E.ON has launched a new product to assess properties' energy efficiency.
The energy supplier has developed an 'energy fit insulation stick' to measure a home's insulation level.
Findings may encourage owners to undertake DIY projects to install roof and cavity wall insulation, thereby reducing their carbon footprint and saving money on heating.
Kevin Bryant, E.ON's Energy Fit instructor, said: "We want to help people get energy fit and hope our insulation stick will be a really simple to use tool to help people who don't know if they've got cavity walls, if they have been filled previously or how much loft insulation they might need.
"After all, making sure your home is well insulated is the single most important thing you can do to improve your energy fitness."
Research from the energy providers shows that 51 per cent of Britons don't know if they have cavity walls and more than three-quarters have no idea about loft insulation.