Note: These are only indications from one test with empty boxes and will have to be tested a few more times to be confirmed. Boxes with live colonies of stingless bees will show different results as the brood will be insulated by the surrounding nest structures.
- Six empty 33mm thick hoop pine box painted white
- Temperature sensors inside the top of the box in the honey super.
- Boxes are placed in full sun from 10am and receive full sun until 2pm.
Photo above taken at 1pm. Note the roof overhang and shade on the box, from left to right:
- Small tin roof
- White cottage roof – 15mm thick pine
- Large PVC roof – 10mm pvc
- No roof
- Small PVC – 10mm pvc
- Foam cover white 30mm thick
Chart below: The boxes are 33mm and painted white. This provides some pretty good insulation from the sun. There’s only a few degrees between each box and roof.
There’s not much difference between the large pvc, small pvc and cottage roofs, even with a bit more sun on the side of the box. The box is white and reflects the heat so there’s not enough difference between these three roofs to be able to conclude any one roof is better than the other.
The Foam covered box painted white was the coolest. I’m not a fan of foam covers but the tests show it performs really well and I’d say it’s a significant difference compared to the standard roofs.
The tin roof appears to have added heat compared to the box with no roof at all. Keeping in mind that the sensor is in the top of the box and normally the brood area would be insulated by the honey super section anyway. In extreme temperatures in full sun the honey super could become warmer but may not have any significant effect on the brood area.
Don’t panic! Results will vary in different conditions and temperatures so don’t worry if you’re currently using a tin roof. The brood will be insulated by the honey super and nest structures and most hives aren’t kept in full sun anyway.
If the boxes were dark coloured hardwood then the sun on the side of the box may make more difference.
