The outdoor unit, and the cylinder up the stairs
Two objects, two different worries. One lives against the house, the other has to get round the turn on the landing.
Choose a size
Drag to walk round it
Opens your camera. Point it at the ground.
Once it appears: one finger drags it, two fingers turn it. It does not need a clear floor. Drop it where it fits and judge the size against what is already there.
Clearances outside, access inside
An air source unit needs air. A cylinder needs a staircase that turns. Both get measured before anything is ordered.
Let them scan it and hold their own phone up
The camera view only works on a phone. Point the code at their camera, and this page opens on their handset. That is the moment the idea sells itself.
Clearances shown are typical and must be checked against the specific unit's installation manual. Noise assessment for air source heat pumps follows MCS 020 and is measured at the nearest neighbouring habitable room window. Heat pump sizing requires a room by room heat loss calculation. Unvented cylinders must be installed by a G3 qualified person.