Hotel Air Conditioning: What Actually Works in London Bedrooms

Here is a conversation I have had more times than I can count. A general manager rings about a 60-room hotel in a converted London terrace. Half the guest complaints mention the room being too hot or too cold, the night porter has a drawer full of portable fan keys, and the bedrooms on the sunny side of the building need cooling in April whilst the rooms at the back still want heating. The existing system cannot do both. It was never chosen with a hotel in mind.

That last line is the whole problem, and it is fixable.

For most London hotels above a dozen rooms, the right answer is a VRF heat recovery system: quiet indoor units in each bedroom, guest controls tied to the keycard and window contacts, and outdoor plant sited to pass planning and not wake the neighbours. Heat recovery matters because a hotel is one of the few buildings where some rooms need heating at the same moment others need cooling, and the system moves the heat between them rather than paying for it twice. Smaller boutique sites can run happily on individual splits, and some large older hotels still sit on fan coil units. What follows is how to choose, and how to refit without closing the hotel.

The three systems you will actually be quoted for air conditioning for hotels

Every quote you receive for hotel HVAC will be one of three things, or a combination.

Individual splits. One outdoor unit per bedroom, or a small multi-split serving two or three. Cheap to buy, quick to fit, and each room fails on its own, which matters at 11pm when you have one broken unit rather than one broken hotel. The catch is the outside of the building: thirty bedrooms means thirty condensers, and on a London terrace there is nowhere to put them that planning, the freeholder or the neighbours will accept. Splits suit guest houses, annexes and boutique sites up to around ten or twelve rooms.

Fan coil units on chilled water. The traditional big-hotel answer. A chiller and boiler feed water to a fan coil in each room. Quiet, hard-wearing, familiar to every hotel maintenance engineer over fifty. The weakness is the classic four-pipe versus two-pipe problem: on a two-pipe system the whole building is in heating or cooling at once, which is exactly the complaint in the opening scene.

VRF, and specifically heat recovery VRF. One or two outdoor units serve every bedroom through refrigerant pipework, each room gets its own indoor unit and its own control, and a heat recovery system lets some rooms heat whilst others cool. Our page on VRF air conditioning goes into the technology properly. The headline for a hotelier is this: it is the only one of the three that solves the sunny-side, shady-side problem without throwing energy away.

	Individual splits	Fan coils (chilled water)	VRF heat recovery
Best fit	Guest houses, annexes, up to roughly 12 rooms	Large existing hotels, conference floors	Most London hotels from about 15 rooms up
Heating and cooling at the same time	Yes, per room	Only on four-pipe systems	Yes, and it recovers the heat
Outdoor plant	One condenser per room, planning headache	Chiller, usually plant room or roof	One or two condenser groups
Failure impact	One room down	Whole zone down if the chiller stops	One room down per indoor unit
Refrigerant in bedrooms	Yes, small charge	No, water in the room	Yes, small charge

Why heat recovery suits a hotel better than almost any other building

Picture a hotel on a March afternoon. The kitchen and the gym reject heat all day. South and west facing bedrooms gain heat through the glass even when it is single figures outside. The north-facing rooms at the back are cold until evening. A guest in 204 wants 19°C and a guest in 207 wants 24°C, and both paid the same rate.

A heat recovery VRF system takes the heat it removes from the warm rooms and delivers it to the cold ones. You stop paying a boiler to make heat in one corner of the building whilst paying a condenser to dump it from another. The recovered heat can also pre-heat domestic hot water, the biggest energy load in a hotel after space conditioning. This is not theory. LG's case study on the 143-room Bristol Hotel leans on the same mechanism: a heat recovery VRF that "allows each room to operated in heating or cooling mode independently", with a Hydro Kit that "generates domestic hot water (DWH) by reusing recovered heat during cooling operation" (The Bristol Hotel heat recovery case study, LG Global). The grammar is theirs. The principle is sound.

One honest caveat. VRF puts refrigerant pipework through the building, and the charge adds up across forty bedrooms. That brings F-Gas obligations, covered below, and it makes the quality of the brazed joints genuinely important. A badly installed VRF system is a worse problem than a badly installed split, because everything shares one circuit.

