Installing external wall insulation (EWI) is the process of fixing insulation boards to the external walls of your property, before applying a layer of thin coat render on top as a decorative, weatherproof finish.
Commonly, EWI is installed on UK homes to help improve the thermal performance and energy efficiency of the property in the winter months. However, EWI actually maintains the thermal comfort of a building year-round – so you can expect a cool house in the summer and warm one in the winter.
How Does External Wall Insulation Work?
External wall insulation slows the rate of heat transfer through the walls of your property. Insulation materials such as EPS have high air content, which means that heat can very easily become trapped within the material. As a result, heat from inside the home will struggle to escape, and vice versa – heat from outside will not be able to penetrate into the home.
Solid wall homes suffer enormously when it comes to heat transfer. This is because there is only one layer of brick, so there is very little standing in the way of letting all the heat out/in. In these situations, it’s worth investing in EWI to help maintain a comfortable environment.
Wood Fibre Insulation and Sun Protection
Wood Fibre insulation is particularly good at providing sun protection on lightweight structures. Thermal mass is the ability of a material to absorb, store and radiate heat energy; natural building materials such as Wood Fibre insulation have a high thermal mass compared to insulation materials like EPS. This means that on hot days where solar gain is at a maximum, Wood Fibre insulation will keep the building significantly cooler.
Lightweight building structures such as timber frame or steel frame will benefit from this immensely, as in these types of buildings it only takes a small change in climate for the internal temperature of the building to be affected.
Why Is EWI Useful in the Summer?
Having a nice cool environment to escape to on a hot day is pretty important. Air conditioning systems can certainly achieve this, but at a steep cost; the continuous use of air con and fans means that your energy bills will be needlessly expensive. External wall insulation will increase the efficiency of these systems by improving the airtightness of your property so that the cool air stays inside, and by absorbing the heat from the sun and subsequently preventing it from getting inside.