Question 1

How much does home insulation cost in the UK?

Accepted Answer

Costs vary by type: loft insulation runs £400–£800 for a typical house, cavity wall insulation £450–£1,500, and solid wall insulation £8,000–£18,000. Loft insulation is often DIY-able, making it the cheapest upgrade. Cavity wall and loft insulation are frequently covered by grants like ECO4 and GBIS.

Question 2

Can I get free insulation?

Accepted Answer

Yes, if you qualify. The ECO4 scheme covers up to 100% of insulation costs for households on qualifying benefits with an EPC of D or below. The Great British Insulation Scheme (GBIS) covers homes in council tax bands A–D in England (A–E in Scotland and Wales). Contact your energy supplier or local authority to check eligibility.

Question 3

What type of insulation is best for my home?

Accepted Answer

It depends on your house. Start with loft insulation (cheapest, biggest impact per pound). If you have cavity walls (most homes built 1930s–1990s), get them filled next. For pre-1930s homes with solid walls, internal or external wall insulation is the main option but it's expensive. Floor insulation and draught-proofing are good supplementary measures.

Question 4

Should I insulate before getting a heat pump?

Accepted Answer

Yes — it's one of the most important things you can do. Better insulation means less heat loss, which means you need a smaller (cheaper) heat pump that costs less to run. A well-insulated home might need a 6–8kW heat pump instead of a 12–14kW one, saving thousands on installation and hundreds per year on running costs.

Question 5

How much can I save on energy bills with insulation?

Accepted Answer

Typical annual savings: loft insulation saves £150–£250, cavity wall insulation saves £150–£300, solid wall insulation saves £300–£500, and draught-proofing saves £30–£60. Combined, a full insulation upgrade can cut heating bills by 30–50%. These figures are based on current gas prices and an averagely heated UK home.

Question 6

Is cavity wall insulation worth it?

Accepted Answer

Almost always, yes. It costs £450–£1,500 for a typical house and saves £150–£300 per year, giving a payback of 2–5 years. It's one of the fastest-paying home upgrades available. The main exception is if your walls are exposed to heavy driving rain, where cavity fill can sometimes cause damp — get a survey first if you're in an exposed location.

Question 7

How thick should my loft insulation be?

Accepted Answer

The recommended depth is 270mm (about 10.5 inches). Most UK homes have some loft insulation but not enough — a common setup is 100mm between the joists. Topping up to 270mm with a second layer laid across the joists costs £400–£600 and is a straightforward DIY job.

Question 8

Does insulation improve my EPC rating?

Accepted Answer

Yes, significantly. Adding cavity wall insulation can improve your EPC by 1–2 bands (e.g., D to C or C to B). Loft insulation alone typically adds 5–10 EPC points. A better EPC rating is required for the Boiler Upgrade Scheme grant and will be required for rental properties (EPC C from 2028 for new tenancies).

Home Insulation: The Complete UK Guide

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Cavity Wall Insulation: Costs, Grants & Is It Worth It?

Loft Insulation Guide: How Much Does It Cost and Save?

Should I Insulate Before Getting a Heat Pump?

Best Loft Insulation UK 2026: Materials, Thickness & DIY Guide

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