Bedroom noise: how indoor units are specified for sleep

A hotel bedroom is the harshest noise environment in commercial air conditioning. The guest is asleep two metres from the unit, the room is otherwise silent at 3am, and a fan that would be invisible in an office becomes the thing that generates a one-star review. Every hotelier who has had the "humming noise" complaint knows how quickly it poisons a room's rating.

The fix happens at specification, not after installation. Manufacturers publish sound pressure levels for every indoor unit at each fan speed, and the right bedroom unit is the one whose lowest setting is quiet enough for sleep whilst still holding temperature. In practice that means slim ducted units above the bathroom lobby, or high-wall units chosen for their low fan speed figures, never a cassette blasting down onto the bed. Anti-vibration mounts and properly supported pipework matter just as much, because most "noisy unit" callouts I see are installation faults: a pipe touching a stud wall and turning the whole partition into a sounding board.

Ask any bidder two questions. What is the published sound pressure of the proposed indoor unit at its lowest fan speed, and how will the pipework be isolated from the bedroom structure. A blank look on either means you need another bid.

Guest controls, keycards and stopping the waste

Guests behave like guests. They open the window with the cooling on full, they leave the room at 18°C for a day out, and they override whatever you tell them, because the room is theirs for the night. Notices on the wall are hopeless. The engineering answer is to take the decision out of the loop.

Three interlocks do almost all the work. A keycard switch that sets the room back to an economical drift temperature when the card is out. A window contact that drops the indoor unit to standby when the window opens. And setpoint limits on the controller itself, so "full cold" means 20°C rather than 16°C. The guest still feels in control, because they are, within a band that does not bankrupt you. Most VRF central controllers support all three, and tying them into the door lock is routine work.

The saving is real money. Bedrooms sit empty for a third of the day even at good occupancy, and every degree of unnecessary cooling in an empty room is a direct cost.

Outdoor plant, planning and London neighbours

London makes the outdoor unit the hardest part of the job. A hotel condenser group is not a domestic heat pump on a bracket. It is commercial plant, and on a commercial building it normally needs planning permission, particularly in the conservation areas where half of London's hotels sit. GOV.UK is blunt about the principle: "Planning permission is only needed if the work being carried out meets the statutory definition of 'development'", and fixing substantial plant to a roof or elevation of a commercial building almost always does, with the warning that "if development is carried out without the necessary planning permission, this may lead to enforcement action" (When is permission required, GOV.UK). Our post on planning permission for air conditioning walks through how this lands in practice, including listed buildings.

Noise is the other half of siting. The nearest bedroom window to your condenser may belong to the house next door, and environmental health officers respond to noise complaints with measurement equipment. Siting on a screened roof, on anti-vibration mounts, with fans selected for night duty, is a design decision taken before the planning application goes in, not a fix afterwards. I have seen a hotel have to restrict its cooling at night because of one badly sited condenser. The rooms it served were the best rooms in the building.

F-Gas leak checks and TM44: the compliance a hotel cannot dodge

A hotel VRF installation holds enough refrigerant to sit firmly inside the F-Gas rules. GOV.UK sets the leak check bands in CO₂ equivalent: from 5 to less than 50 tonnes CO₂e the equipment needs checking "at least once every 12 months", from 50 to less than 500 tonnes "at least once every 6 months", and fitting automatic leak detection lets you "double the period of time allowed between leak checks" (Checking F gas equipment for leaks, GOV.UK). A forty-bedroom heat recovery system lands in the first band: annual leak checks and refrigerant records are the minimum, and our guide to F-Gas compliance basics covers the record-keeping.

Then there is TM44. Any air conditioning system with an effective rated output over 12kW needs an energy inspection, and a hotel system passes that threshold on the first floor. The GOV.UK guide states that "all air conditioning systems with an effective rated output of more than 12kW must be regularly inspected by an energy assessor", that "the inspections must be no more than five years apart", and that Trading Standards can issue a penalty charge, currently £300, for not having a report (A guide to air conditioning inspections in buildings, GOV.UK). The fine is trivial. The report is not: a decent assessor will tell you things about your controls that pay for themselves. Our TM44 inspections guide explains what the assessor actually looks at.

