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Cunning practical ways curtains & blinds can keep you warmer and save you money

The headlines

Using curtains or blinds in the right ways in the right places can make a significant difference to how quickly your home will warm up, how warm it gets, and how much money you spend on energy.

Below are lots of simple practical ideas on where they can help and how to use them in a wide range of situations.


First some background about radiators under windows

Why radiators are often put under windows

Putting radiators under windows is far from ideal from an energy efficiency point of view. As a nation, we have put them there typically because:

  1. Householders didn't want them on internal walls where they might want to put furniture, and

  2. For many years, centrally heated homes only had single glazing making the window side of the room much colder. The logic was that radiators were put under windows to compensate for this "cold side". The need for this is much less with good double glazing.

Even with the latest double glazing though, windows are usually the leakiest parts of homes. This is actually the reason that most new homes have windows that are so much smaller than older homes.

The job of a radiator

The job of a radiator is to get the heat efficiently and quickly INTO the room and to warm YOU. In the animation below, you can how easily it flows up the wall before it circulates overhead into the room.

Picture source Siemens

As you can see in the image below, when radiators are put directly under a window, the warm air rising from the radiator gets interfered with and slowed down.

A lot of the air rising up from the radiator gets drawn towards the glass, warming it up, losing heat through to outside wasting you money. This will even be the case if you have modern double glazing.

Picture source Siemens

This means there is less warmth in the air is left over to heat the room. The warm air doesn't flow as easily or quickly into the room as it would do if the radiator was on an internal wall. The room will therefore take longer to warm up.

A curtain can really help with this, preventing much of the heat lost through the glazing if used in the right way.

The ideal thing to do is tuck your curtains behind the radiator as shown on the right in this photo.

The above tip is even more important to do if you have boxed in pelmets above your curtains.

Full length curtains in front of radiators are even worse. Most of the heat will end up going through the glass to the outside world!

If you can't actually tuck your curtains in behind your radiator do this if you can. It might not look pretty, but it'll immediately make you warmer and definitely save you money.

Picture from a Facebook post by Colin B (thanks!)

Thermal and lined curtains

Thicker fluffier or thermal curtain fabric will be better at keeping heat in than thin fabric for curtains.

What will make the BIGGEST difference though is having curtains that are lined, rather than a curtain that is just a single layer.

A lined curtain means you have two layers preventing heat loss. More importantly, a layer of air becomes trapped between the curtain fabric and the liner.

Air is a very good insulator so lined curtains are far better than ANY single layer curtain.


Let the sun help you when it is around, but close them when it isn't

Even if it is not that warm outside, direct sun flooding into a home will be heating the air indoors, even early in the morning.

Leave curtains open on sunny winter days to let the sun in. As soon as the sun has gone, keep curtains closed if it is practical. We leave most of our curtains closed in winter, even during the daytime, and always 24/7 in rooms we don't use much. The neighbours probably think we are odd...


Other window warmth barriers

Conventional blinds

Blinds help similarly to curtains, creating another barrier between the room and the glass.

Curtains AND blinds here in this photo below from Anne on Facebook. This will give double the benefit when both are closed as it will mean there are two layers of trapped air between the room and the glass for heat to get past.

This next one isn't a blind or a curtain but is effectively temporary secondary glazing. A really simple idea, with a plastic film and self adhesive velcro. It is only £15.99 or so from Amazon here.

The disadvantage is that it doesn't make it so easy to ventilate a room, and if you've seen any of my other articles on damp and condensation you'll know that some background ventilation is incredibly important in a home to keep the air healthy.


Clever new designs of blinds

The video below is for an innovative crystal clear plastic roller blind.

It gives you all the benefits of a roller blind, acts as secondary double glazing at the same time, and is clear so you can see through it. It's also a reasonably easy DIY job to fit one.

The British company selling this can be found here

The interior blinds below, known as honeycomb blinds are pretty clever also.

When the blind is lowered the blind forms lots of horizontal air pockets as you can see in the bottom right insert in the photo.

They are made to measure and are relatively inexpensive. They come in a wide range of colours from here. There is also a similar product from Ikea called a cellular blind, which you can find an example of here.

Simpler ideas for windows

Net curtains will make a small but useful difference, as anything that acts as a barrier between the room and the glass will help keep heat in.

Bubble pack is naturally full of air pockets which will all act as pockets of insulation. I don't know how effective it is as Ully on Facebook who posted this figure didn't comment, but it every little helps a long as you don't mind obscuring the view.

Below are some comments from Lee from Facebook about how much effect bubble pack had for him:

This next one is not for everyone but it would certainly make a difference. It is actually a first aid survival blanket, costing under a fiver from Amazon.


Curtain pelmets help

Not everyone likes them but they do help save energy, as the diagram further down shows.

I have seen one claim that they can reduce heat loss by up 15% but I don't know where this figure came from. Given that windows are so leaky from a heat point of view I suspect that could be right in some circumstances.

Pelmets make it harder for the air in the room to reach the window, and so help keep heat in.

If you want to make your own pelmets this web page has a step by step guide but there are plenty of others on Youtube.

You don't need a full box pelmet like those above though.

Even just using a simple horizontal piece of wood or plastic mounted above the curtain will help. The short video below from the Australian company Ecomaster explains a little more about why pelmets help. At the end of the video you get a glimpse of their simple product, which is very simple and might be something you could make or improvise yourself.

As mentioned in the video, pelmets are also good at helping reduce overheating in a home in summer.


If you don't have a curtain - improvise

This great picture from Abbey on Facebook. Any old blanket or sheet will do, and this is tucked behind the radiator too.


