Adding external wall insulation (EWI) to your house is an effective way to save energy by reducing the amount needed to heat your home, saving you money on energy bills as well as lowering your carbon footprint.
Uninsulated walls allow around a third of the warmth pumped into a house to leak out (according to the Energy Saving Trust**), making your central heating system work harder to maintain a comfortable temperature. External Wall Insulation will help to keep heating costs low because your boiler won’t need as much energy to keep a cosy environment.
External Wall Insulation will increase the thermal performance of a building without compromising on valuable internal floor space. Installing EWI doesn’t disrupt things inside your property in the way that internal insulation would. It can also help to improve sound resistance.
By insulating externally, the large thermal mass of the masonry walls slowly heats up. The walls then slowly give out that stored heat and because there is insulation on the outside of the wall the majority of the heat is redirected back into the house.
As an External Wall Insulation system is finished with an EWI Silicone Render system, your property will benefit from a fully refreshed appearance.
EWI Silicone Renders come in a wide range of colours, and can be matched to any RAL, NCS or Pantone colour. So coupled with their protective performance means no re-painting is required, which can save significant amounts on redecorating costs over future years.
Unlike internal insulation, External insulation minimises the occurrence of cold bridging as it wraps the entire house from the outside, separating the cold air from the masonry walls and thus minimising any cold bridges (a bit like putting a coat on your house).
Any improvement for your home relating to energy efficiency is beneficial. Improving the EPC rating of your property will have several benefits. The steps you take to improve your EPC rating will improve thermal comfort and save you a sizeable chunk on your energy bills. We are going to examine what the EPC rating scale is and how it can impact you.
In summary, an EPC rating is a review of a property’s energy efficiency. The rating indicates to homeowners, renters, and new buyers how much their energy bills will cost in their new property.
The EPC rating of the house will depend on two variants:
The acronym stands for Energy Performance Certificates and are valid for a period of 10 years. If you are looking to sell or rent after this period, you will need to get your EPC certificate renewed. A valid EPC is necessary for all properties due to be sold, except for listed buildings. It can also instruct people when deciding between properties. The easy comparison presented by the scale will inevitably always push a person towards properties with a higher EPC rating.
The major reason to improve the EPC rating of your home is the potential return when choosing to sell. However, the benefit for improving your rating whilst living at the property is also worthwhile. The vast savings on your energy bills, especially given the current rising costs make the investment worthwhile. Some changes may be extensive and expensive, but there are also low cost solutions. We will discuss these solutions below.
The current legislation states that the EPC rating of a property can be E. However, changes are coming:
Minimum EPC rating to be raised from E to C. The plan is to enforce this from 1 April 2025 for new tenancies, and from 1 April 2028 for existing tenancies. The government says this would be sufficient to bring more than 90% of D-rated properties up to a C rating, as well as nearly 60% of E-rated properties.
Kirsty Burnham; accessed at https://www.nrla.org.uk/
The most common and most popular recommendation to improve the EPC rating of a property is to install some form of insulation. The options are either external wall insulation, internal wall insulation, or cavity wall insulation. All have their specific benefits and issues. They also impact the savings on your bills differently.
We would always champion external wall insulation as the best solution. It does not impact the internal floor space or cause damp issues in the wall cavity.
Improving the efficiency of the walls of a building is typically the easiest way to hit the C rating on your EPC. This is due to two reasons – firstly the walls often account for the largest surface area, and secondly because you can take very low performing walls efficiency wise, and make them super high performance.
Of all the types of wall insulation (cavity, internal and external wall insulation), external wall insulation normally comes out the winner as you can add so much insulation without any real upheaval – we would recommend adding 90mm of EPS or 100mm mineral wool to hit the u-value of 0.3 to adhere to modern building regulations.
Alan Bouquet – London EPC
Savings will naturally vary depending on the property and the thickness of insulation you install. However, with the rising bills, you can expect close to £1,000 worth of saving on your bills with external wall insulation.
EPS insulation is a high-performing and cost-efficient insulation material. When installed on a property, EPS very easily upgrades the thermal properties of a building – improving U-values and reducing the risk of water penetration and condensation.
EPS boards can be used on masonry and system-built properties as well as with EWI Pro render systems. It is designed to be applied externally using EWI Pro adhesive and mechanical fixings. EWI Pro EPS boards are available in a broad range of thicknesses (from 20mm to 200mm – going up in 10mm increments).
Kingspan K5 external wall board is a premium phenolic insulation board for external wall insulation systems. This product’s key feature is that it is great for saving space in your EWI installation. The insulation boards have a rigid phenolic core, which offers excellent thermal capabilities, and is ideal for use with our thin coat renders to create a highly effective insulation system.
Kingspan K5 external wall boards offer upgraded thermal performance to other insulation materials on the market. Therefore, they are ideal for maximising performance without sacrificing too much external space.
Mineral Wool insulation offers both improved thermal conductivity and acoustic insulation. One of the most appealing aspects of this type of insulation is that it offers outstanding fire resistance, because Mineral Wool is non-combustible; it’s therefore ideal for providing firebreaks when insulating high rise buildings. This is because the insulation itself acts as a fire barrier, helping to slow down the rate of flames without contributing to the fire. Mineral Wool systems are also a premium system because of they offer a high level of breathability; the presence of fibres and moisture repelling compounds within the material help to wick moisture through and away from the substrate.