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Last updated: 18/07/2023 | Estimated Reading Time: 6 minutes

Top tips to keep your house energy efficient

The per unit prices of gas and electricity have risen recently. Wholesale prices has ticked upward, and suppliers have faced higher network costs for transporting energy and costs associated with social and environmental schemes required by the government. As a result, it's more important than ever to make sure you're paying as little as possible for you energy supply. You can compare gas and electricity tariffs with us to find a great deal, but no matter how much you're paying per unit, there are always things you can do around the house to keep costs as low as possible.

In This Guide:

Avoid rising energy prices

Ofgem has recently raised the ceiling on its price cap on default and standard variable tariffs by £117 to reflect these inflated costs, adding significantly to the bills of 11 million British households.

Many of these consumers will be looking to cut costs, to offset high energy prices and reduce household expenses, especially as wages have stagnated and disposable incomes dipped.

Comparing energy tariffs remains the best way to trim your energy bills, with more than £200 in yearly savings available to savvy shoppers. But you can also notch significant savings by increasing the energy efficiency of your home, insuring you're not throwing away pounds by heating air that seeps directly out thin walls and up your unblocked chimney.

And there are other motivations for making your home into an energy efficient machine: you can reduce your personal carbon footprint, and your own contribution to climate change. And most of these changes will pay dividends if you ever sell the property, as potential buyers, especially those of the future, will look for homes that won't cost them much to run and that won't need to be modified to meet any future efficiency requirements.

The heating of rooms accounts for two-thirds of the energy diet of the typical British home, and half of its energy costs. Additionally, the heating of our buildings, both domestic and commercial, is responsible for 20% of the UK's greenhouse gas emissions. So when increasing the energy efficiency of your house, it makes sense to start with its heating.

Insulate your loft and roof

In homes that aren't properly insulated, 25% of the heat produced by your boiler will escape through the roof. In fact, the government has estimated that Britons are collectively wasting £500 million a year heating air that leaks straight through their roofs and walls. You can stem much of this loss by investing in loft insulation or by improving your existing insulation if it isn't up to par (look for at least a 270 mm thickness). Professional loft insulation can cost more than £400 but home improvement hobbyists can DIY it for significant savings. Which? reports that you can save up to £225 on your energy bills each year with loft insulation, and also keep 990kg of CO2 out of the atmosphere.

If you're using your loft for living space, you'll have to look into roof insulation, which can be pricier and more difficult to install, but delivers much of the same benefits.

Insulate your walls

40% of the heat lost from your home will be through the walls. If you have cavity walls (walls with two layer of brick and a gap between them, to prevent damp), insulating them can pay for itself within five years, according to the Energy Savings Trust. The Trust ran the numbers, to show you how much money you can knock off your energy bills-and how much carbon dioxide you can keep from the atmosphere-depending on the size of your home.

Savings from cavity wall insulation

Type of property

Installation costs

Savings per year

Time to pay off

Carbon savings per year

Mid-floor flat



<5 years

310 kg CO2

Mid-terrace house



<4 years

410 kg CO2

Semi-detached house



~3 years

670 kg in CO2

Large detached house



~3 years

1,120 kg CO2

If you have solid walls-those with a single layer of brick, which predominate in homes built before the 1930s and which you can identify by wall thickness (look for thinner walls) and brickwork style (look for bricks laid lengthwise)-insulating them will be pricier. But because you're already losing more heat through them, the increase in efficiency, and the savings, can be more substantial. A third of British homes have solid walls and according to the National Insulation Association, 45% of the heat in this homes will seep away from those walls.

You can either insulate walls externally, at cost of between £8,000 and £22,000, depending on the size of your home and condition of the walls, or internally, for less money (between £4,000 and £13,000), although with the loss of any current internal decoration you have and requiring the relocation of plugs and fitted furniture.

Energy Savings Trust has compiled data about the savings, in pounds and CO2, from insulating solid walls.

Savings from solid wall insulation

Type of property

Savings per year

Carbon savings per year

Mid-floor flat


520 kg CO2

Mid-terrace house


690 kg CO2

Semi-detached house


1,120 kg CO2

Large detached house


1,870 kg CO2

Given the high cost of solid wall insulation, the return on your energy bills won't be immediate, but you will cut your carbon emissions and potentially increase the resale value of the property and your home will feel more comfortable in winter.

Upgrade your boiler

Boilers can account for between 55 and 60% of your annual energy costs, and you can rack up significant savings by investing in a new, highly efficient one. You may think that replacing a boiler is a contingency reserved only for total breakdown of your current one, but if you have an ageing and particularly inefficient boiler, if could make financial, and environmental sense, to replace it before it fails and see the return via reduced energy bills.

Boilers receive an efficiency grade, from G to A+++, under the Energy related Products (ErP) directive, depending on their efficiency.

For example:

  • Grade G boilers: under 70% efficient
  • Grade F boilers: 70-74% efficient
  • Grade E boilers: 74-78% efficient
  • Grade D boilers: 78-82% efficient

You can consult a search engine to find the efficiency rating of your current boiler, although if its old and hasn't been serviced regularly, it may not to be up to optimal performance and its rating could be lower than expected.

Under Boiler Plus legislation that came into force in April 2018, all boilers manufactured and installed as new in homes must be at least 92% efficient-with an A rating.

If your current boiler receives a grade less than D, it could be worth replacing with one of these new models. The most efficient boilers on the market-condensing models-claim to attain 98% efficiency.

You can make the following savings by replacing poorly performing boiler with an A-rated one, based on your type of property and the boiler you're replacing.

Annual savings from replacing current boiler (grade D-G) with a grade A Boiler

Type of property

Grade G boiler (<70% efficient)

Grade F boiler

(70-74% efficient)

Grade E boiler (74-78% efficient)

Grade D boiler

(78-82% efficient)

Mid-floor apartment





Mid-terrace house





Semi-detached house





Detached house





And the saving from increasing boiler efficiency aren't just in our wallets. According to the Energy Savings Trust, if every house in the UK had a high-efficiency condensing boiler with heating controls, we'd collectively save enough energy to heat 1.9 million homes for a whole year and would keep 6.7 million tonnes of carbon dioxide out of the atmosphere.