Installation 10 · Milton Keynes · November 2026
Kitchen and landing, one outdoor unit
This two-storey house in Milton Keynes now has a Haier multi-split: one 5.5kW 3-port outdoor unit running a 3.5kW indoor unit in the kitchen downstairs and a 2.5kW indoor unit on the upstairs landing. Both rooms heat in winter and cool in summer, each with its own remote and set up on the Haier app, so they can be controlled from a phone.
Why one outdoor unit can run more indoor kW than it’s rated for
On paper there is 6.0kW of indoor units on a 5.5kW outdoor unit. That is normal for a multi-split and it’s called diversity: you rarely need both rooms flat out at the same moment, and when you do, the outdoor unit shares its power between them. It means a smaller, quieter and cheaper outdoor unit than adding the rooms up would suggest. See whole house heating for a short animation of how it works.
Room to grow
The outdoor unit has three ports and only two are in use. If another room is wanted later, a third indoor unit can be added to the same outdoor unit, with no second unit on the wall.
How we fitted it
- Survey. Each room sized separately: 3.5kW for the kitchen, 2.5kW for the landing.
- Pipework. Run up the outside of the house in insulated pipe to the landing, and through the kitchen wall downstairs, with white trunking inside where it shows.
- Pressure test. Tested with nitrogen at about 13 bar and held for 30 minutes before anything else.
- Vacuum test. Pulled down to 244 microns and held well under the 500-micron target, so the system was dry and sealed before the refrigerant was released.
- Commissioning. Heating and cooling tested on both rooms and both set up on the Haier app, by an F-Gas certified engineer. The whole job took two days.
We are local to Milton Keynes and cover MK1–MK17 and MK19. See air conditioning in Milton Keynes, or price your own rooms in two minutes — the calculator handles multi-room systems too.