You can feel the effects of poor insulation — rooms that never quite warm up, draughts you can’t quite locate, a heating bill that seems high no matter what you do. But before you spend money on improvements, it’s worth knowing exactly where the problem is. Here’s how to assess your home’s insulation properly.

Get an Energy Performance Certificate (EPC)

If you don’t already have one, an EPC is the most straightforward starting point. It gives your home a rating from A (most efficient) to G (least efficient) and includes specific recommendations for the improvements that would have the greatest impact, along with estimated costs and savings.

An EPC assessment costs £60–120 and takes about an hour. You can find accredited assessors through the government’s Find an Energy Certificate service. If you’ve bought or rented in the last decade, you may already have one — they’re valid for 10 years.

Check the Loft

Take a look in your loft. The current recommended depth for loft insulation is 270mm (about 10 inches). If you have less than this — or nothing at all — you’re losing significant heat through the roof. Heat rises, so an uninsulated or under-insulated loft is one of the most expensive problems a home can have.

Topping up loft insulation is straightforward and relatively inexpensive (£300–600 for a professional installation). It’s also one of the highest-ROI home improvements available.

Check for Cavity Walls

Most homes built in the UK after about 1920 have cavity walls — two layers of brick with a gap between them. This cavity can be filled with insulation, but many properties haven’t had this done.

You can check whether your walls are solid or cavity by looking at the pattern of the brickwork. Solid walls typically have alternating long and short bricks on each row. Cavity walls usually show only the long face of bricks in each row. If you have cavity walls, drill a small hole in an inconspicuous spot and poke a skewer in — if you hit a gap, it’s a cavity; if it goes straight into insulation or solid material, it may already be filled.

The Thermal Imaging Option

Thermal imaging cameras (available to rent from tool hire companies for around £40–60 per day, or some councils offer free surveys) show heat loss visually. Cold spots on walls, gaps around windows, and uninsulated areas show up clearly. This is particularly useful for identifying where draught-proofing would have the most impact.

Signs of Poor Insulation in Day-to-Day Life

• Rooms that cool down quickly when heating is turned off
• Walls that feel cold to the touch on the inside
• Visible condensation on interior walls (indicates cold surfaces)
• A noticeably warmer upstairs than downstairs (heat escaping through the roof)
• High heating bills relative to similar-sized properties nearby

Free Surveys and Grants

Energy suppliers are required to offer energy efficiency improvements to eligible households under the ECO4 scheme. This can include free insulation surveys and funded installation for qualifying properties. Contact your energy supplier or check the government’s Simple Energy Advice service to see what you might be eligible for.

Ready to cut your energy costs? Compare deals today and see how much you could save.