How can we check if our windows are energy-efficient (energy-efficient window check)

Energy-efficient glazing offers multiple benefits, as it increases the thermal insulation of the frame and is now installed in 99% of new frames manufactured. Energy-efficient glazing is divided into dozens of categories depending on its quality and characteristics (energy efficiency, light transmission, etc.). A widespread and quite reliable category of energy-efficient glazing is soft-coat Low-e energy-efficient glazing. In this article, we will examine how we can tell if our windows (glazing) are energy-efficient (energy-efficient window check).

An easy way to check if our windows are energy-efficient (energy-efficient glazing check) is to use a lighter. By lighting a lighter and bringing the flame close to the windows we want to check, we will notice two double reflections (one for each pane). See the example and the photos below.

Energy-Efficient Glazing

If the glazing is energy-efficient, we will see the two reflections have a slightly different shade. If we observe the flame in reflection No. 1, it is slightly bluer than the flame in reflection No. 2. This happens because the pane reflecting the flame in reflection No. 1 has a soft coating (Low-e energy-efficient glazing).

Simple double glazing

If the glazing is simple (not energy-efficient), the two reflections created (No. 1 and No. 2) have exactly the same shade (energy-efficient check).

-Another way (not entirely reliable) to determine if the glazing is energy-efficient is to look at the panes from the outside. Energy-efficient windows commonly used often act as mirrors (reflect), much more so than simple double glazing, due to their coatings.

-Another not-so-reliable way to check for energy efficiency is, on a warm and sunny day, to open our frame (window or balcony door) and place our hand in such a way that half of it is directly exposed to the sun and the other half is behind the pane being examined. Within 1 minute, if our pane is energy-efficient, there should be a different temperature at the two ends of the hand, which we will feel because the part of the hand directly exposed to the sun will ‘burn’ compared to the part behind the energy-efficient pane.

-The safest way to determine if our windows are energy-efficient is with an energy-efficient glazing detection device, which many professionals possess.

All the above tests were performed with soft-coat Low-e energy-efficient glazing (energy-efficient check) from Guardian (Climaguard solar), and there may be variations with other types of glazing.

See prices, types, and kinds of all energy-efficient windows

Alternatively, read how to tell if your frames – aluminum are energy-efficient (have thermal break)