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Insulate your home and lower your energy bills for good


With temperatures dropping and energy prices forecast to rise yet again in April, you may be wondering how you can lower your heating bill. In this article, we look at how to insulate your home. 

In this article:

What is insulation?

Insulation is any material that stops heat from your home being lost to the outside air, or to a neighbouring property. Insulation comes in many forms, but most commonly involves either solid foam boards, synthetic wool made out of stone or silica, or sprayed foam.

How do you insulate your home?

1. Wall insulation

There are two main types of external wall on houses in the UK – cavity walls and solid walls. Cavity walls are insulated by inserting material (usually wool, beads or foam) into the cavity. Solid walls are insulated by attaching a layer of material to the  inside or outside of the wall. 

Graphic showing cavity walls and solid walls

The cost of cavity wall insulation ranges from £400 to £1,800, and will save a typical home £50 to £200 a year at current energy prices. Solid wall insulation will set you back more, costing upwards of £8,000, for a saving of £100 to £300 per year (Source: gov.uk). 

External wall insulation being fitted

Around 70% of homes with cavity walls have already been insulated, while only 10% of solid walls have.

2. Loft insulation

If you have access to your loft space, you can save a lot by insulating your roof. This is usually cheaper than other types of insulation. It involves laying mineral wool between the joists of your attic floor, or inserting insulating boards or foam between the rafters of the loft ceiling. Using insulation between joists will increase the warmth of your home but mean the attic is colder, which can increase the chances of damp. The Energy Saving Trust has a plethora of advice on installing loft insulation properly.

Mineral wool loft insulation

3. Floor insulation

Properties at ground level can lose large amounts of heat directly through the floor. If you have solid, concrete floors, you can reduce the effects of this by laying down insulating panels on top of the floor. You can buy the insulating panels from most local hardware stores, but because this will change the level of your floor, installing solid floor insulation is normally left until more extensive building works are taking place.

If you have suspended floorboards, you could benefit from a layer of mineral wool or foam underneath them. You may need to lift up the carpet so that you can access the floorboards. If there is no access or space beneath the floorboards for an installer, you may also need to lift up the floorboards to fit the insulation, before replacing them again.

Alternatively, a company called Q-Bot uses intelligent robots to spray insulation foam to the underside of a suspended floor. To check your homes eligibility and learn more, click here.

4. Windows

Despite double glazed windows being the ‘go-to’ method of reducing heat loss through  windows, it is not always:

  • Possible – if you have ‘sash’ windows (two or more frames that slide over one another to open the window), it may not be possible to keep the same design if you choose to double glaze.
  • Allowed – you should check with your local planning office to see if there are any restrictions on your property – for example if you’re in a conservation area or in a listed building.
  • Affordable – Double glazing can cost upwards of £5,000 depending on the size of your home, but may only generate savings of £50 to £200 a year.

Other, cheaper options for reducing heat loss through your windows include ‘secondary glazing’. This is where an additional window is fitted in between the window and the room. This window can be made from a variety of transparent materials but is usually made of glass. Other options to reduce heat loss through windows are thick curtains, thermal blinds, or shutters, which can help keep heat in in the evening and at night.

How do I know if my house is insulated?

The most obvious sign of poor insulation is that its hard to warm your home – and keep it that way. If you’re unsure, it’s worth checking whether your home has a valid Energy Performance Certificate (EPC). EPCs are required before any home can be sold or rented out, and calculate the efficiency of a home on a scale from A to G. 

If your EPC has expired, or your home doesn’t have one, you can infer a lot from common building practices at the time it was built. Homes built before 1920 are unlikely to have much by way of insulation unless it has been added since. After 1920, cavity walls became the norm. This resulted in some improvement, but it was only in the 1970s that it became common practice to fill these gaps with insulating material. 

The thickness of the wall is another good indicator: walls that are less than 26cm wide are usually solid walls and likely don’t have a cavity, so won’t be insulated. 

Lofts are now always built with insulation. However, the suggested amount of insulation has increased over time. You can measure the depth of the existing insulation using a tape measure – loft insulation should be at least 270mm thick. You should also look out for gaps in insulation as this will leave heat with an easy escape route. 

What about damp?

Finding ways to insulate your home will prevent warmth escaping, but if done badly, can result in increased condensation inside your home, which can lead to mould. If you’re waking up with condensation on the inside of your windows or walls, this is an indication you may have a problem.

The solution is purpose-built vents that deliver air flow in a controlled way, avoiding chilly draughts and ensuring your home stays healthy and dry. It’s worth checking to make sure any vents in your own home haven’t been covered or disabled, particularly in rooms with open fires or flues (including gas fires), or where a lot of moisture is produced, such as bathrooms and kitchens. You can also prevent dampness by opening windows (if it’s not too cold), or by wicking moisture away – using the extractor fan on your oven when cooking or by purchasing a dehumidifier.

If you’re looking at installing insulation, make sure you use a qualified installer, and that they carry out a ‘pre-condition report’ to make sure insulation won’t cause any damp issues.

What help can I get to pay for insulation?

The government announced this week that there will be further support available for homes that don’t already benefit from any other government support. The new initiative, known as ‘ECO+’, accompanies the already-announced ECO4 scheme, which runs for four-years from April 2022 to March 2026 and offers help to low-income and vulnerable households. The ECO+ scheme aims to provide rapid installation of energy efficiency measures to a wider pool of households. This includes both those on the lower incomes and those on higher incomes who live in poor performing homes.

To be eligible, households need to:

  • Be in the lower council tax bands (A-D in England, which is 81% of properties, A-E Scotland and A-C in Wales).
  • Have an energy performance certificate (EPC) rating of D or below.

More information on the ECO+ scheme can be found here.

Existing support includes the ‘Help to Heat’ initiative which comprises a £12bn support package. This package includes the Boiler Upgrade Scheme, Home Upgrade Grant and Local Authority Delivery Scheme.

Cheaper ways to reduce heat loss from your home

If you’re looking for a quicker, easier way to reduce heat loss and can’t afford to insulate your home, there are a vast range of items available to draught proof your home and retain warmth. These items range from £5 to £50 but could save you up to one hundred pounds on your annual energy bill. Items to consider include:

  • Adhesive sealant
  • Water tank jackets
  • Radiator reflectors
  • Window film
  • Chimney balloons
  • Door snakes

How your employer can help

Your employer can help you procure these items, as well as a vast range of other energy saving gadgets by signing up to our ‘energy toolbox’ service. Ask your employer to book a call to learn more.

Professional guidance on home efficiency

If you’re uncertain about the energy performance of your home, want to know how to insulate your home, or are wondering about other ways to reduce your bills, you can also book one of our home energy assessments – for more information, visit our dedicated page on home energy.