Energy saving tips

How loft insulation affects your EPC

It's one of the cheapest improvements and one of the things I check first. Here's what to look for.

Heat rises, and in a house without enough loft insulation a lot of it goes straight out through the roof. Loft insulation is one of the cheapest improvements you can make, and it's one of the first things I look at during an EPC visit.

How much is enough?

The usual recommendation for a loft is around 270mm of mineral wool insulation, which is about 11 inches. Many older houses have much less: 50mm or 100mm laid decades ago, which has often been squashed down over the years.

How to check yours

1. Take a torch and a tape measure up to the loft hatch. Only go in if it's safe to stand on the joists or boards.
2. Look across the loft floor. If you can see the tops of the wooden joists, the insulation is thinner than the joists are deep, which usually means there isn't enough.
3. Measure the depth in a couple of places, away from the hatch.
4. Check it covers the whole floor, right into the eaves, and that it hasn't been squashed under stored boxes.

What it means for your EPC

On the survey I record the insulation depth. If it's thin or missing, topping it up will usually appear as one of the first recommendations, because it costs little and makes a real difference to the rating.

A few cautions

• Don't block the gap at the eaves. Lofts need air flowing through to avoid condensation.
• If you board the loft for storage, raise the boards above the insulation rather than squashing it.
• If you're having it topped up, keep the receipt or paperwork. It helps me record it properly on your next EPC.

Declan Hughes, Domestic Energy Assessor · Mourneview EPC