Help and questions

We work street by street, and we’re working on yours. Every home on the street has had a leaflet. Why did I get a leaflet? explains more.

Before a leaflet goes out, we look at each home: public information about the building, such as its energy performance certificate, and the outside of the house in the street-level and aerial images anyone can see online. That’s enough to price most homes. Where it isn’t, we say so and arrange a look.

It’s the nine characters printed under the QR code on your leaflet, in three groups of three. Scan the QR code, or type the code on our home page. Letters that look alike, such as O and 0, are fine either way.

Fourteen days from when your leaflet arrived. Your price page shows the exact date.

Yes. It includes VAT and stands for 14 days. If you change your choices on your price page, such as a different room or a second unit, you see the new price straight away, before you commit to anything.

The units, the fitting, pipework, drainage, connecting the system to your electrics, commissioning, and the noise calculation for your neighbours. Our prices has the full list.

Sometimes we can’t be sure about a home from the outside. Rather than guess, we leave the price off and ask you to get in touch, so we can take a look.

Yes. You can choose up to three indoor units running from one outdoor unit, and the price updates as you choose.

No. We use public information and images anyone can see online. If we need a closer look, we ask you first.

Let us know your address and we’ll stop leafleting it.

Most split systems sold for UK homes can heat as well as cool. They run their refrigeration cycle in reverse, taking heat from the outdoor air and releasing it indoors, which makes them air-to-air heat pumps. They warm the rooms they serve but don't provide hot water. How air conditioning heats a room

It depends on the room's floor area, ceiling height, insulation, glazing, which way it faces and how much heat people and equipment add. Common sizes are 2.0 kW (about 7,000 BTU), 2.5 kW (about 9,000), 3.5 kW (about 12,000), 5.0 kW (about 18,000) and 7.0 kW (about 24,000). A proper assessment beats a rule of thumb, and a bigger unit isn't a better one. What size air conditioner do you need?

A portable unit needs no installation and can move between rooms, but its compressor sits in the room with you and it vents hot air through a hose, usually out of a window that then can't close fully. A fixed split system keeps the compressor outside, so it is usually quieter and more efficient, but it has to be installed. Fixed or portable: which is right for you

Quiet indoor units are often around 19–26 dB(A) on their lowest fan speed and get louder as the fan speeds up, while outdoor units are typically 45–50 dB(A) at 1 metre. These are sound pressure figures. Energy labels show sound power, which is a higher number for the same unit, so compare like with like, at the same fan speed. How loud is air conditioning?

Yes. A multi-split system connects two or more indoor units to one outdoor unit, and each room can usually have its own temperature and be switched on and off separately. Rooms in use at the same time normally all have to be heating or all cooling, and if the outdoor unit develops a fault, every room it serves is affected. Multi-split systems

An air conditioner that heats as well as cools is an air-to-air heat pump. It differs from the air-to-water heat pumps usually fitted in place of a boiler, which heat water for radiators and hot water rather than blowing warm air into rooms. Air-to-air heat pumps explained

The label shows SEER, the seasonal efficiency for cooling, and SCOP, the seasonal efficiency for heating. For both, a higher figure is better. The label also shows the unit's noise levels, and comparing units of a similar size gives the fairest picture. Energy labels: SEER and SCOP explained

Most wall-mounted split systems don't. They draw in the air already in the room, pass it through a filter, cool or heat it and blow it back out, so your home still needs its usual ventilation. Common air conditioning myths

The rooms that get hottest and where you spend long periods, often bedrooms, home offices, loft rooms and rooms with large south- or west-facing windows. A room that stays cool on its own may need nothing at all. Which rooms benefit most

A single wall-mounted split system with a short pipe run often takes half a day to a full day to fit. Multi-split systems, long or awkward pipe runs, condensate pumps and electrical work can all add time. How long installation takes

The dustiest job is drilling the hole through the outside wall for the pipes, cable and drain. A good installer will protect floors and furniture and clear up afterwards, and it helps to move furniture away from where the indoor unit will go. Preparing your home for installation

Usually there is one hole for each indoor unit, a few centimetres across, drilled through the outside wall behind or near the unit. It carries the refrigerant pipes, cable and condensate drain, and it is sealed once everything is through. What happens on installation day

Usually on a wall bracket or a ground stand, with space around it for air to flow, room to service it and somewhere for defrost water to drain. Pipe length limits, noise at the neighbours' windows and planning rules also decide where it can go. Where the outdoor unit can go

Every model has a maximum pipe length and a limit on the height difference between the units. Many small systems come pre-charged with refrigerant for a set length, often somewhere between 5 and 15 metres depending on the model, and longer runs need refrigerant added on site. Refrigerant pipework explained

