Technical terms explained
Energy Performance and Standards:
Retrofit - Upgrading an existing home to make it warmer, healthier, cheaper to run and more energy efficient. Examples include better insulation, new windows or improved ventilation.
Energy efficient - A home is considered energy efficient when it uses less energy to heat, cool or power everyday activities, meaning it stays warm more easily, wastes less heat, and costs less to run. Energy‑efficient homes often have better insulation, improved windows, efficient heating systems, solar panels and good ventilation, which together help lower energy bills and make the home more comfortable.
EPC (Energy Performance Certificate) – A national certificate that rates how energy‑efficient a home is. Homes are graded from A (most efficient) to G (least efficient). It helps show how much energy a home uses and how much it may cost to heat.
PAS 2030/2035 - Government‑approved standards that make sure all retrofit work is safe, high quality, and installed correctly. They set rules for how assessments, design and installation must be carried out.
Energy Survey / Retrofit Assessment - A detailed survey that checks how your home currently uses energy, what improvements it needs, and whether it is suitable for the programme.
Fabric-first approach - An approach where we first improve the building structure itself (walls, roof, windows, insulation) before adding new technologies like solar panels. This helps reduce heat loss and prevents damp and mould.
Building and Insulation:
Cavity Wall Insulation / Cavity Wall - Many homes have two layers of external walls with a gap (cavity) between them. Filling this gap with insulation helps keep heat in, reducing heating costs and improving comfort
Glazing / Double Glazing - Windows made with two layers of glass. This reduces draughts, cuts down on condensation, and helps reduce heat loss and outside noise.
Roof or Loft Insulation – Insulation added to the top of the home to keep heat inside. It helps top‑floor homes stay warmer in winter and cooler in summer. A lot of heat is lost through the roof of a home.
Ventilation - Systems such as fans that bring fresh air in and remove stale, damp or humid air. Good ventilation helps prevent condensation, damp and mould.
Damp and Mould - Damp happens when excess moisture builds up in the home. Mould is a fungus that grows in damp areas. Both can affect health and damage the home.
Air quality - A measure of how clean the air is inside a home. Good air quality means lower levels of moisture, carbon dioxide, pollutants and mould spores, helping make homes healthier to live in.
Energy Systems and Technologies:
Solar panels (photovoltaics) - Panels installed on the roof that convert sunlight into electricity. They help reduce electricity costs by generating clean, renewable energy.
Environmental sensors - Small devices that monitor things like temperature, humidity, damp, mould risk and air quality. They help spot problems early so action can be taken before issues get worse. Many councils are starting to install these on their council homes as part of basic health and safety measures.
Surveys and Safety Checks
Asbestos survey - A routine safety check carried out before work begins. It identifies any asbestos‑containing materials so that work can be done safely.
Cavity wall check - A check to see whether the cavity walls are suitable for insulation — for example, whether they are damaged, blocked or already filled. This is sometimes done during the energy survey stage
