Ducted air conditioning in the UK: the BTU your home needs, what installing it costs and when a heat pump grant applies
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Ducted air conditioning in a UK home is sized in BTU and paid for in two halves. By the load of a worked technical example, a 5.3 kW unit (about 18,100 BTU/h) covers some 73 m², and the ducts, labour and ceiling often cost more than the unit. If it heats too, GOV.UK's Boiler Upgrade Scheme offers £2,500.
How much ducted air conditioning costs in the UK, with the unit and the works separated
The first screen of this search is mostly installers and shops, and they sell the unit, the installation or both: a closed quote closes better. The split between the two is published by two UK cost guides. Checkatrade, the UK trades platform, gives the unit on its own: a 12,000 BTU ducted ceiling unit at £990, 18,000 BTU at £1,250 and 24,000 BTU at £1,450, with ductwork at £180 a metre on top (its price table is dated May 2026).
Aircon Adviser, a UK cost guide dated 6 August 2026, prices the whole job: a typical whole-home installation at £6,000 to £15,000, with the equipment at £4,000 to £10,000, the ductwork and grilles at £2,000 to £6,000 and the labour at £2,000 to £5,000. It says its own figures come from UK installers and cost aggregators, not from any official body, and that is how to read them: as bands to check a quote against.
The line that moves most is not the unit, it is the ceiling. With the ducts already in, the job is to hang the indoor unit and connect it. Without them, the ducts, their insulation and the condensate fall need a void, and in most homes that means a suspended ceiling or a boxed-in bulkhead along the hallway and landing: Checkatrade puts a suspended ceiling at £22 to £35 per square metre before decorating (September 2026).
Air conditioning BTU calculator for a ducted system: how many BTU your home needs, and why 25 per square foot is only a rule
The rule that UK calculators publish is simple: 20 to 25 BTU per square foot of floor, which is 215 to 269 BTU per hour per square metre (Material Calculator, reviewed on 8 September 2026). The technical sum behind a load calculation is published too, but in Spain: the IDAE technical guide to air conditioning, a recognised document of the Spanish building services rules, works through a two-storey home with 5,309 W of total load over 63.5 m², 85 W per square metre, and 4,500 W at the same time, 85% of that sum. With those two figures it chooses a 4.8 kW unit per floor. In BTU, the worked example lands at about 247 per square metre, inside the UK rule's band; the difference between homes comes from insulation, sun and the roof, and the calculator below adds them one by one.
Air conditioning BTU calculator for a ducted home, with the UK installation cost
The air conditioning BTU calculator from m8d.io sizes a ducted system from the load of a worked technical example, shows the sum next to the 25 BTU per sq ft rule and warns when a unit would be oversized; below it, the installation cost split into the unit and the works, with UK sources. Free, no sign-up. Example: 70 m² with a 2.5 m ceiling needs about 17,300 BTU/h (5.06 kW), against about 18,800 by the rule of thumb.
The size: how many BTU per hour and how many kilowatts your home needs
The sum, in full: 70 m² at 85 W/m² is 5,950 W of total load; times 1.00 for your home's settings, 5,950 W; times 0.85 for simultaneity, 5,058 W. And 5,058 watts times 3.412 is 17,256 BTU per hour.
That is 1,600 BTU/h more, 9% more machine for the same home. And more does not mean safer: the IDAE guide puts the floor of an inverter unit at around 30% of its load, so an oversized one spends the summer starting and stopping instead of holding the temperature, which is exactly what an inverter is paid for.
At 5.06 kW, size does not decide who can fit it: in Great Britain the refrigerant circuit is connected by an F gas certified technician whatever the size, and the yearly leak check starts at 5 tonnes of CO2 equivalent, about 7.4 kg of R32 or 2.4 kg of R410A.
The cost: which part is the unit and which part is the works
- ItemRange
- The unit, 18,000 to 24,000 BTU classIndoor and outdoor unit. Checkatrade, May 2026, up to 100 m²; Aircon Adviser, 6 August 2026, above£1,250 to £1,450
- Installation labourAircon Adviser cost guide, 6 August 2026£2,000 to £5,000
- Ductwork and grillesDepends on your home. Aircon Adviser cost guide, 6 August 2026£2,000 to £6,000
- Electrical workAircon Adviser cost guide, 6 August 2026£150 to £1,000
- Suspended ceiling to hide the ducts · 20 m²Depends on your home. Checkatrade suspended ceiling guide, September 2026£440 to £700
- TotalUnit plus works, with the ranges of both sources added at their extremes£5,840 to £14,150
The sum, in full: the unit for 70 m² is £1,250 to £1,450 and the works add up to £4,590 to £12,700, with 20 m² of suspended ceiling included. The extremes are added separately, so the first figure is everything cheap and the second everything dear: your quote will land in between.
