Waitz Energy
Free Tool

Insulation ROI Calculator

Find out which insulation upgrades give you the best return on investment. Real UK costs, ranked by payback period, no sales pitch.

Your Property

Your current monthly spend on heating fuel

Current Insulation

Prices: Ofgem Q2 2026 cap. Gas 6.76p/kWh, electricity 24.50p/kWh, oil 5.89p/kWh, LPG 7.64p/kWh. Costs based on typical UK installer quotes 2024-2026.

Where Your Heat Escapes

Based on typical heat loss proportions for your property type and current insulation.
£3.2k
total cost
all upgrades
£580
saved per year
on heating bills
5.5
years payback
weighted avg

Upgrade Options (Ranked by ROI)

Cumulative Savings Over 10 Years

Year 1 Year 10
£5,800 saved over 10 years

The honest bit

  • - Real heat loss depends on construction details, exposure, and how you use your home. These are ballpark figures based on typical UK properties.
  • - Insulation order matters. Do fabric improvements first, then right-size your heating system. A heat pump in a leaky house is a waste of money.
  • - Older properties (especially solid walls) need care with moisture management. External wall insulation changes how damp moves through the wall.
  • - Internal wall insulation reduces room size by 60-100mm per wall. Worth it for savings, but factor it into your decision.
  • - A proper thermal imaging survey (£200-400) shows exactly where heat escapes. A calculator cannot replace that.
  • - Grants may be available. Check GOV.UK for current schemes like ECO4 and the Great British Insulation Scheme.

Want to know exactly where your home loses heat?

A thermal imaging survey and retrofit assessment tells you precisely which upgrades will make the biggest difference. We cover Bedfordshire, Cambridgeshire, and Hertfordshire.

Book a Free Assessment

Related reading

Heat Pump Savings Calculator Heat Pumps: What the Tabloids Won't Tell You Who Pays for Energy Upgrades in UK Properties Thermal Imaging Surveys