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Winter Weather Advice: Your guide to home insulation

In the final instalment of our Winter Weather Advice series, we’re discussing home insulation and how it can make your home feel warmer and improve you energy efficiency.

The high cost of energy in the UK is affecting many homes. Last winter, 64% of people changed their heating habits to keep up with the rising cost of their energy bills. While this can help to save you money, there are other adjustments you can make, such as increasing your home's efficiency.

While this can help to save you money, there are other adjustments you can make, such as increasing your home's efficiency. One of the most effective ways to keep homes warmer in the winter is to ensure that they are properly insulated.

Heat loss due to poor insulation can be one of the key factors behind inefficiency, with many homeowners looking to improve the level of heat resistance in their homes for greater efficiency to help drive down energy costs and to also improve their home's EPC rating. While this will incur an up-front cost, well-insulated homes will continue to benefit from energy savings for decades to come.

Loft insulation

In an uninsulated home, a quarter of the heat you generate is lost through the roof. Adding insulation to your loft is a quick and straightforward job, and you can even do it yourself in cases where the loft is easy to access with regular joists.

The most common method in UK homes is blanket insulation, which uses rolls of foil-backed felt or mineral wool to fill the space between the joists. Another layer is then placed at right angles on top to build up the insulation to the required depth.

Firm insulation boards are added to the sloping ceiling of the loft, while irregular spaces in between joists and around obstructions can be insulated with loose-fill insulation. If you’re planning to get your loft boarded, you can request insulation as part of the process.

Loft insulation cost

The price of a loft insulation project varies depending on the size and type of your property, as well as the level of insulation you opt for. The approximate loft insulation cost for a semi-detached home in the UK is around £440 to top up your existing insulation to 270mm, or £660 to install 270mm insulation in an uninsulated loft. However, an uninsulated semi-detached home could expect to save £355 a year by installing 270mm loft insulation.

Roof insulation

If your loft is being used as an additional room rather than for storage, you should insulate all the walls and ceilings between any heated room and unheated space. Insulation boards should be used on the sloping surfaces of the ceiling and also the walls, with a layer of plasterboard added.

Wall insulation

With the exterior walls of a house being exposed to the air outside, they make up a large proportion of a home’s heat loss. In fact, around a third of the heat lost in an uninsulated house escapes through the walls, so increasing the heat retention of your walls will make a big difference.

Cavity wall insulation

Most homes built in the UK after 1920 are constructed with a cavity wall. Older houses usually have solid, brick walls, but a cavity may have been added as part of previous renovation work.

This consists of two walls with a gap in between them, with the outer wall made from brick and the inner wall from concrete blocks. Cavity wall insulation involves filling this space with a material to trap the heat. We recommend calling a professional installer as this is not something you should undertake yourself.

A professional cavity wall insulation installer will drill into the exterior wall and inject an insulating material into the gap before sealing up the holes with concrete. The insulation is often mineral wool or polystyrene beads, but sometimes polyurethane foam is used instead.

The cost of cavity wall insulation varies depending on the size of your home and the insulating material used, but you can expect to see sizable savings in the future. After insulating the cavity walls, owners of semi-detached houses can expect to see a saving of £395 per year on their energy bills. You should be able to recoup the installation costs in 5 years or less in energy savings.

Solid wall insulation

Solid walls are usually insulated by applying high-density insulation on the internal or external face of the wall, or both.

This is a more costly process than cavity wall insulation, with external insulation being the more expensive of the two solid wall options, but the lifetime savings will also be bigger. Depending on the type of property you have, you could be saving anywhere from £240 – £930 on your energy bills per year.

To reduce the cost of solid wall insulation, you might choose to get just one or two walls insulated or undertake the fitting while you’re having other work completed. For example, if you’re having roof repairs that already require scaffolding, this can reduce the cost of the external insulation process.

