The biggest rating gains usually come from fabric, heating, and evidence quality, not guesswork. This page focuses on the practical moves that actually matter.
Loft insulation, wall insulation, and glazing upgrades are often where the rating changes most. The problem is not just the upgrade itself. It is whether the assessor can support it with evidence.
Heating controls, more efficient systems, and properly documented low-carbon upgrades can all help. The bigger point is that the system details need to be clear and attributable.
Low-energy lighting and obvious low-friction improvements are not usually the whole answer, but they can still help when the rest of the fabric and heating record is already strong.