What this range does not include: the 20 to 30% uplift that Aircon Adviser gives for London and the South East, and any planning consent, which the same guide says is stricter for listed buildings and conservation areas. Ask for both as separate lines in the quote.
The base load of 85 watts per square metre and the simultaneity factor of 0.85 come from the worked home example in the Spanish IDAE technical guide to air conditioning with packaged units (June 2012): 5,309 W over 63.5 m² and 4,500 W at the same time on that floor. With those two figures this calculator returns 4.59 kW for that home, and the guide selects the 4.8 kW commercial unit. The adjustments for insulation, sun, floor and ceiling height are orientations declared as such, to compare cases: the load calculation for a real home is done by the designer or installer. The rule of 25 BTU per sq ft is the top of the 20 to 25 band published by Material Calculator (reviewed on 8 September 2026). The cost ranges are UK market readings from Checkatrade (May and September 2026) and Aircon Adviser (6 August 2026), not the price of any product. One watt is 3.412 BTU per hour: a unit conversion, not a measurement.
Ducted air conditioning that also heats: the £2,500 Boiler Upgrade Scheme grant for an air-to-air heat pump
In a British home a ducted system is rarely bought for a few hot weeks alone. Run in reverse, the same outdoor unit and ducts heat the rooms, and that makes it an air-to-air heat pump, which the UK government now funds: the Boiler Upgrade Scheme lists £2,500 towards an air-to-air heat pump, next to £7,500 for an air source or ground source heat pump (GOV.UK, read on 27 September 2026).
The conditions are the scheme's own. You have to own the property and be replacing fossil fuel heating, such as oil, gas, electric or LPG; most new builds and social housing are out; the installer applies on your behalf on the Ofgem website, has to be MCS certified, and has to commission the system within 120 days of applying. A unit that declares its heating output separately, like the Orbegozo DUCT 128 with 3.78 kW of heating next to its 3.49 kW of cooling, is the kind of figure the installer will size that heating from.
Ducted or split air conditioning in the UK: what decides it, with the unit prices side by side
Checkatrade prices a 12,000 BTU wall-mounted split at £750 for the unit and about £1,150 to install, and a 12,000 BTU ducted ceiling unit at £990 for the unit alone, with the ductwork at £180 a metre on top (May 2026). The unit is not where the two differ.
That ducted air conditioning costs more to run because it conditions the whole home.
It costs more if it is used for the whole home at once, which is exactly what zoning prevents. With a damper per room the simultaneity factor drops and the unit works at part load, where an inverter is most efficient. Without zoning, one thermostat decides for every room and the empty ones are conditioned too.
That a split system is the cheap option.
It is, for one or two rooms. For four, it stops being a split and becomes four indoor units, four remotes and a multi-split outdoor unit; Aircon Adviser puts a multi-split for three or four rooms at £3,500 to £7,000. The real difference is still the works, not the machine.
That a ducted system cannot be heard.
The unit sits far away in a ceiling void, which lowers the noise in the room. But the air has to arrive through a duct, and the more pressure the fan has to overcome, the faster the air moves and the louder the grille. It is the same figure that decides the reach: the available static pressure.
m8d rule: If you are torn between ducted and split, the question is not which cools better: it is how many rooms you will cool at once and whether the ducts already have a route. With two rooms and no route, the works eat the difference.
Ducted air conditioning for 50, 70, 90, 110 and 130 m²: the BTU worked out
The same sum, with the worked example's load, the simultaneity factor applied, a 2.5 m ceiling, mixed sun and a home rated EPC A to C. What changes with the floor area is not the proportion: it is which size of unit you land on, and when one unit stops being the answer. Of the two units in this guide with a UK listing, the Orbegozo DUCT 128 covers up to about 48 m² and the Hisense ADT52UX4RSCL4 about 73 m².
| Ducted unit | Capacity it declares | In other units | Floor area it covers | What its listing does not say | |
|---|---|---|---|---|---|
| Hisense ADT52UX4RSCL4 view › | 4,558 frigories/h | 5.3 kW · 18,100 BTU/h | up to 73 m² | SEER, SCOP, static pressure and refrigerant | View › |
 Orbegozo DUCT 128 view › | 3,000 frigories/h cooling, 3,250 kcal/h heating | 3.49 kW · 11,900 BTU/h | up to 48 m² | SEER, SCOP, static pressure and refrigerant | View › |
The capacity is the one each listing declares, read on 8 September 2026; the other units are conversions (divide frigories by 0.86 for watts, multiply watts by 3.412 for BTU per hour). The floor area is the calculator's result with the worked example's load, a 2.5 m ceiling, mixed sun and simultaneity applied. The right-hand column is the census: none of the 22 ducted units counted on Amazon Spain declares SEER, SCOP or available static pressure.