Improve comfort sitting near a window

If you work from home or regularly sit next to a window or patio door, drawing the curtain next to you will make you feel warmer and keep the heat in.

If it means you need to put a light on this is still probably the cheapest thing to do.

An LED light bulb only costs around a penny for 6 or 7 hours of light so unless you really want natural daylight the cost of running the light bulb will almost certainly be less than the amount of money you will save by keeping the heat in with the curtain. You'll certainly feel a little warmer.


Curtains between adjoining rooms or areas

If you have adjoining rooms or parts of the house that don't have an actual door between a curtain is a cheap and easy solution. Isolating one room or area from another will allow you to keep one room warmer than another (if that suits your situation), and save you money.

An ordinary full length curtain between the two is one option such as in this photo from Mimi on Facebook, creating two zones.

Another success story here from Tina on Facebook

There are also magnetic flexible "doors" which come in all sorts of styles. This one is from Amazon and is only around £25, but there are cheaper ones too. Just use the search terms "magnetic curtain" on the Amazon site.

This one is fitted in the kitchen of Nikki on Facebook with some comments from her about how good she found it.

This short video shows you just how easy they are to fit and how easy it is to walk through one. Jolly clever stuff.


Curtains in front of open stairs

If you have an open plan room downstairs with a stairway leading from it, keeping the downstairs room warm is very difficult. Warmth from downstairs will naturally want to rise to upstairs and cool air will come down to replace it.

Many people use a curtain like this, and swear by how much difference it makes. This is another photo from Colin from Facebook.


Curtains in front of exterior doors

Exterior doors aren't actually very thick or well insulated and can really benefit from a little help.

Curtains in front of doors like this are always described by people on social media a making a big difference.

Again, if the curtains are lined it gives the best result, as you end up with two layers of air as a barrier 1) between the two layers of the curtain, and 2) between the curtain and the door.

Thanks to Becka on Facebook for this

If you have a very draughty front door though a curtain will only make a modest difference. All UPVC doors (no matter how old) should be draught free.

Don't rush to replace them though if they are draughty. There are always things that can be done to fix UPVC door draughts (such as door adjustments, replacing seals, or using appropriate draught proofing products). Don't forget the letter box needs to draught free too.

Wooden doors are harder to draught proof but can usually be significantly improved.


If you have a room opening directly onto a conservatory

Some homes have a conservatory permanently connected to a room in the house as shown in the photo below. Keeping the internal room warm will be challenging and costly as conservatories are incredibly poorly insulated.

A curtain between the two areas would be very helpful at reducing warmth escaping into the conservatory.


The window tips above may increase condensation on a window (but don't panic!)

Anything you do to keep warmth away from your window glazing will increase the chances of condensation forming or increasing if you already have it. This is because the surface of the glass will be colder than it would have otherwise been. This will make it more attractive to moisture held in the air in the home.

Condensation is a sign that there is too much moisture created indoors for the amount of ventilation your room or home has. I have many other articles on the site on this subject, explaining more about why this happens and what you can do to reduce or eliminate it.

If you DO get more window condensation as a result of the above tips, then in a quirky way this is actually good news. It means that this water has formed condensation on your window glass and NOT somewhere out of sight in your home where it might cause much more serious issues.

Condensation on glass is annoying but it is the least harmful place for it to form. It is very hard for bugs or mould to grow on glass.

So what to do?

If you've read my other articles on this subject you'll know that simply leaving this moisture to dry off or putting the heating on to prevent occuring doesn't make sense.

The best and simplest solution is to get rid of this unwanted moisture when you find it, and get it completely out of the home either by:

  • using a cloth and squeeze the water out of the cloth down the drain

  • using a kitchen paper towel and disposing of it down the loo

  • using a window vac (they start at around £20) as they do a fabulous job in this situation

This might seem a pain to do but is a small price to pay for the energy you will have saved and the improvement in comfort you will have from trying some of the tips in this article.

The other way to prevent this from happening is to read my other articles on this subject for better approaches. The first of the specific articles on damp and condensation is here.

Feel free to drop me a line if you have any questions.


Finally, some history

The photo below is of an 18th century bed. Curtains were used widely for centuries in the UK to keep body heat in when sleeping as indoor temperatures were far lower than today in winter.


I run this website as a hobby, because I care about this stuff, and do it for no commercial purpose. If you have valued what you've seen, please tell other people about it.

All content on the site should be treated as information and not advice. You should take professional advice where appropriate to different site articles.


Mark Thompson

Get Energy Savvy - simple practical home energy efficiency information

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Nicola Bos
Nicola Bos
Oct 28, 2023

Thanks Mark! It's got us wondering about making a four poster bed frame and curtains - even good for daytime on cold days with just a little bit of electric blanket heat or hot water bottle, then body heat to maintain :)

Mark Thompson
Mark Thompson
Oct 28, 2023
Replying to

Do it!!!! :-)


Oct 28, 2023

Some great tips, thank you


Oct 27, 2023

Brilliant article thanks. Do you know if pelmets still do a good job if there is a radiator under the window?

Mark Thompson
Mark Thompson
Oct 28, 2023
Replying to

As long as you tuck the curtains in a pelmet will certainly be extra help if you have a radiator underneath. I’m fact if you have a pelmet it’s even more important to tuck the curtains in - if you don’t do that and the curtains are allowed to hang over the front of the radiator then the pelmet will help to trap the heat on the wrong side (the window side) of the curtain.


Oct 27, 2023

Superb article! 👍


Lisa Scott
Lisa Scott
Oct 27, 2023

Thanks Mark always great information as always, took away some ideas so thank you x

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