Bumblebees (Bombus hypnorum) in their nest in a bird box, … Flickr
Bumblebee Box size. For a single chambered box the minimum size is 15 x 15 x 15 cm, the largest size is 25 x 25 x 25 cm. Space between the box and the nest. Ventilation is very important. The brood will be kept at a temperature of above 30 o C regardless of the temperature outside, so there is a need to get rid of the condensation. Apart from.