The reading that matters is in the last bars. From about 110 m², one unit for the whole home has a problem that is not power: when only two rooms are in use, the unit has to run far below its load, and the IDAE guide puts the floor of an inverter at around 30%. That is why its two-storey example does not fit one big unit: it fits two of 4.8 kW, one per floor. At 130 m², one large unit with zoning and two smaller ones solve the same load, and the difference between the two solutions is, again, the works.
The real drawbacks of ducted air conditioning, including the one that can stop the installation
The drawbacks everyone lists are three: it costs more, it needs building work and it lowers a ceiling. All three are true and all three are solved with money. A fourth is not, and hardly anyone mentions it.
The indoor unit often goes in the ceiling void of a bathroom, and that room can be too small for the refrigerant. Refrigerants have a practical limit of concentration per cubic metre of the room, and the IDAE guide works it through literally: a system with 6 kg of R-407C in the ceiling void of a bathroom of 4 m² and 3 m high is 12 cubic metres; at a practical limit of 0.31 kg per cubic metre, the maximum charge is 3.72 kg, so it cannot go there. For R410A the same guide gives 0.44 kg per cubic metre. Its way out is to connect that void with other rooms or outdoors through openings of 500 cm² of free area, one more line in the quote.
The capacity on a ducted unit's listing is not what reaches the last room, and no listing gives the figure that explains it
A ducted unit has to push air down a duct, round corners, through grilles and into the room at the far end. That effort is called the available static pressure, it is measured in pascals, and it separates a unit that serves your home from one that only serves a short corridor.
We counted 22 ducted air conditioning units on sale on Amazon Spain on 8 September 2026, over 27 searches and 162 separate listings. Ten declare an energy class. None declares its SEER, none its SCOP and none its available static pressure. And five of the 22 do not say in their title how much capacity they have.
A capacity: 5 kW, 4,558 frigories per hour, 18,000 BTU or 3,000 kilocalories. Four units for the same quantity, and no listing in the census gives two at once.
Daikin states that its ADEA-A ducted series offers static pressure of up to 150 pascals and sells it as an advantage, because it is what makes flexible ducts of different lengths workable; and adds that the static pressure can be changed from the remote control to optimise the air volume supplied. The table of a commercial ducted range in the IDAE guide gives available pressures of 50 to 70 pascals. Between 50 and 150 there are three times the pressure for pushing that air further.
Daikin's ADEA-A product page, read on 8 September 2026; the commercial range table in the IDAE technical guide to air conditioning with packaged units, June 2012; and the count of the 22 Amazon Spain listings on 8 September 2026.
m8d rule: If a ducted unit's listing does not give its available static pressure in pascals, the capacity in the title is the maker's rated figure, not your home's: ask for it before you sign, because it decides whether the air reaches the last room.
The practical consequence is a conversion, and it fits in two sums. Frigories per hour divided by 0.86 give watts; watts times 3.412 give BTU per hour. With that, the 4,558 frigories of the Hisense ADT52UX4RSCL4, the 18,000 BTU of the ADT52UX4RCL8 from the same series (a sibling with no UK listing) and a unit sold as 5 kW are three ways of writing the same size of machine: 5.3, 5.28 and 5 kW.
And the warning that saves most money when comparing prices online. Searching one of the units in this guide on Google's Spanish price comparison on 8 September 2026 returned 40 offers with prices ten times apart for what looked like the same model. The reason was in the titles: the cheaper half said indoor unit, cassette or without panel, and sold half a system. A ducted system is two appliances, the ducted indoor unit and the outdoor unit, and the price that compares is the price of both.
Who can install ducted air conditioning in the UK: F gas certification and leak checks
The Spanish edition of this guide is built on Spanish rules (the building services regulations and the EU fluorinated gas regulation of 2024). In Great Britain the refrigerant side runs under its own F gas regime, while Northern Ireland stays in the European Union system, as GOV.UK's F gas guidance puts it (updated on 12 May 2025).
- F gas certification. The refrigerant circuit of a split or ducted system is installed, filled and maintained by an F gas certified technician, working for a certified company; GOV.UK's guidance on qualifications and company certification is where both are set out.
