Windows make up a good third of the facade. They define how much heat stays indoors, furthermore roughly 40% of the unwanted heat that builds up in your home comes in through windows. U-value is a measure of heat transfer/loss in a building element. Lower U-values indicate higher levels of thermal insulation which leads to greater thermal comfort and greater the savings in energy costs. To discuss high performance windows and doors, please contact us on 02 98171232