs to run. Insulation done first can even let you fit a smaller boiler or heat pump later.

This planner follows that order. It covers planning and quantities only: gas and electrical work must be done by a registered gas engineer or electrician.

Step 1: Insulate the loft

Loft insulation is usually the cheapest and quickest saving. About 270 mm of mineral wool is the usual recommendation for a cold loft. Work out the rolls from the depth you already have, and keep the eaves clear so that the roof can breathe.

Step 2: Lag the pipes

Pipes and tanks in the loft, the garage and under the floor need lagging before the first hard frost. Measure the length of pipe and choose foam to fit its diameter, and use tape or ties to close the joints.

Step 3: Check the radiators and the boiler

A room needs a radiator whose output matches the heat it loses, and rooms with several outside walls or single glazing need more. The boiler is sized from the heat loss of the whole house and, for a combi, the hot water used at once. A heat pump has its own sizing rules and needs larger radiators, because it runs at a lower flow temperature.

Step 4: Add a wood burner or underfloor heating

A stove is sized from the volume of the room, and an oversized one overheats it. Electric underfloor heating is sized from the floor area, and its running cost depends on how long it is on and your tariff.

Step 5: Work out what it all costs to run

The cost of an appliance is its kilowatts, times the hours it runs, times your price per kilowatt-hour. Heaters and tumble dryers cost the most. A plug-in energy monitor shows you exactly what each appliance uses, and solar panels can supply some of the power.

Before you start

• The depth of loft insulation you already have, measured in millimetres.
• Pipes and tanks in cold spaces lagged.
• Radiators bled and, if any are cold at the top, a boiler pressure check.
• Your current tariff and meter readings, to work out running costs.
• A registered gas engineer for any boiler or gas appliance work.

Mistakes that cost people money

• Blocking the eaves ventilation with loft insulation.
• Covering recessed lights or flues with insulation.
• Buying a bigger boiler before fixing the heat loss.
• Fitting a wood burner that is too big for the room.
• Leaving the pipes in the loft unlagged until the first frost.

Frequently asked questions