What is Insulation and How Does it Work?

Did you know only a third of homes in the UK have updated their insulation?  With energy prices soaring the best investment to get ready for the winter is to update your home's insulation.

25 April 2022 | Make my home greener

Why should I insulate my home?

Many of us think that once our homes are insulated, then there's no need to update it, which isn't true. However, for your home to be as energy-efficient as possible and save money on your energy bills, you may want to consider updating your insulation to meet the current building regulation.

We've recently researched the UK's insulation, and the facts speak for themselves. Whilst we're happy to spend money on upgrading our phones, TVs, kitchens and cars, we don't invest in updating our insulation.

What did our insulation research tell us?

  • Only 7.5% of UK homes have an insulation age of 2002 or younger. Meaning a huge number of houses are not meeting the current insulation regulations.(1)

  • A lot of us live in homes built before 1976. Only 0.03% of these homes have been updated with additional energy efficiency measures, which means the property meets the 2002 insulation regulations.(1)

  • Consumer research of 2,000 UK households commissioned by us to support the study found that despite the average household living with insulation standards dating back at least 46 years, only a third (37%) of homes have ever updated their insulation.(2)

What are the benefits of insulating my home?

  • Get ready for winter and help save - It's strange to be thinking about winter already. However, with less than six months until Ofgem announce the next energy price cap. Improving your insulation measures offers the biggest opportunity to cut your energy bills. Based on the current energy prices, loft insulation alone could save you up to £580 a year if you live in a gas-heated, detached home or up to £255 if you live in a gas-heated semi-detached property.(3)
  • Stop wasting heat - If your loft insulation is inefficient, a quarter of your home heat escapes through the roof.
  • Energy-efficient homes - Sounds obvious but installing better insulation means it could help you increase your home's EPC rating, which adds value to your property and make it easier to sell. According to data analysed by the BBC, nearly two-thirds of UK homes fail to meet long-term energy efficiency targets. More than 12 million homes fall below the C grade on Energy Performance Certificates (EPCs) graded from A-G. Find your current EPC rating.
  • Quick to install - Loft or attic insulation is easy to install and causes minimal disruption to your home
  • Maintenance-free - It's maintenance-free once installed

Find the insulation age of homes in your area

Home insulation infographic showing where heat escapes from a house. Can't see the image? Read what it says: https://www.edfenergy.com/sites/default/files/insulation_homepage_illustration.pdf

What areas are best to insulate?

Floors, lofts, pipes, windows and walls are the main areas where hot air will escape and cold air can come in.

There are many simple yet effective ways to insulate your home, which can significantly reduce the amount of heat you waste whilst lowering your heating bills.

Explore how this can be done in every part of your house below.

fibreglass loft insulation roll in attic

Roof and loft insulation

Installing loft insulation is as simple as unrolling a rug. A mineral fibre material is laid between the joists and then over the joists in your loft or roof. This thick material captures heat normally lost through the roof and stops draughts getting in.

If you already have loft insulation, you could still benefit from a top-up. If your insulation is 100mm or less, you can increase it to the recommended level of 270mm.

Cavity wall insulation cross section

Cavity wall insulation

To start we need to find out if your home is suitable for cavity wall insulation. To assess this we drill small holes in your outside walls. If it's suitable for your property, the cavity between the inner and outer walls is then filled with insulating material. The holes in the brickwork are then filled in again. The installation process takes just a few hours and should come with a Cavity Insulation Guarantee Agency (CIGA) guarantee.

floor insulation under concrete

Floor insulation

According to the Energy Saving Trust, a semi-detached house could save £75 a year on heating costs if you have well-insulated floors.(4)

You can insulate your floors either by laying down new insulation or by sealing draughts and gaps. You can use a sealant from a hardware store to seal up gaps but if you need proper underfloor insulation, first you need to work out what kind of floor you have.

House after insulation fitted
House before insulation fitted

Solid wall insulation

Solid wall insulation keeps older homes warmer for longer. This can transform the look of your property and stop heat loss – it's like wrapping a huge blanket around your home. Solid wall installation normally takes between 2-4 weeks and can be done with very little disruption because no interior work is needed.

copper pipe foam insulation

Pipe insulation

Pipe insulation is when you cover your pipes with foam tubes or a reflective wrapping. It's a great idea to insulate any exposed pipes leading from your tank to your boiler to keep the heat in.

Foam covers keep your pipes snug – and therefore they lose less heat. You can get different shapes and sizes from any hardware shop and they're usually a cheap option for keeping that extra bit of heat in.

Pipe insulation types

  1. Pipe wrap: this is a foam usually that fits onto your pipes with a slit so you can easily put it on. Sometimes this has a reflective silver outer layer which is an added layer to keep the heat in.

  2. Pipe lagging: this is a fabric alternative for your pipe insulation, made of very thick material and is usually more expensive than the foam option.

a man uses a glue-gun like apparatus to put draught proofing paste onto a window sill


Draught insulation is a cheap and effective way to save you energy and money by stopping heat escaping from your home. By blocking any gaps where heat can escape and cold air can get in, you'll keep your home temperature just right all year round.

Making sure your home has door insulation and window insulation means you keep the cold air from entering your home and the warm air from escaping. These can all be blocked up with different kinds of draught excluders. There's lots to choose from.

It's really important not to block any deliberately placed ventilation points – such as extractor fans, grilles or wall vents.

a hot water cylinder jacket

Insulating tanks

Lagging water tanks and pipes and insulating behind radiators reduces the amount of heat lost, so you spend less money heating water up, and hot water stays hotter for longer. Insulating your hot water cylinder is one of the easiest ways to save energy and, therefore, money.

If you already have a jacket fitted around your tank, check the thickness. It should be at least 80mm thick; if it isn’t, consider buying a new one. Upgrading your hot water tank insulation from 25mm to 80mm thick, using a British Standard jacket, could save you around £20 a year, which is more than the cost of the jacket.

Slipping pipe insulation around your exposed hot water pipes will keep your hot water hotter for longer. Insulating pipes is easy if the pipes are accessible; if your pipes are hard to reach, you may need to engage a professional.

How we're helping customers who need extra support with insulation

We're offering eligible customers home improvements like insulation through the Energy Company Obligation scheme.

What is the Energy Company Obligation scheme?

The Energy Company Obligation (ECO) Scheme was set up in April 2013. The purpose of the scheme is to help eligible customers make their homes more energy-efficient by installing free energy-saving measures and heating improvements. This helps customers keep their homes warm and keep their energy bills down.

The new ECO4 scheme will run between April 2022 and March 2026. Eligible EDF customers will be able to access a range of energy efficiency improvements that will help them improve their home's EPC ratings to a rating of C or above.

Customers will need to take a package of energy efficiency improvements rather than just one. We're working on what these will be. Eligible customers will have a survey carried out on their homes to make sure their property is suitable for these improvements.