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WINDOWS - Plus Condensation & Moisture Management

Renewing old double glazed windows (pre 2006) or single glazing with modern double glazing will significantly reduce heat loss, instantly making your house feel much warmer. Old double glazing can be updgraded to Low Emissivity glass, keeping the existing frames for roughly 50% of the cost of new double glazing, so it's worth consideration.

The U values below reflect how quickly heat is lost through a window. The higher the number, the quicker the heat is lost. Vacuum glazing is a relatively new product and being very thin is ideally suited for upgrading single glazed windows in wooden frames.

Single Glazing – 5.6 u value
Standard Double or Single and secondary – 2.8 u value

Modern Low Emissivity Double Glazing – 1.2 u value

Triple or Vacuum glazing – 0.7 u value


Closing curtains, blinds or shutters at night can also reduce heat loss by up to 20%, particularly those with thermal linings. To choose the most energy efficient window, look for the British Fenestration Rating Council rating. If you installed A++ rated double glazed windows replacing single glazing, the savings could be up to £235 a year and 405kg of carbon dioxide.


Condensation and Moisture Management

If you have condensation in between the panes of glass in your double glazing units, then it is likely that the seal is broken, and the unit will need to be replaced – an ideal time to upgrade to Low Emissivity glass. If you are getting condensation on the outside of your windows, this is not a problem – it’s a sign that your windows are very efficient. Condensation on the inside of windows is difficult to avoid during winter, but there are several ways to manage it:

  • Clear up any condensation each morning to prevent mould occurring.

  • Avoid drying clothes on radiators and in the house as much as possible. If you have no choice, do it in one room like the bathroom, keeping the door

    shut and either open a window, or use a low energy dehumidifier.

  • Always use an extractor fan or open a window when cooking.

  • Monitor humidity levels with a humidistat (currently about £8 on Amazon).

    If the level exceeds 60%, then open the window and let some cooler and dryer air in.



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