Double Glazing v Triple Glazing

Double and triple-glazing side-by-sideTriple-glazing is often marketed as a better option than double-glazing. While it’s true that triple-glazing does offer some benefits, it may not be the best or most economic solution for you.

Triple-glazing is what enables window manufacturers to achieve U-values of 1.0 and better. But such U-values are really only of benefit where they fit into an overall energy saving build, such as in a low energy house or a passive house.  Where windows are being fitted into a standard build or as part of a refurbishment project then double-glazed units offering U-values as good as 1.1 are preferable. And other benefits such as noise-reduction and solar control can be included in double-glazing for less than the cost of a standard triple-glazed unit.

In Norway legislation is dictating that soon all new buildings will be triple-glazed but this is also in line with other regulations designed to improve the overall energy saving potential of buildings. Until such time that the UK building industry is forced to greatly improve energy efficiency of new build homes then there will be no realistic requirement for triple-glazing to be fitted as standard.

In conclusion

If considering triple-glazing, the following sums up reasons for and against choosing triple-glazing:


  • Triple-glazing often = low U-values suited to low-energy and passive house projects.
  • Triple-glazing will return the value of your investment when fitted as part of correctly specified low-energy or passive house project.
  • Further upgrades to glazing material can achieve superior noise reduction compared to double glazing.


  • Generally higher cost.
  • Reduced light penetration due to additional layer of glass.
  • Contrary to popular belief, triple glazing does not reduce noise any more than standard double glazing.
  • Overall greater weight than a double glazed unit could pose a problem for your project.
  • Triple-glazed units can suffer from a phenomena of occasional condensation on the outside pane due to low transfer of heat from the inside to the outside which allows moist air to condense onto the cold surface. A rare occurrence but one that surprises people.



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Broxwood’s passive house standard timber windows and doors provided the perfect solution for Findhorn’s ecovillage development. Read the Findhorn case study