Modern masonry homes typically have inner blockwork walls with a gap between these that can be filled with energy-saving insulation to Building Regulations standards. This is one of the most cost-effective upgrades you can make to your home and can significantly reduce energy bills. It is also a good way to cut CO2 emissions and help protect against future energy price rises.
Cavity wall insulation (CWI) is made of a fibrous or loose fill material that is pumped into the cavity space between the brick outer walls of your property. There are a number of different materials available and the best option for your property depends on a number of factors including your budget, energy efficiency needs and the environmental impact you wish to achieve.
EPS (expanded polystyrene) beads are the most commonly used type of cavity wall insulation. They are sourced from carbon polymers that are melted and then injected into the wall cavities using a bonding agent. This is a very popular choice of insulation best cavity wall insulation new build, particularly as it has a relatively low thermal conductivity and is cheap to install.
One of the most environmentally friendly options available, mineral wool is a natural and renewable material made from fibres extracted from sheep’s wool and other animals. This type of insulation has a slightly higher lambda value than EPS beads but is still fairly favourable at around 0.03 W/mK. It also has the added benefit of being a great moisture barrier, which will help to prevent damp and condensation in your home.
Similar to the mineral wool, cellulose fibres are derived from a natural and sustainable source. The advantage of cellulose is that it has a very high R value of 4.40, meaning that it retains heat well and is very cost-effective. It is also a very lightweight material, making it easy to install.
Cellulose is often chosen as a top-level choice for new build projects as it is extremely durable and can easily be installed alongside other building materials such as timber frame, metal framing or concrete. This means it can provide both a thermal and sound barrier, which is very important for new builds.
It is worth noting that although insulating the cavity walls of your property will help to keep more heat inside your house, it will also increase air circulation and can lead to condensation in some cases. To avoid this, extra ventilation may need to be installed as part of your retrofit. You can usually find a professional installer who will offer this as part of the service and can also advise you on simple lifestyle changes to manage humidity, such as opening windows when cooking or drying clothes outside where possible.
As mentioned above, upgrading your properties insulation can significantly reduce your energy bills and CO2 emissions. You should also be aware that if your property has already been insulated, it’s likely that the minimum energy performance standard (EPC rating) will have been achieved by the installer. It is therefore recommended that you have your CWI upgrade surveyed by an independent energy assessor to develop both short and long-term plans to improve the overall energy efficiency of your property and maximise the benefits of your investment.