Synergy uses one of the industries highest regarded window profiles to manufacture the windows we use. The windows are manufactured to British Standards and can last around 20 years. In addition to the expected life span of our windows we offer a 10 year warranty on the windows, a 5 year warranty on the sealed units and a 10 year workmanship warranty. This means you can buy with confidence and know that your windows are not only energy efficient but will last you years to come.