Of all the home improvements you can make to cut energy bills, loft insulation consistently delivers among the highest returns for the lowest cost. The Energy Saving Trust estimates that a properly insulated loft can save a typical UK semi-detached home up to £300 per year on heating. If you have not checked yours recently, it is worth doing today.

Why Loft Insulation Works So Well

Heat rises. In an uninsulated home, a significant portion of the heat you pay to generate simply escapes through the roof. The recommended depth for mineral wool loft insulation is 270mm — the equivalent of about 27cm or roughly the length of a standard ruler. Many UK homes built before 1990 have either no insulation or insulation well below this depth, often just 100mm installed during the 1980s. If you want to cut your energy bills today, it only takes a few minutes.

The Cost of Installation in 2026

For a standard loft with accessible joists (no conversion, no boards), professional installation typically costs:

• Top-up from 100mm to 270mm: £300-£500 for a typical semi-detached
• Installation from scratch: £400-£700
• DIY top-up: £150-£250 in materials if you are comfortable working in a loft space

At those prices and with savings of £150-£300/year, payback periods of 1-3 years are realistic — making this one of the highest-returning home investments you can make. You can also energy saving advice to see what’s available.

Getting It Free Through ECO4

The government’s ECO4 scheme funds free energy efficiency upgrades for qualifying households. Loft insulation is one of the most commonly funded measures. You may qualify if you receive means-tested benefits (Universal Credit, Housing Benefit, ESA etc.) or if your home has an energy performance rating of D, E, F, or G. Check eligibility at gov.uk/ECO4 — the application takes about 10 minutes and could get you hundreds of pounds of work done at zero cost.

Practical Tips Before You Book

• Check your current insulation depth before calling anyone — a simple ruler measurement tells you whether you need a top-up
• Clear the loft hatch area and ensure safe access is possible before the installer arrives
• If your loft is boarded, you may need specialist advice — boarding over insulation compresses it and reduces effectiveness significantly
• Check whether your installer is TrustMark or Which? Trusted Trader registered

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