Eight ways to insulate your home and save money

Along with the wintry chill come thoughts of making our homes as cosy as possible. But no one wants huge heating bills. The practical answer is good insulation. Not only will it cut your costs in the long term, it also helps to reduce a build-up of damp and mould.

A new study by the Finnish electricity comparison site Sähkösopimukset analysed data from the Department for Levelling Up, Housing and Communities on energy efficiency certificates (EPC) issued across the UK during July 2024. They found that the average UK home has a 68.7 out of 100 rating, equal to a D-rated EPC, which likely means inadequate heating, insulation and windows.

Lisa Stanley Mann, the co-founder of sustainable money site good-with-money.com, recently wanted a thermal imaging heat loss survey on her home. She turned to Retrofit West in Bristol, which were offering discounts for residents. She paid less than £150 for a three hour assessment and was impressed with the advice they gave her on sealing the gaps where her walls meet the floor, plugging her chimney and opting for magnetic secondary glazing. “It was an inexpensive way of getting expert guidance and lots of practical ideas,” she says, but you can also check local government websites or energy suppliers for home energy saving incentives.

With some investment and a little insider know-how, there are a variety of upgrades you can do to insulate the nippier parts of your home.

Sort out your roof

Insulating your roof may be the best thing you do, as it could reduce your heat loss by half, and in most cases, it means minimal disruption. The Energy Saving Trust recommends rolls of mineral wool insulation (270mm depth) between the joists on the loft floor – specialist companies charge around £1,000-1,500 for this service.  You can also fit insulating boards over the rafters on the roof itself, but this can be costly and difficult, and should only be done if the roof is leak free and in good condition. In a semi-detached house, insulating your roof could save you around £230 a year in energy bills.

Loft conversions need to adhere to building regulations and be well insulated otherwise your heat will escape through the roof. You will want to consider how the space is ventilated; you may need vents added to enable air flow and prevent moisture problems.

Warm up walls

Andrei Tartza, the founder of award-winning home insulation company, Pioneer Insulation explains that “houses built before the 1930s tend to have solid walls, and opting for external wall insulation provides a layered shield (in the form of foam or mineral wool boards and then render) that not only gives the building incredible kerb appeal and increases its value, it protects your home, long term, from the elements outside and stops heat from escaping. It also helps to regulate the temperature indoors throughout the year and will work towards stamping out condensation, damp and mould, and can improve soundproofing. The cost for a semi-detached house starts from £25,000 and can save you more than £800 per year on energy bills. But, most importantly, your living experience is much more comfortable and healthy.” If rendering is not your thing, you can opt for your solid walls to be internally insulated with rigid plasterboard sheets.

Houses built after the 1940s tend to have external cavity walls (an air gap between the internal and external structure) and so can benefit from injecting insulation material – mineral wool or polystyrene beads – from the outside into this space.  Opting for cavity wall insulation costs up to £3,000 and could save you around £250 a year in a semi-detached house. More modern builds (1990s onwards) generally will already have insulation.

Check the Energy Saving Trust website (energysavingtrust.org.uk) for recommended installation associations, like the National Insulation Association. The British Board of Agrément and the Installation Assurance Authority are industry certification bodies and a stamp of credibility for businesses.

The Great British Installation Scheme is a government initiative that aims to upgrade the least energy efficient homes in England, Scotland and Wales. This grant applies to properties that have a council tax band of A to D and would cover a proportion of the total cost. See gov.uk/householdenergy for details.

Other schemes include the Health Conditions Grant where homeowners can receive substantial funding towards the cost of installing external wall insulation if they suffer from a severe or long-term health condition such as a cardiovascular condition, a respiratory disease, limited mobility or immunosuppression.

More welcoming windows

Well-fitted lined curtains, thermal blinds, wooden interior shutters, and window insulation film are all affordable options for preventing wintry gusts blasting through loose frames. Richard Dollar, the managing director at The Sash Window Workshop, says: “If your windows are currently single glazed, and you are not restricted by planning regulations, double glazed timber windows are the best option for reducing the cost of heating bills, diminishing external noise and improving the warmth of your home (Prices depend on so many variables but a ballpark figure is around £1,200-2,500 per sash window).

“However, not all new windows will be made to the same standard. It is important to check the U-value (your supplier should be able to do this), which measures how much heat is transferred through the window. The lower the U-value, the better the heat retention. Air penetration is also worth checking as this measures the heat loss from leaky windows. The lower the air penetration rate, the less heat will be lost.

