What is the best insulation for windows?
Even though the sun is still shining, I can feel a definite chill in the air, with the season changing. At this time of year, we always start thinking about how to make our homes warm for the winter.
We love Consumer NZ for their testing they do different products, and an article I came across recently compared different window treatments.
According to their website, the best option for insulating your windows (apart from double glazing) is installing Honeycomb blinds.
Honeycomb Blinds
These are a great economical option and work well in small, tight spaces. The translucent version offers some insulation while still allowing light through, with an R-Value of 0.31. The blockout version performs slightly better at 0.5—similar to aluminium double glazing. This is the only product we carry with a tested R-Value, simply because it’s easier to measure.
That said, they don’t offer the same warm, cosy feeling you might crave during a blustery Wellington southerly. They’re made from crude oil–based polyester; while the translucent version is recyclable at the end of its life, the blockout version currently isn’t.
Roman Blinds
Roman Blinds may be the next best option on the Consumer NZ list, if they are well fitted. However, bare in mind, not all windows will allow a blind to be closely fitted.
Well fitted Curtains
Next on the list (if you’re also keen on aesthetics) is heavy, lined curtains to the floor. This is what we specialise in. We avoid sill-length or shorter curtains because, aside from their reduced insulation, they simply don’t look as good.
Long curtains have a timeless elegance. I used to say that short curtains were like wearing trousers that are just a bit too short — but since cropped pants are currently in vogue, that argument doesn’t hold quite as well! Still, unless you’re after a cottage look, let’s be clear: short curtains are not in vogue. And it is obvious from the Consumer NZ study that to the floor is can retain an extra 5% of heat this way.
We create curtains that either gently skim the floor or pool slightly on the floor. This creates a good seal, trapping warm air inside. Warm air rises and will escape out the window under short curtains, while cool air from outside drops into the room. Floor-length curtains also make a big difference in older homes where walls aren’t insulated.
We often use a three-layer system of fabric and linings to further insulate windows — particularly important for single-glazed homes. You can read more about our curtains here.
What hasn't been disclosed in the Consumer NZ study, is how far above the window the curtains have been installed. As a "cheap hack" a rolled up towel was used to provide more warmth. It performed better than a standard thermal curtain, but who really wants a rolled up towel on top of your rod? We always try to strike a balance between aesthetics and performance. its the whole Form follows Function design rule. The best design is created when you win on both. We install curtains high above the window and sometimes even to the ceiling if it doesn't look ridculous. Overall we still think curtains that are well fitted are the best option.
Here is a link to the Consumer NZ Website for further details on their testing and resutls.
https://www.consumer.org.nz/articles/curtains
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