Heat pump Cover size is determined by the four measurements described below. These are to be taken as tight measurements (without allowances for error or a bit extra for safety's sake).
There is an allowance built in between the maximum measurements described for each size and the best fit cover specified for your unit.
Taken from the ground (or where bottom of cover is intended to be) to the top of the outdoor unit.
Measured across the widest points of the unit. This does not include parts on the wall that are behind the unit and will fit in the gap between the cover and the wall. E.g. Isolator switch or pipework.
The 'box' part of the outdoor unit not including mounting feet
Measured from rear of heat pump unit to front most point inclusive of mounting feet.