Sunday, 12 January 2014

Energy saving 2

It's been nearly a month since I posted the first part of my energy savings series, and in the UK we are still waiting for winter to hit. This morning was the first hard frost we have had round my way, as you will see from the photos later on.
This is my loft hatch insulation as described in Energy saving no.1: Insulating the loft hatch. It is not a tight fit and I could probably do with some draught proofing around the edges of the loft hatch, but I will come back to that in a later post.

I am still going to focus on heat loss for this post, but I want to know where my heat is being lost. My loft space has a snug 'duvet' of insulation over it to keep the heat in. My brick walls have a cavity, which has been filled with insulation (though many years ago). My windows and doors are double-glazed. So where is the heat being lost?

Energy saving no.3: Thermal images to find where the heat escapes
For years I have wanted to have thermal images taken of our home. You have probably seen thermal images on the telly, in the police programmes where the helicopter crew can locate a suspect hiding in bushes by his body heat. Thermal cameras take an image of the heat, so on a cold, winters night when you have the heating on inside, a thermal camera can show where heat is leaking from your home. It can reveal a hidden picture of the ‘health’ of your home, showing where there are draughts or where more insulation is needed.

I put a request out through the Transition Town Group and Karl responded. He kindly offered to bring a thermal imaging camera round to try. It took us a while to get the hang of it, as neither of us had used one before. (The camera Karl borrowed is used by vets to detect the heat of infections in animals - isn't that amazing!) Ideally you should do this on a cold evening, but it was actually quite mild, so I turned the heating up high to give a bigger temperature difference between inside and outside. The thermal images aren't very clear, so I have taken some images of my home in daylight, so that you can see what they are showing.

The blue areas show lower temperatures, which means that less heat is being lost through these areas, such as the low sloping roof and much of the brick walls. The target sign on the thermal image gives a temperature reading written in the top left corner, so at that light blue section of the wall the temperature is 6.5 degrees celsius. I didn't measure the outside temperature, but I would guess it was 3 to 5 degrees. The yellow and green areas are warmer, showing more heat loss, and the red and white areas are the hottest, showing the greatest heat loss. These are the areas for me to focus on.

The thermal image shows that the downstairs bay window of my living room, is losing less heat than the bedroom window above. At the time the bay window had the curtains drawn, whereas the curtains for the bedroom were only partially drawn with a large gap in the middle. Could this be why there is a difference in temperature? There is also a radiator below the bedroom window, which may be why this patch of wall is yellow, rather than blue. The bright red area lower down the image is the glazed arch in our front door. The images below take a closer look at the front door.

Look at the bright red areas where the glass panels are and also the door handle. They were a bit of a surprise to me, as it is supposed to be an insulated door. I could really reduce heat loss by putting a thick curtain up behind this door. The area below the sill is also letting heat out as shown below.

This area is just below the floor level, so how can this area be warm? Maybe it hasn't been sealed properly below the door, or there are cracks or gaps where the air can flow through. I need to do some more investigation work here.

Here are the last two windows at the front of the house.
I was surprised by how dark the sloping roof is. There is no access to this sloping roof area, so it can only have a minimum amount of insulation from when it was built, if any. I think that had we been able to take an image from above it may not have looked quite so insulated.

The windows however stand out as being very warm. The upstairs window has lined curtains, which were closed and tucked behind the radiator, although the small top window was actually slightly open. Even with the window open, the heat loss from this window is a lot less than that from the window below, which has venetian blinds.

The way to reduce heat loss from windows does seem to be to have thick, lined curtains and to make sure that they are closed properly - with no gaps. I am going to make improving my curtains as another energy saving measure, but for now I am making sure that I close them properly. I can test how effective they are by going outside at night and seeing how much light shines through - if the light gets through, then the heat will too!

I do have one small window that is single glazed. It is tucked away in a narrow corridor between the kitchen and the garage, so it is sheltered.

The temperature of this window is 13 degrees C and it is glowing white! (We set the temperature band between 5 and 10 degrees, so in effect it is off the scale as it is 13 degrees C.)This room is a small downstairs toilet, which doesn't have a radiator, so tends to be quite cold. Although it is sheltered from the elements there is still a lot of heat lost through it (no wonder the room is cold!).

It is very interesting to see that the wall to the right of the pipe also shows as glowing white. Look at the position of the pipe. The photo shows that it is brick wall behind the pipe and to the right of it. Why isn't this blue/green/yellow like the rest of the walls?

We took many more images and I will use some in future posts, but I hope they have given an idea of where you could be losing heat in your homes.

If you want to get some thermal images of your property then you could try contacting your local council, the energy efficiency advice centre, the rural community council or transition town groups in your area to see if they can help. You are more likely to get someone to do it for free if you can get other people on your street or in your village interested. For instance Appleby Magna village had thermal images taken of all the houses in the village. They put the images on display in the town hall so that everyone could see their house and compare it to their neighbours. This gave them a good opportunity to inform people on insulating their homes and talk about any grants available.

There are other simple ways to locate where heat is being lost and this morning's frost was a perfect opportunity to check out your roof.

To get a rough idea of how much heat you are losing through your roof, it is important to get out early before the sun is high. Try to compare your roof with others that face the same direction. If you have a garage then use it to compare with. If no heat is being lost through the roof of your home then it would have as much frost on it as your unheated garage does.

I was right about that low pitched roof needing more insulation. It may be better insulated than the windows, but it as not as well insulted as our main roof. Below is the back of our house for a comparison. 
I hope this has been helpful and let me know if you have any questions J


  1. What a good idea to look at your roof on a frosty morning. Brilliant. Will try to remember in winter. We put double blinds and curtains on most of our windows last year, which has markedly reduced draughts, even from some of our old leaky windows. It's fascinating to see where the heat leaks out of the house. The windows are clearly the weakest link.

    1. Thanks Jo. Sounds like you are way ahead of me on the curtain front. Having double glazed windows lulled me into thinking they were more insulated, as you don't really feel a draught from them. I need to get sewing!

  2. Hi Judy,
    This blog is an absolutely fantastic example of how important it is to draft proof the doors and curtain all windows.
    Thank you so much for this. You will certainly make a big difference to my housekeeping now. I do plan have venetian blinds behind double glazed windows in a bathroom.. I suspect I will now make and put curtains over the windows as well.


    1. Thanks Suella. It is amazing to see the thermal images and where the heat is ebbing out. I am going to make some curtains too, but I was going to try making a Canadian 'window quilt' for the bathroom. It just adds a layer of wadding and a waterproof layer between the curtain material and liner. Then you have velcro to fix it to the wall, so there are no gaps for air to seep through. There are instructions online, but we did talk about having a transition workshop for making them, which would be more fun!

  3. Really good post! Hope there will be more good post here!Thanks for sharing valuable power