External Wall Insulation
The Benefits Of EWI

There are numerous benefits of external wall insulation systems and reasons why you should consider installing EWI – whether this be in your new build or refurbishment project. We have detailed the main benefits below:

EWI Improves Thermal Performance

It goes without saying that an external wall insulation system will, first and foremost, improve thermal efficiency … often significantly.

Thermal performance is measured as a U-value to represent the heat lost per square meter of wall. There are strict regulatory requirements when it comes to both new build and retrofit upgrades to support Government emissions targets. In simple terms, the closer the U-value is to zero the least heat is being lost through the walls and the more energy efficient the property will be.

To give you an example of how much EWI can improve a property let’s take a typical old solid wall property in its original state. In this case it is expected that a standard EWI system would be able to improve the U-value from around 2.70 W/m2K to below 0.30W/m2K (the current minimum requirement for retrofit). That’s a really significant and noticeable improvement!

Increasing the thickness of insulation (even up to 400mm) can result in even greater efficiencies.

Find An INCA Member

Whatever the nature of your involvement in an EWI project, whether it be new build or refurbishment, small or large, INCA have members who can help.

  • Home Owners
  • Social Landlords
  • Specifiers
  • Main Contractors

Insist on EWI system quality and technical competence – choose INCA.

EWI Reduces The Carbon Footprint

Obviously, improving thermal efficiency means reducing carbon emissions which means that, not only will your own carbon footprint improve but you will also be supporting the Government towards their target of Net Zero by 2050.

External Wall Insulation Reduces Energy Bills

An improvement in energy efficiency and reduction in heat loss is obviously going to result in a reduction in heating costs. You’re not going to be paying for all that heat that was being lost through the walls.

The Energy Saving Trust estimate that up to a third of the heat produced by a central heating system is lost through the walls and the roof. They go on to suggest that, by installing an external wall insulation system, heating costs can be reduced by up to 40% is some cases.

It’s difficult to generalise as to exactly what this will mean of pound note terms as every property will be different but, as a general guide, a mid-terrace property can save over £160 per year, a simi detached over £240 and a typical solid wall four bed detached property can save over £450 a year by installing a standard 90mm EPS external wall insulation system.

These figures ware estimated prior to the significant energy price increases of 2022.

EWI Improves Thermal Comfort

Thermal comfort is all about maintaining a comfortable temperature during all seasons and weather conditions.

In the cold and winter an EWI system will trap internally generated heat and keep it inside. In the hot sun it will reflect externally away solar generated heat and hence prevent it from getting too hot inside.

External Wall Insulation Reduces Outside Noise

Whilst not the primary function adding external insulation (particularly mineral fibre) has an added benefit of providing improved acoustic insulation which will cut down external noise, in the same way that double glazing does, making for a quieter living environment.

EWI Reduces The Risk Of Condensation And Damp

By insulating the walls externally, heat is trapped on the inside meaning that the temperature of the internal walls will increase. Because airborne moisture is attracted to cold walls his thereby reduces the risk of condensation forming.

Externally, an EWI system will provide a protective and waterproof barrier which will automatically help protect against penetrating damp.

EWI systems are also breathable which means they allow for the continuous movement of air and will therefore reduce the risk of moisture build-up.

EWI Minimises Thermal Bridging

Thermal bridging is also known as cold bridging and refers to any area of a building which has a significantly higher level of heat loss or transfer that the immediate surrounding areas.

Because an EWI system is designed to provide a full and seamless envelope around the outside of a building such cold spots can be minimised or eliminated.

EWI Improves Aesthetics

There are many different finish options to any EWI system – an infinite number of different colours, textures, effects and combinations.

This means that a property (and, indeed, entire communities) can be modernised and completely transformed. Different textures and colours of render, brick or stone effect, dash or aggregate finishes are all options and different features can also be created / replicated to create stunning designs which will stand the test of time.

External Wall Insulation Protects

Because EWI is wrapping the full exterior of the building it means that the existing fabric of the building is protected from the elements thereby protecting it from the environment and against the effects of weather and hence prolonging the life of the building.

External Wall Insulation Adds Value

Not only are you making your property more energy efficient and cheaper to heat you are also improving its EPC (energy performance certificate) rating which will have a positive effect on the property value.

Government data published in 2013, showed that moving from EPC band G to E or from band D to B increased the average value of a property in England by approximately £16,000.

Not only that though, making it look better externally will add additional value and make it more attractive in the housing market.

External Wall Insulation
All You Need To Know