Servicing around occupancy

Hotel maintenance fails in a specific way: the filters clog on the rooms that run hardest, which are the rooms you sell most, so the complaints arrive precisely where your revenue is. The answer is a servicing plan built around occupancy rather than the calendar. Filter and coil cleans land on shoulder periods and low-occupancy midweeks, noisier work is scheduled against the room bookings, and every bedroom is on a rota your front office can see, so a unit due a visit is simply not sold that night.

That is how we would set up planned air conditioning servicing for a hotel, and if you are comparing contracts, the questions worth asking are set out in what to specify in an air conditioning maintenance contract. F-Gas leak checks and TM44 dates belong in the same plan, not in a drawer.

Refurbishing a working hotel without closing it

This is the question nobody's brochure answers, and it is usually the real one. The hotel cannot shut for three months: the cash flow will not stand it, and neither will the reviews. So the refit happens floor by floor.

The sequence that works looks like this. The outdoor units, main pipework risers and the new controls backbone go in first, routed through corridors, riser cupboards and roof voids with the hotel fully trading, because almost none of that work needs to enter a bedroom. Then one floor comes out of inventory at a time, typically for two to three weeks: old units out, new indoor units in, connections, controls, commissioning. That floor goes back on sale before the next one drops out, and the old system keeps serving the floors still trading until their turn comes.

Done properly the hotel loses one floor of revenue in rotation rather than the whole building, and guests on trading floors never hear a core drill before 10am. I will not pretend it is painless. It is far less painful than a closure, and a contractor who has done it before will show you the floor-by-floor programme in the tender.

Frequently asked questions

What is the best air conditioning system for a hotel?

For most UK hotels above a dozen or so rooms, a VRF heat recovery system with individual bedroom units and central control. It lets some rooms heat whilst others cool and needs only one or two outdoor condenser groups, which matters for planning. Smaller boutique properties often suit individual splits, and some large existing hotels sensibly keep fan coils on chilled water.

Can you install air conditioning in a listed hotel?

Yes, but the route is narrower. Listed building consent sits alongside planning permission, and indoor equipment usually needs to be ducted or concealed so nothing modern touches the historic fabric. It is done regularly in London, but it needs designing with the conservation officer in mind from day one.

How do hotels stop guests wasting air conditioning?

With hardware, not notices. A keycard switch that sets the room back when the guest leaves, a window contact that pauses the unit when the window opens, and setpoint limits so the controller will not go below a sensible temperature. The guest keeps comfort control within a band, and the empty-room waste largely disappears.

Does hotel air conditioning need an F-Gas leak check?

Almost certainly yes. The duty depends on the total charge expressed in CO₂ equivalent. From 5 tonnes CO₂e upwards, GOV.UK requires checks at least every 12 months, more often on larger systems, and a hotel-scale VRF installation will normally be in scope. Records must be kept.

What is a TM44 inspection and does my hotel need one?

A statutory energy inspection of an air conditioning system by an accredited energy assessor. Any system over 12kW effective rated output needs one, which captures every hotel system beyond a handful of rooms, and inspections must be no more than five years apart. Trading Standards enforce it, with a penalty charge for missing reports.

Can a hotel replace its air conditioning without closing?

Yes, and this is how most working hotels do it. Outdoor plant and main pipework go in whilst the hotel trades, then bedrooms are refitted one floor at a time, each floor out of inventory for a couple of weeks with the old system still serving the rest. Revenue dips slightly instead of stopping.

Getting hotel air conditioning right in London

The hotels that get this right treat it as a building project with a guest in it, not an equipment purchase. The system is chosen for the building's actual behaviour, bedrooms are specified for sleep, controls quietly stop the waste, and the refit is programmed around occupancy.

If you are planning a new install or a floor-by-floor refit, talk to us before the tender goes out. We design and install commercial air conditioning across London, and we will tell you honestly whether your building wants VRF, splits or something it already has, including the sites where the answer is to fix the controls and leave the plant alone.

About the author: Ali Elm runs Be Cool Refrigeration & Air Conditioning, a family-run London firm that has been installing, servicing and repairing commercial refrigeration and air conditioning since 2004. His F-Gas certified team has delivered more than 2,000 projects across London and the South East.

Last updated: 5 October 2026