School & Nursery Air Conditioning
Classrooms overheat: south-facing glazing, thirty bodies, laptops and a summer term that now regularly tops 30°C outside. This guide explains what the DfE's BB101 guidance says about overheating, when cooling is the right fix, how to plan a holiday installation, why ceiling cassettes dominate classroom work, 2026 costs per classroom and per block, and maintenance around the school year. We match schools, academies and nurseries with vetted, F-Gas certified engineers.
Classroom overheating and BB101
Building Bulletin 101 sets the design standard for new and refurbished school buildings in England. On overheating it uses adaptive thermal-comfort criteria — how many hours and by how much the indoor temperature exceeds a comfort threshold that moves with the outdoor temperature — rather than a single maximum, and requires designers to show classrooms will not overheat in a warm year. It also sets ventilation rates and CO₂ limits, so "shut the windows and cool it" is never the whole answer: fresh air must still be provided. For existing schools BB101 is not retrospective, but it is the benchmark a head, bursar or trust estates team uses to justify spending. The practical hierarchy: reduce solar gain (shading, film), improve ventilation (cross-ventilation, night cooling), add ceiling fans, then add cooling where rooms still fail — typically top-floor, south- and west-facing classrooms, IT suites, exam halls and nursery sleep rooms.
What is usually installed, room by room
| Space | Typical system | Why |
|---|---|---|
| Standard classroom, 50–70 m² | One or two ceiling cassettes, 5–7 kW each | Even four-way air throw, out of reach, walls left free; on a shared VRF or multi-split condenser |
| Nursery rooms and sleep rooms | Quiet wall-mounted or cassette units with locked controls | Low noise (around 19–25 dB(A) at low speed), gentle airflow away from cots, tamper-proof |
| Offices, staff room, medical room | Wall-mounted splits | Small rooms; see our office guide |
| Server / comms room | Dedicated split, 24/7, separate from the classroom system | See our server room guide |
Blocks of ten or more classrooms are normally designed as VRF / VRV with one or two condensers; smaller projects use multi-split.
Installing in the holidays
The school calendar is the installer's friend and constraint. The six-week summer break suits whole-block work; Easter and half-terms suit one or two rooms; a single classroom can be done over a weekend. Summer diaries fill early, so survey and order by spring. Agree in advance: condenser positions (ground cages or roof, away from playgrounds and neighbours), pipe routes and ceiling access, electrical capacity, asbestos information for older buildings, safeguarding if work overlaps term time, and handover training. Ask for the O&M manual, F-Gas records and warranty registration for the premises file.
School air conditioning costs in 2026
| Scope | Basis | Installed cost (2026) |
|---|---|---|
| Single small room (office, sleep room, server cupboard) | One wall-mounted split | £1,500–£3,000 |
| Typical 60 m² classroom | £150–£300 per m² | £9,000–£18,000 |
| Teaching block, per m² treated | Cassettes on VRF or multi-split | £150–£300 per m² |
| Whole block as VRF, per kW | Capacity-based | £350–£600 per kW |
Excludes electrical supply upgrades, asbestos removal, structural roof work and decoration. Independent schools and nurseries run as businesses may qualify for tax relief — see capital allowances.
Maintenance around the school year
A commercial maintenance contract with two visits a year timed to the Easter and October holidays keeps filters, coils and drains clean either side of the cooling season, leak-tests the system and produces the reports the premises file needs — roughly £75–£150 per unit per visit. Buildings with more than 12 kW of cooling need a TM44 inspection every five years. Site staff can rinse filters at half-terms and keep condenser cages clear of leaves and footballs.
Sources & methodology
- Department for Education, Building Bulletin 101: Guidelines on ventilation, thermal comfort and indoor air quality in schools (2018); Workplace (Health, Safety and Welfare) Regulations 1992, reg. 7.
FAQs
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