Wall-mounted or ducted air conditioning: which should I choose?

The wall-mounted split is the default for good reasons: least cost, least disruption, no builder's work, and modern units have become genuinely discreet, slim, quiet and paintable-around. In a finished home it is almost always our recommendation, because the ducted alternative means opening ceilings that were not otherwise being touched.

Ducted systems hide the indoor machinery in a loft, ceiling void or joinery bulkhead and deliver air through slim grilles. The rooms show nothing on their walls, which matters in period interiors with cornicing, in minimalist schemes and to people who simply dislike visible units. The costs are the equipment, the design time and above all the builder's work of routes and access.

Timing is the real decision variable. Mid-refurbishment, with ceilings open and a builder on site, ducted's premium shrinks to its true hardware and design cost, and we work to the architect's drawings at first fix. In a finished house the same system carries thousands of pounds of making-good, which is why we often talk people out of it honestly.

There is a middle path worth knowing: one ducted zone for the space that justifies it (a new extension, a loft floor being built) and wall units elsewhere. Mixed systems are common in our London work and let each room get the right answer rather than one ideology.

More in choosing a system, or browse all 40 questions on the FAQ index.