Thermal performance of curtains and roman blinds

Do you remember back to the heat wave in July 2022?  The advice was to keep your curtains closed to avoid your home overheating. Whilst it only lasted a few days in Scotland it did get me thinking, is the opposite true?  If curtains keep the heat out in summer, can they keep the heat in during the winter?

Personally, I know this is true.  A few years ago, we build a beautiful glass extension.  We have good quality windows but a lot of glass! Last winter when I came down in the morning and opened the curtains, I could feel the cooler air trapped between the curtain and the window.  The curtains were providing an additional layer of thermal insulation.  Our curtains are fitted floor to ceiling so there are limited gaps around the recess. They are made of 100% wool – a wonderful, natural product that we undervalue in the UK.  As well as its natural beauty wool is thermally efficient, naturally fire retardant and incredibly tactile.

Whilst I know my curtains help keep the house warmer, I wanted some scientific evidence so started doing some research.  A study was done in 2017 by Salford university.  The full details are available here. There are numerous scenarios tested however the general results indicate a 15-17% reduction in heat loss if your curtains are closed by dusk.  The figure for blinds is slightly lower at 13-14%.  These are significant efficiencies given the current exorbitant fuel prices.  It may also be possible to enhance these savings by following a few further top tips.

Maximise the thermal performance of your curtains and roman blinds

Face fabric – clearly the denser and thicker a fabric the more likely it is to be thermally beneficial.  Data is not published on a fabric-by-fabric basis but we all know that a wool blanket will keep you warmer than a light weight polyester one.  If keeping the chill out is a primary concern opt for a heavier weight fabric.

Lining – Our 260g blackout lining is one of the densest linings available.  It is primarily designed to keep the light out but the 3 pass (or layers) also make it very thermally efficient. Add an interlining  and you will further enhance the thermal performance of your curtains.

We would love every customer who wants interlined curtains to have them, but we are also realistic and appreciate that they are expensive (due to the additional materials and hand sewing involved).  We have therefore bought an additional duolining into our lining collection.  This lining is very soft and combines a poly cotton lining with a fleece layer.  It will therefore add body and warmth to your curtains and is a good compromise between lining and interlining. For roman blinds we would use our bonded blackout lining to minimise heat loss.

Hanging – reducing gaps around your curtains/blinds will result in less space for that cool air to creep into your home. Consider hanging floor to ceiling, adding a pelmet or choosing a track that keeps the curtains as close to the wall as possible. Some customers may also choose to fix the edge of their curtains to the wall. Whilst this may not enhance the way the curtains hang we understand that extreme situations call for extreme measures!

During the winter, open curtains during the day to make use of the heat of the sun, particularly on west and south sides of a building. Opening curtains could also reduce the build-up of moisture from condensation on your windows. When the heating goes on and the sun sets, close them to trap the warm air inside.

We are also hanging a stair curtain this winter.  We love our open plan living but with high energy costs I want to keep the kitchen as cosy as possible and prevent the heat (and ££) from dispersing around the house! The stair curtain will be double sided with a concealed 6inch pencil pleat tape at the top. The curtain will be hanging on a ceiling mounted curtain track from silent gliss so there are no gaps!

I hope you manage to stay warm this winter.  In the middle of winter, in Scotland, I do admit to not opening my curtains all week whilst the family is at work and school! I then really appreciate the view at the weekend!