Internal wall insulation

More than 30% of homes in the UK are deemed to be hard to insulate with traditional methods, and the majority of these are built with solid walls. It’s important to bear in mind that internal insulation will increase the thickness of the walls, meaning floor space will be reduced by 60mm-100mm for each insulated wall. There are two types of internal wall insulation.

Rigid insulation boards

Insulation boards made from foamed plastic are adhered directly to the interior wall, with additional fittings and joints between the boards to seal gaps and prevent air from getting through.

Stud wall

A stud wall is built onto the interior wall, and the spaces between the studs are filled with insulating material such as mineral wool. This is then covered over with plasterboard ready for decorating.

Tank, pipe and radiator insulation

Metal is a good thermal conductor, which makes your boiler, pipes and radiators prone to heat loss. As well as increasing the insulation in the fabric of the building, insulating your heating system can help to increase your energy efficiency.

This is a cost-effective option that is relatively quick and easy to implement. You can purchase everything you need from a DIY or hardware store and fit them yourself.

Insulating a hot water tank

The hot water in your boiler tank will quickly warm up and radiate heat into the room. If you touch the outside of an uninsulated tank, you will notice the heat that it gives off. A hot water cylinder jacket, which can be purchased for as little as £16, will help to minimise heat loss through the outside of the tank, so the water stays hotter for longer.

Make sure the jacket is at least 80mm thick. If you have an existing jacket that is thinner than this, consider upgrading to a thicker jacket.

Insulating pipes

Pipe insulation helps to prevent heat loss as hot water travels around your home. Also known as pipe lagging, there are a variety of different options available, including polyethylene foam, rubber foam, and fibreglass wrap, with basic options starting at £6. The most common type consists of tubes of hollow foam that fit around pipes like a jacket.

Insulating a radiator

Radiators pump around half their heat output directly into the wall they are attached to, but insulation can improve their efficiency. Radiator reflector panels cost £15–£20 and are quick and easy to install. Consisting of a thin sheet of insulating material with a shiny surface, they are positioned on the wall behind the radiator and work very simply by reflecting heat back into the room.

Draught proofing

By minimising gaps for air to pass through, draught proofing is a quick and inexpensive way to improve the insulating properties of your home and could save you £60 a year.


Draught-proofing your windows can help to avoid heat escaping through the edges and cold air coming into your home. Even if you don’t notice a draught, this inexpensive tip can improve your home’s heat retention. Self-adhesive foam strips can be picked up for £10, while metal and plastic strips vary from £5 – £20 depending on the size and insulation level.


There can be a surprising number of gaps and holes in and around the external doors in your home, which can let in cold air while making it easier for heat to escape. Fortunately, it’s fairly inexpensive to draught-proof letterboxes (£20 – £40), keyholes (£5), and gaps at the bottom and edges of the door (£15 – £50). You can also pick up self-adhesive foam strips for around £5, which are quick and easy to apply.

Cracks in the walls

Even minor cracks in your walls offer an opportunity for heat to escape, so it’s a good idea to seal them. Cement and hard-setting fillers are good draught-proofers for small cracks in walls as they are cost-effective yet strong enough to stop heat from escaping. If there are any serious cracks in your walls, you should speak to a surveyor or builder to determine the underlying cause.

Gaps around floorboards and skirting boards

You might not realise it, but heat can escape through the small gaps between floorboards and skirting boards. To seal these, make sure to purchase a flexible or mastic filler rather than a standard crack filler for walls, as the sealant needs to be able to move with pressure underfoot and flex when the boards expand in the heat.

Making your home more energy efficient

From loft insulation to cavity wall insulation and everything in between, there are lots of ways to help make your home more energy efficient. While some of these options are pretty high cost, you might be able to get support from the government’s ECO scheme. It’s worth remembering that increasing your insulation can have a positive impact on your energy bills and the comfort of your home for years to come.

Another great way to boost your energy efficiency is by upgrading your heating controls, installing a high-efficiency boiler. Along with a well-insulated home, this will help you to further maximise your heating budget.

Read on:

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