We have recently borrowed a Thermal Imaging camera from The Green Valleys, ostensibly to check on the insulation properties of the house (and others in the valley), but it was interesting to turn the lens on one of the compost heaps. (It’s also very useful for finding black cats on moonless nights!)
This heap is the one currently being filled and so is ‘working’. As with all our heaps (7 in total) it is covered with black plastic, but also, underneath the black, is one of our compost bin lambs wool duvets. Although its pretty cold outside the heap is still working, and is full of worms munching away.
The first picture shows the thermal image of the top of the heap with plastic and duvet in place and the second the top of the composting material itself, quite a bit of which has only recently been added, so not up to temperature yet. The temperature at the centre of the photos is shown as a figure on the right hand side, the range of temperatures in the photo is on the scale on the right. 6C is approx 43F
The difference is quite remarkable, being around 12C (21F) hotter (the yellow and red areas) under the duvet than on top. 18C is approx 64F
And here is what a (slightly mucky) compost duvet looks like in real life, with the top black plastic cover pulled to one side. The filling is unwanted lambs wool shearings from a local farmer – very green! If you live local to us, I can supply a limited number for a small fee. Use the reply/ comment form at the bottom of the page to get more details The basic size is four foot square, although other smaller sizes are possible, as this is the bin size we find best suited to making good compost.