- Leak checks. GOV.UK sets them by the tonnes of CO2 equivalent of gas in the system: from 5 to under 50 tonnes, once a year. With R32, whose global warming potential in the F gas rules is 675, that takes 7.4 kg of charge; with R410A, at 2,088, only 2.4 kg. The same unit can change duty with the gas inside it, and the figure is on the outdoor unit's plate, not in the listing.
- The grant route. For the £2,500 Boiler Upgrade Scheme grant, the installer has to be MCS certified and applies on your behalf on the Ofgem website (GOV.UK).
Hisense ADT52UX4RSCL4 view ›
The one for a home of around 70 m²: 5.3 kW of cooling, about 18,100 BTU/h, which the sum above covers at 70 m² and falls short of at 90. It publishes neither SEER, SCOP nor static pressure, so ask the installer for all three in writing before you sign.
- Its listing gives the capacity as 4,558 frigories per hour, the Spanish unit: divided by 0.86 that is 5.3 kW, and times 3.412 about 18,100 BTU/h, the size British installers sell as an 18,000 BTU unit.
- It covers the calculated load of about 73 m² (786 sq ft) with the simultaneity factor applied: a home of around 70 m², or one floor of a larger one.
- It declares class A++ without the SEER figure behind it, which is the pattern of the ten listings, of 22 ducted units counted on Amazon Spain on 8 September 2026, that give an energy class.
- 5.3 kW: the 18,000 BTU class
- Covers about 73 m² with simultaneity
- Class A++ declared for cooling
- No SEER or SCOP published
- No available static pressure declared
- Does not say which refrigerant it uses
Orbegozo DUCT 128 view ›
The one that writes its heating output next to its cooling output, and in the UK that is the figure that matters, because a ducted system that heats is an air-to-air heat pump. At 3.49 kW of cooling it suits a flat or a living area of about 48 m²; for the Boiler Upgrade Scheme, the grant section explains what the installation needs.
- Its listing gives 3,000 frigories per hour of cooling (3.49 kW, about 11,900 BTU/h) and 3,250 kcal/h of heating (3.78 kW). The heating output of a heat pump is not its cooling output, and here both are written down.
- It covers the calculated load of about 48 m² (517 sq ft) with simultaneity: a flat, or the living area of a larger home, and just under what a UK 12,000 BTU unit is sold for.
- Orbegozo is a Spanish brand with its own service network there; like every one of the 22 listings counted on Amazon Spain, its spec publishes neither SEER, SCOP nor static pressure.
- Heating and cooling output both declared
- Heat pump written in its own title
- 12,000 BTU class for a flat or a living area
- Capacity given in kilocalories: convert before comparing
- No SEER or SCOP in its spec
- No available static pressure declared
Ducted air conditioning questions asked in the UK before getting a quote
How much does ducted air conditioning cost in the UK?›
Aircon Adviser puts a typical whole-home installation at £6,000 to £15,000 (6 August 2026), with the equipment at £4,000 to £10,000, the ductwork and grilles at £2,000 to £6,000 and the labour at £2,000 to £5,000. For a single ducted unit, Checkatrade gives £990 for a 12,000 BTU ducted ceiling unit, with ductwork at £180 a metre on top (May 2026).
What are the disadvantages of ducted air conditioning?›
It costs more than a split, it needs ducts and usually a suspended ceiling or bulkhead, and without zoning one thermostat conditions every room. Two more are rarely said: listings do not give the available static pressure that decides whether the air reaches the last room, and a small bathroom ceiling void can be too small for the refrigerant charge.
Is it worth getting ducted air conditioning?›
It pays off when several rooms are cooled or heated at once and the ducts have a route, in a renovation or a loft for example. For one or two rooms a split is cheaper. And in the UK it can be the heating too: as an air-to-air heat pump it can get £2,500 from the Boiler Upgrade Scheme if it replaces fossil fuel heating.
How many BTU does a home need for ducted air conditioning?›
With the worked example's load of 85 W per square metre and the 0.85 simultaneity factor, 70 m² needs about 17,300 BTU/h (5.06 kW) and 90 m² about 22,200 BTU/h (6.5 kW). The rule of 25 BTU per sq ft gives about 18,800 and 24,200. Insulation, afternoon sun and a roof above push the figure up.
What size room will a 12000 BTU air conditioner cool?›
12,000 BTU/h is 3.52 kW. With the worked example's load it covers about 48 m², some 520 sq ft; by the rule of 25 BTU per sq ft it covers 480 sq ft, about 45 m². In a top-floor room with afternoon sun, both shrink.
