It makes sense to maximise your thermal insulation. Double glazing facilitates thermal insulation more so when combined with an inert gas and Low E glass
What is argon or krypton gas and Low E Glass?
Argon gas is a naturally occurring inert gas which is not harmful to you. By trapping a measured amount of Argon gas between the panes of glass and sealing it in, the insulating performance of your double glazing increases. Argon gas is roughly 40% denser than air and acts as a greater barrier to heat loss in the home, with a thermal performance increase at or around 15%. Low E Xtreme has the added option of krypton gas, also a naturally occurring inert gas. Krypton is twice as dense as argon further slowing down any thermal energy transmitting through a window.
Low E, or Low Emissivity glass, reflects long wave radiation thereby helping part of the heat inside the home. The level of retention is influenced by the Low E type, (Low E Plus, Low E Max, Low Xcel or Low E Xtreme). Using a combination of Low E glass and gas gives the best thermal insulation performance.
When the internal air temperature is 200C and the internal relative humidity is 69%, condensation will not form on double glazing with a U value lower than 2.40 W/m2k. Single glazing has a U Value of 5.7 while standard double glazing has an average U Value of 2.9 (Varies by spacer width) both of which would see condensation form on the inside of the windows in those conditions. The whole Metro Low E range has a lower U value than 2.40 W/m2k (all quoted numbers are at 12 mm spacer width).
The Metro Low E Double Glazing range comprises, Low E Plus, Low E Max, Low E Xcel, Low E Xtreme