System specification
Mitsubishi MXZ-2F40VF 4 kW outdoor unit. 2× MSZ-AP25VG indoor wall units (2.5 kW each) in bedroom and lounge. Coil pipework run through cavity wall. Outdoor unit wall-bracketed on the rear elevation (not visible from street). EDF GoElectric 5-hour overnight tariff at 9p/kWh for off-peak heating.
Property
Top-floor 2-bed flat, 1980s build, panoramic east-facing sea view, electric heating only
The South Shields flat is a typical top-floor 1980s coastal build — east-facing for the panoramic sea view, no central heating (just 1980s electric storage heaters and panel convectors), south-east elevation exposed to summer afternoon heat. The owner wanted both summer cooling and a more efficient winter heating route.
Air-to-water heat pump wasn't practical (top floor of a 4-storey block, no plant room, no radiator infrastructure). Air-to-air AC was the right answer — reversible heat pump operation gives both cooling and heating from a single appliance.
We specified the Mitsubishi MSZ-AP at 2.5 kW per indoor unit (right-sized for the 14 m² bedroom and 22 m² lounge under typical sea-air daytime gains). The MSZ-AP runs at 19 dB(A) at lowest setting — quieter than a fridge, essential for the bedroom unit running through summer nights. The MXZ-2F shared outdoor unit was wall-bracketed on the rear elevation with rubber isolation pads (block management approval received in advance — 3-week lead time).
Install completed in 2 days: day 1 outdoor unit + cavity-wall pipework, day 2 indoor units + commissioning + customer handover. EDF GoElectric tariff was already in place for the existing electric heating; AC slots straight in.
After 8 weeks of operation the owner reports the flat is comfortable in 22°C+ outdoor temperatures (impossible with the old fans) and the supplementary winter heating mode is delivering a SCOP of 4.1 — turning the old £1,400/year electric heating bill into ~£380/year of AC running cost at the off-peak tariff. The cooling-only summer use is approximately £40/year of additional electricity — negligible against the heating saving.