Can ducted air conditioning heat a house?›
Yes, if it is a reverse-cycle system: then it is an air-to-air heat pump. The Orbegozo DUCT 128 in this guide declares 3.78 kW of heating next to 3.49 kW of cooling. GOV.UK's Boiler Upgrade Scheme gives £2,500 towards an air-to-air heat pump when it replaces fossil fuel heating and an MCS certified installer applies.
Who can install air conditioning in the UK?›
In Great Britain the refrigerant circuit is handled by an F gas certified technician working for a certified company, whatever the size of the unit. For the Boiler Upgrade Scheme the installer also has to be MCS certified. Leak checks become a yearly duty from 5 tonnes of CO2 equivalent of gas.
How the ducted air conditioning sums in this guide were done, and where each figure comes from
We went through the whole Amazon Spain catalogue on 8 September 2026: 27 searches, 162 separate listings and 22 ducted units, counting one by one what the title each is sold with declares, because that is what a buyer reads. The census figures come from there, and they are Spanish listings.
The thermal load and the simultaneity factor are those of the worked home example in the IDAE technical guide to air conditioning with packaged units, a recognised document of the Spanish building services rules; we found no UK public source with a worked home example, so it is cited as Spanish. The adjustments for insulation, sun, floor and ceiling height are orientations declared as such. The UK rule of 25 BTU per sq ft is Material Calculator's (reviewed on 8 September 2026).
The UK cost ranges are market readings: Checkatrade (air conditioning guide updated in May 2026, suspended ceiling guide in September 2026) and Aircon Adviser (6 August 2026). The grant and the F gas rules were read on GOV.UK on 27 September 2026. Two of the seven units of the Spanish edition have a listing on Amazon UK today, and they are the two here; availability changes from country to country, and the buttons take you to the Amazon store of yours.
The ones behind the specific figures on this page, with the date each was read.
- GOV.UKBoiler Upgrade Scheme: what you can get£2,500 towards an air-to-air heat pump, £7,500 for air source and ground source. Read on 27 September 2026.
- GOV.UKBoiler Upgrade Scheme: check if you're eligibleOwning the property, replacing fossil fuel heating (oil, gas, electric or LPG), 120 days to commission. Read on 27 September 2026.
- GOV.UKBoiler Upgrade Scheme: how to applyThe MCS certified installer applies on the Ofgem website. Read on 27 September 2026.
- GOV.UKF gas in refrigeration, air conditioning and fire protection systemsGreat Britain and Northern Ireland under different F gas systems; certification guidance. Updated on 12 May 2025, read on 27 September 2026.
- GOV.UKChecking F gas equipment for leaksYearly checks from 5 to under 50 tonnes of CO2 equivalent. Read on 27 September 2026.
- Aircon AdviserDucted air conditioning cost: UK price guide (2026)Whole-home, equipment, ductwork, labour, electrical and zoning bands, multi-split for three or four rooms, and the London uplift. Dated 6 August 2026, read on 27 September 2026.
- CheckatradeAir conditioning installation costDucted ceiling units of 12,000, 18,000 and 24,000 BTU, ductwork per metre and wall-mounted split prices, from a price table dated May 2026. Read on 27 September 2026.
- CheckatradeSuspended ceiling cost£22 to £35 per square metre. Updated in September 2026, read on 27 September 2026.
- Material CalculatorAir conditioner calculatorThe rule of 20 to 25 BTU per square foot. Reviewed on 8 September 2026, read on 27 September 2026.
- IDAE (Spain), recognised document of the Spanish building services rules, June 2012Guía técnica de instalaciones de climatización con equipos autónomosThe worked home load, the commercial range table with available pressures and charges, and the practical refrigerant limit. Read on 8 September 2026.
- DaikinADEA-A ducted series, available static pressureExternal static pressure of up to 150 Pa, adjustable from the remote. Read on 8 September 2026.
- m8d.io, 27 searches and 162 separate listingsCensus of ducted units on Amazon SpainThe 22 ducted units and what each title declares: capacity, unit, class, SEER, SCOP, static pressure and refrigerant. Read on 8 September 2026.
This decision is not made between brands: it is made between a capacity figure and a quote that almost nobody splits. If you ask us where to start, we recommend asking for the quote with every item on its own line before comparing units, because in the UK figures above the works weigh as much as the machine, or more, once there is no route for the ducts, and that part depends on your home, not on the catalogue.
With the capacity, the rule runs the opposite way to what the price suggests: the extra kilowatt always looks cheap in a catalogue and is paid for every summer. With the worked example's load, a home of 70 m² needs about 17,300 BTU per hour, and in this guide that is the Hisense ADT52UX4RSCL4 view ›; a flat or a living area of about 48 m² is the Orbegozo DUCT 128 view ›, which also declares its heating.
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