Double glazing

​All properties lose up to 10% of heat through windows. Energy-efficient glazing can keep your home warmer and quieter as well as reducing your energy bills. That might mean double, triple-glazing or secondary glazing.

Benefits of energy-efficient windows

  • Smaller energy bills.
  • Smaller carbon footprint.
  • More comfortable home: energy-efficient glazing reduces heat loss through windows and means fewer draughts and cold spots.
  • Peace and quiet: as well as keeping the heat in, energy efficient-windows insulate your home against external noise.
  • Reduced condensation: energy-efficient glazing reduces condensation build-up on the inside of windows, however replacement windows will be more airtight than your original frames, so condensation may build up due to the reduced ventilation. If your house does not have much background ventilation, look for replacement windows with trickle vents incorporated into the frame to let in a controlled amount of air.
  • More secure than single paned windows.

Diagram showing triple glazing.

Savings when double glazing is installed

​The costs and savings for energy-efficient glazing will be different for each home and each window, depending on its size, material and the installer you choose. Double glazing should last for 20 years or more and over that time the savings shown could more than pay for the cost of the initial installation.

Window energy rating​Detached houseSemi-detached houseMid-terrace houseBungalowFlat
​A rated£120 - £160£85 - £110£65 - £90£55 - £75£40 - £60
B rated£110 - £145£75 - £100£60 - £80£50 - £70£40 - £55
C rated​£110 - £135​£75 - £95​£60 - £75£50 - £65​£40 - £50

These savings are per year for a typical gas-heated home.