I have a new gadget… a thermal imaging camera!

Or the use of one I should say…

I hate being cold. I’m pretty “nesh” as they might describe me in these parts, or “frileuse” in my family…. So maybe it was accidentally on purpose that I fell into my job as a “comfort” engineer.

I might therefore be forgiven for my mission to provide as many people as possible with comfortable environments without it costing the earth. I may as well start at home. On loan from Transition Wilmslow – a local sustainability group I volunteer for – I used the thermal imaging camera to identify the cold spots in our newly acquired house.

Surfaces at different temperatures will emit infra-red radiation at different rates, which is what the thermal imaging camera detects and relays using a colour spectrum. Therefore, in my chosen scale*, cooler surfaces will be in the purpley-blues, warmer surfaces in the yellow-orangey-pink hues. 

On a cold day then, a well-insulated, airtight building will appear practically uniformly blue on the outside (surfaces approaching outdoor temperature), and uniformly yellow-orange on the inside (surfaces approaching internal heated temperature) – note that lights and other emitters of heat will skew the spectrum of what is being viewed.

A poorly insulated, thermal bridge-riddled wall will have clear lines, junctions or patches of purple-blue when viewed from the inside, yellow-red from the outside, showing that heat is bypassing the insulated part and escaping to outside. Similarly with draughts, cold air around door and window frames will cool the surfaces and show up blue.

Why use a thermal imaging camera? Sometimes we don’t want to stare a problem in the face. We can have an inkling that we should better wrap up our houses, but it’s not until the picture is painted for you that you really see the scale of the problem. And temperature is so subjective, we learn to live with the discomfort, and accept that some people will always be less comfortable than others. Those who are financially secure will compensate by paying higher heating bills, as they always have done, and possibly not even care. At the other extreme, some struggle to adequately heat their homes, facing the choice of fuel or food, which should be shocking to us all, and yet fuel poverty affected 11% of UK households in 2016.

Thermal imaging, without extensive number crunching and better accuracy won’t tell you a huge amount (numbers wise), but there is something about having it laid out in multi-colour that makes it much more tangible and it certainly has the potential to jolt us into action.

So here’s what I found out about my house, a block and brick construction with suspended floor, which we believe was built in 1978…

  • It may well have cavity insulation (but if it has, it’s minimal).
  • There are odd blue patches in some places, which appear (blue) on the inside but not (red) on the outside… a hole between blocks filled in with mortar but insulated on the other side?
  • The draughts are pretty shocking, even in the absence of an air tightness test.
  • We really have to get on and insulate the loft properly, including the hatch.
  • We need to do something about the single glazed windows on the south east elevation.
  • It would be great to insulate the floor – I just need to figure out how, given the associated disruption.

Ideally we would wrap the walls in wood fibre insulation and lime render – I will get a quote and start saving up!

Finally, curtains will help in our hallway and the French windows onto the garden. Although they don’t necessarily reduce the heat loss overall from your home (only delay it to when you have the heating off at night, say), they do deal with downdraught and radiated cold and so definitely help with comfort.

You can assess your own home using this type of camera. Why not book onto one of the free Carbon Coop’s thermography courses if you’re in the Greater Manchester area. Or I could do the survey for you if you are local, and work out an action plan. The imaging camera will highlight where the draughts are, or tell you if your cavity insulation has started to settle and cause air gaps for example. Your loft hatch may well be a weak point in your insulation. The corners and junctions are terrible thermal bridges, allowing heat to shortcut to outside… With only a few pounds you can apply low-tech solutions in the short term to some of these problems, while you plan a longer term retrofit.

As importantly, dealing with draughts and temperature asymmetry – where your body experiences differing radiant temperatures from surrounding surfaces – will ensure a healthier internal environment… and no more feeling that cold! (I was writing this with fingerless gloves and several layers of clothing despite the heating being on… And it’s not even freezing outside!)

Eventually you may decide you don’t want to live with it all and to cloak your whole house in a thick woolly layer, or invest in triple glazing as your next big step.

If it’s of interest you can map your improvements by going back through your energy consumption figures after various interventions. Nottingham City Council for example have received European funding and followed a Dutch energy efficiency retrofit scheme, and believe that with a £62k budget they have halved the energy consumption of the refurbished homes. An individual home EnerPHit level of certification (Passivhaus for retrofit) may cost you in the region of £100k. This is the long term investment end of the scale. It would be interesting to compare the measures here with the GMCA’s recently ratified Infrastructure Framework 2040, who believe their at-scale retrofit measures would only cost £31k on their portfolio to reduce emissions by 45%.

There is clearly a lot we all must do if we are to reduce our overall carbon emissions by 70% – I took the first step of documenting my problem using infra-red pictures, so why don’t you?


(c) 2019 Humbeblee