
Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System
Available to order — dispatched on the lead time shown below.
Trade pricing available — apply or sign in for your trade rate
Retail prices include VAT.
The Fujitsu Airstage KM Series 4.2kW split system is the ideal choice for larger rooms or open-plan living areas that require robust climate control. This high-performance unit delivers rapid cooling and heating, ensuring your space reaches the desired temperature quickly and efficiently. With its integrated Wi-Fi module, you can easily monitor and control your home environment via a smartphone app, providing ultimate convenience and energy management. The system utilizes advanced R32 refrigerant technology, which is more environmentally friendly and efficient than older alternatives. Its sleek, modern design ensures it remains unobtrusive, while the quiet operation mode makes it perfect for living rooms where comfort and silence are paramount. As a reverse-cycle heat pump, it provides an excellent alternative to traditional heating systems during the winter months. This unit requires professional installation, guaranteeing a high-quality setup that will provide years of reliable, energy-efficient service for your home.
Need it installed?
We'll match you with a local HVAC engineer.
Smart-home ready
Connects natively with the systems below — control by app or voice.
- Free UK mainland delivery on in-stock units
- Manufacturer warranty included
- 14-day returns
Technical documents & videos
More from Fujitsu →Official Fujitsu manual
The manufacturer's PDF for this model is being sourced and will be downloadable here.
Airstage Digital Catalogue
Fujitsu catalogue — open the official flipbook in a new tab.
Full Specifications
Physical dimensions
Exact dimensions for this model are being confirmed with Fujitsu — ask us and we will send the cut sheet with mounting and clearance figures.
Description
The Fujitsu Airstage KM Series 4.2kW split system is the ideal choice for larger rooms or open-plan living areas that require robust climate control. This high-performance unit delivers rapid cooling and heating, ensuring your space reaches the desired temperature quickly and efficiently. With its integrated Wi-Fi module, you can easily monitor and control your home environment via a smartphone app, providing ultimate convenience and energy management. The system utilizes advanced R32 refrigerant technology, which is more environmentally friendly and efficient than older alternatives. Its sleek, modern design ensures it remains unobtrusive, while the quiet operation mode makes it perfect for living rooms where comfort and silence are paramount. As a reverse-cycle heat pump, it provides an excellent alternative to traditional heating systems during the winter months. This unit requires professional installation, guaranteeing a high-quality setup that will provide years of reliable, energy-efficient service for your home.
Compare similar units
Side-by-side specs for other split system ac in a similar BTU range.
Common questions about the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System
How many BTU is the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System?
The Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System has a cooling capacity of 14,000 BTU, suitable for Up to 45m².
What room size is the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System suitable for?
The Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System is recommended for rooms Up to 45m².
Can I install the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System myself?
No — this unit requires professional installation by a qualified F-gas engineer. Use our Find an Installer service to get matched with a local HVAC professional.
Is the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System smart-home compatible?
Yes — the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System supports Google Home, Amazon Alexa for app and voice control.
How long does delivery of the Fujitsu Airstage KM Series 4.2kW Wall Mounted Split System take?
This unit is dispatched in 2-3 working days. Delivery is then 1–2 working days to most UK mainland addresses, and 3–6 working days into the EU.
Filter by brand
Belaco
Stiebel Eltron
Broughton
Reznor
CIAT
Powrmatic
FlaktGroup
Swegon
Suntec
Costway
VYtronIX
Beldray
Clarke
Omega Altalfa
Dantherm
Amcor
Rhoss
Kelvinator
Westinghouse
York
Trane
Lennox
Black + Decker
Honeywell
Senville
AUX
Comfee
Whynter
Viessmann
Rinnai
Aermec
NIBE
Sinclair
Blyss
Fral
Whirlpool
Electrolux
Sharp
Cooper & Hunter
Daitsu
Dimplex
Bosch
Vaillant
Olimpia Splendid
Carrier
Toshiba
Mitsubishi Heavy Industries
DeLonghi
Hitachi
Pro Breeze
Meaco
AEG
Devola
Fujitsu
electriQ
Samsung
Woods
Midea
Haier
TCL
Hisense
LG
Gree
EcoAir
Panasonic
Sealey
Daikin
Mitsubishi ElectricAnnual energy savings estimate
How much this A+-rated unit could save versus a standard C-rated model, based on your usage.
This unit
134 kWh/yr
EER 11
Standard model
185 kWh/yr
EER 8
Est. saving
£13.60
50 kWh/yr less
Estimate based on the unit's energy-rating efficiency factor and cooling capacity (14,000 BTU). Actual savings vary with room size, climate and usage patterns.
Winter heating cost: this AC vs electric heaters
This unit reverses to heat your room in winter. Based on its 5 kW heat output used 5 hrs/day over a 150-day UK heating season at £0.27/kWh.
Electric heater / season
£950
This AC / season
£317
You save / season
£633
~67% less electricity
| Heating method | Electricity / season | Cost / season | Efficiency | Summer cooling |
|---|---|---|---|---|
| This heat-pump AC | 1172 kWh | £317 | Up to 300% | |
| Plug-in electric heater | 3517 kWh | £950 | 100% | |
| Electric storage heater | 3517 kWh | £950 | 100% |
Heat output estimated from this unit's 16,000 BTU/hr rating. A heat pump moves heat (COP ≈ 3), so it uses about a third of the electricity of a direct-electric heater for the same warmth. Actual savings vary with room size, insulation, tariff and usage. See the full comparison →
Share your savings
This heat-pump AC costs only £317/season to heat a room vs £950 for an electric heater - that's £633 saved. https://stockool.store/products/fujitsu-airstage-km-4-2kw-split
You may also need

Sealey Air Cooler, Purifier & Humidifier SAC04
Drop-ship available
Sealey Air Cooler, Purifier & Humidifier with Remote Control 13L SAC13
Drop-ship available
Sealey Air Cooler, Heater, Purifier & Humidifier SAC41





















































