What does an Energy Retrofit involve?
An energy upgrade or “Deep” Retrofit of a home involves carrying out multiple energy measures all at once to achieve a more energy efficient home.
Firstly, you will need to reduce the level of heat loss from your home. This can be achieved by improving the fabric or “envelope” of the dwelling. This involves some or all of the following: wall insulation, roof insulation, floor insulation, window & door upgrades.
The next step is to look at your heating system (ideally to support the transition away from fossil fuels). The typical heating system installed on a domestic retrofit is an air-source heat pump, in addition to upgrading the heating controls.
The retrofit also includes mechanical ventilation to maintain good indoor air quality (Shift away from Natural ventilation strategies, or traditional “hole in the wall”)
Other renewable energy technologies such as solar PV may also be appropriate for your home.
Energy Efficient Measures
Up to 35% of the heat in your home can be lost through the external walls. This heat loss can be reduced by insulating the walls to keep more heat inside your home.
There are three different methods to insulate walls: cavity, external and internal insulation. These can be used on their own or in combination depending on the existing construction.
Additional ventilation may also be required following installation, in order to ensure adequate ventilation in your home.
Cavity wall insulation
If your home has cavity walls which are not insulated or only partially insulated, then cavity wall insulation is an easy, cost effective ﬁrst step to reduce heat loss.
This process involves pumping insulation into the cavity. A series of small holes are drilled in the wall at regular intervals on the outside, with insulation inserted “pumped”. The holes are then filled in order to match the original wall.
External wall insulation
External wall insulation is generally the preferred option for solid masonry walls. It can also be used with cavity wall insulation to further improve the performance of your external walls. This involves wrapping the external walls with rigid insulation.
Internal wall insulation
Internal wall insulation is often considered when external or cavity wall insulation isn’t an option (i.e. for some protected structures). FYI – Internal wall insulation is more disruptive, when compared to external wall insulation.
Internal insulation (often referred to as ‘drylining’) usually involves fixing insulation boards to the inside of the external walls and covering them with a vapour control layer, plasterboard and skimcoat finish As the boards are applied to the inner side of the walls, there will be some loss of space in the rooms.
Other upgrades that can be made include:
- Roof Insulation
- Floor Insulation
- Windows and Doors
- Heat Pump
- Solar PV
What are the main benefits of a domestic energy upgrade?
- Improve the thermal comfort of your home by reducing unwanted heat loss and draughts.
- Reduce air pollutants from entering your home, ensuring improved indoor air quality
- Reduce your heating bills, by increasing energy efficiency and utilising renewable energy systems.
- Use government grants available to help pay for energy improvements to your home.
- Reduce your greenhouse gas emissions by having a more energy efficient dwelling
What is a Building Energy Rating (BER)?
A Building Energy Rating (BER) grades the energy performance and carbon emissions of buildings, on a scale of A to G, with A being the most efficient, and EW being the least efficient.
How is a Building Energy Rating (BER) calculated?
A Building Energy Rating (BER) is based on the estimated carbon dioxide emitted by annual energy usage in that building. A BER assessor estimates the heat produced by appliances and sunlight through windows and the heat lost through the walls, floors and roof. Based on the size of the building, the number of occupants and the efficiency of the heating system, a BER is determined by how much heat is required to keep the building warm and the water hot.