“Alternatively, if your windows are in a good condition, draught-proofing (sealing any gaps with foam or brush strips, or silicone) can help prevent cold air coming into your home. Research by English Heritage found that air infiltration through a sash window, which is in good condition, can be reduced by as much as 86 per cent by draught-proofing.”

Rachael Munby, the chief marketing officer at Anglian Home Improvements, adds: “Choosing double or triple glazed windows can be tricky as every home is different and it’s important to assess your windows room by room. The most effective option is to mix and match on triple and double-glazed windows, depending on which rooms see the most natural sunlight. For example, install double glazing in the warmer south-facing and west-facing rooms where you will benefit from harvesting the sun’s energy and install triple glazing in the colder, more shaded north or east-facing rooms where you can maximise retaining the energy you generate inside your home.”

The Energy Saving Trust says: “By installing A-rated double glazing to windows in an entirely single-glazed semi-detached gas heated property, you could save £140 a year.” And the Glass and Glazing Federation have an online tool to calculate how much energy and money you could save by replacing your windows.

Seal that door

Scrutinise your doors, especially the front door, for any cracks, gaps or draughts.

Doing it yourself is straightforward and inexpensive – opt for a metal disc that sits over your keyhole, buy an interior letterbox flap, choose brush strips along the bottom of the door, and use foam or silicone adhesive seals to fill any gaps – you can buy sheep wool draught seal tape for doors and windows for £7.50 from Chimney Sweep.

Keep internal doors closed whenever possible and there is nothing wrong with a good old-fashioned cloth draught excluder for along the bottom of a leaky door. Etsy has a ton of lovely ones.

Stuff the fireplace

If there is a roaring fire in it, then great. But decorative or unused fireplaces can be draughty when the weather outside is blowy. Plus, if you have your heating on, they can draw the warm air out of the room. A cheap and easy option is to install a draught excluder into the chimney (obviously take it out if you do light a fire). They resemble a big bath plug, usually made of wool, with a handle for easy removal and cost around £25. At a similar price, a more permanent chimney “balloon” inflates and presses against the walls of the chimney, minimising the loss of warm air.

Also, you can get an external chimney cap fitted. These are usually terracotta and cost around £30, but they do need to be fitted by a professional to the top of your chimney. They help prevent draughts and moisture (and even birds) entering the room. Both options could save you about £60 a year in bills.

Keep it cosy underfoot

You may feel it’s worth going for underfloor insulation, which isn’t quite as pricey as solid wall insulation. Even so, it is a long-term investment and only really works in period homes, which tend to have suspended timber floors. In a semi-detached house, it could save you up to £70 a year in energy costs.

Changing your flooring could be another option. Fitting carpet, or laying down expansive rugs, will reduce floorboard draughts, but deciding on a more robust option could be the way forward.

Rob Weems, the director of Solid Floor, is an expert in timber flooring. “Wood is a natural insulation material,” he says. “So if you install hardwood floorboards or parquet in your home, it will be naturally warm under foot. At night when you turn down the heating, a timber floor will release the heat absorbed during the day, so keeping your home warmer for longer at a lower cost. When installing a new timber floor it is also a good opportunity to insulate under the original subfloor or install underfloor heating – further compounding the benefits.”

For more practical rooms, like kitchens and hallways, Lee Thornley, the founder of Bert & May, says: “Floor tiles, particularly porcelain, have excellent properties that help to maintain consistent temperatures and keep energy costs down. In the cooler months, especially when combined with underfloor heating, tiles can retain and distribute heat. Additionally, tiles are durable and low-maintenance, making them a cost-effective design choice that lasts the test of time.”

Reflective radiators

Reflective aluminium panels placed behind radiators that sit on an external wall will help to prevent the heat escaping through the wall; instead, pushing the heat back into the room. An inexpensive outlay – around £20 – there’s no denying they are an appealing option.

Put a jacket on

Fitting a special jacket (a British Standard jacket is 80mm thick) around your water tank is a quick and easy way to reduce heat escaping, which means you spend less money heating your water and it stays hotter for longer. The jacket will be about £20-40 and could save you £40 annually in energy bills. Check gov.uk/saveenergy for details.

If you want to push things further, the Energy Saving Trust adds that: “The Boiler Upgrade Scheme is a UK government initiative aimed at encouraging people in England and Wales to install heat pumps. This scheme offers grants of £7,500 towards the cost and installation of three types of low carbon heating systems: air source heat pumps, ground source heat pumps – including water source heat pumps – and biomass boilers.” But heat pumps do not suit all properties (flats and small terraces; heat pumps need space to function) and because they run on electricity, which is more expensive than gas, there is some scepticism about running costs.