What is cavity wall insulation? How does it work? Can it save money on gas and electricity bills?
Simon Kelly from Dyson Energy Services, which carries out cavity wall insulations for energy firm E.ON, explains all in this handy video guide.
What's more, you could receive free insulation PLUS a £100 cheque from E.ON if you're in receipt of certain welfare benefits - and you don't even have to be an E.ON customer to qualify.
If you or anyone you know would benefit from free insulation and £100, you can check your eligibility and find out more about the offer here.