Most systems need a dedicated circuit from the consumer unit, and an isolator switch near the outdoor unit is common. In England and Wales a new circuit is notifiable under Part P of the Building Regulations, so it must be done by an electrician registered with a competent person scheme or notified to building control. Electrical requirements

No. A split system is connected into a sealed refrigerant circuit on site, and in Great Britain anyone doing that work needs the right F-gas qualification, while the business doing it needs a company F-gas certificate. The electrical connection has its own rules too. Why installation needs a certified engineer

When cooling, the indoor unit collects water from the air, which runs through a drain pipe, by gravity where possible, to a suitable drain or waste pipe. Where the water can't run downhill, a small condensate pump carries it away. Where the water goes: condensate drainage

The system should be commissioned, which means testing the pipework for leaks, removing air and moisture from it, then running the system to check it cools, heats and drains properly. You should also be shown how to use it and clean the filters, and be given the paperwork, including a copy of the noise calculation. Commissioning and handover

There is no single right setting, but a comfortable temperature rather than the lowest one on the remote works best. Setting it much lower won't cool the room much faster; the system just keeps going until the room is colder than you wanted, and every degree lower makes it work harder. What temperature to set

It depends on how you use the room. An inverter system runs efficiently at low output, so holding a steady temperature while you are using a room often makes more sense than letting it heat up and pulling it back down. For a room left empty for many hours, switching off or using a timer usually uses less electricity. Leave it on or switch it off?

Dry mode takes moisture out of the air with less cooling than cool mode, which suits muggy days when a room feels clammy more than hot. The room usually still cools a little. The modes explained: cool, heat, dry, fan and auto

Yes, if your system has a heat mode, as most split systems do. It takes heat from the outdoor air even when it is cold, though its output and efficiency fall as the temperature drops, and it only heats the rooms that have indoor units. Using air conditioning to heat in winter

That is usually a defrost cycle. In cold, damp weather frost builds up on the outdoor unit, and the system pauses heating to melt it, so the indoor fan stops and you may see steam rising from the outdoor unit. It restarts on its own when the defrost is finished. Why the outdoor unit defrosts in cold weather

Yes, while the system is cooling or heating. An open window lets warm or cold air in, so the system works harder and may struggle to hold the temperature. Closing blinds or curtains on sunny windows also cuts the heat it has to remove. Doors, windows and blinds

Yes, and sleep mode is designed for it. It adjusts the temperature gradually through the night and keeps the fan quiet. Aiming the airflow away from the bed avoids a direct draught. Sleep and quiet modes

Use the airflow controls on the remote to aim the louvre up or away from where you sit, or turn swing off once the air is going where you want. Cool air sinks, so aiming it level or slightly up spreads it better when cooling, and warm air rises, so aiming it down works better when heating. Directing the airflow

Start cooling early, before the room heats up, keep blinds and curtains closed on sunny windows, and choose a comfortable setting rather than the lowest. In extreme heat a unit may not bring a sunny room all the way down to the setting. The NHS has advice on staying safe in hot weather. Using air conditioning in a heatwave

Multiply the power the system draws, in kW, by the hours it runs, then by your price per kWh. For example, a unit drawing an average of 0.5 kW for 6 hours uses 3 kWh, which at an example rate of 25p per kWh (check your own tariff) comes to 75p. Real use varies with the weather, the room, the setting and the unit. How much does air conditioning cost to run?

It moves heat rather than making it, so it delivers more cooling or heating than the electricity it uses. In mild weather, small air-to-air systems commonly deliver 3 to 5 kW of heat for each kW of electricity, and less as it gets colder. How much a system uses in total depends on its size, the weather, the setting and how long it runs. COP and EER: what efficiency means

It depends on your electricity and gas prices and on how efficiently the system runs in the weather you are heating in. To compare, divide your electricity price per kWh by the system's COP, and your gas price per kWh by your boiler's efficiency written as a decimal, such as 0.9; each gives a cost per kWh of heat. The answer changes with tariffs and outdoor temperature, so there is no single figure. Heating with air conditioning compared with gas

A kW measures power, the rate at which a system uses electricity or moves heat. A kWh measures energy, the amount used by drawing 1 kW for one hour. Your bill charges per kWh, so running costs depend on both the power drawn and how long it is drawn for. Power and energy: kW and kWh

Choose a comfortable setting rather than an extreme one, keep doors and windows closed and blinds down on sunny windows, clean the filters regularly and keep the outdoor unit clear. A timer or schedule can stop the system running in rooms nobody is using. How to cut running costs

Solar panels can supply some of the electricity it uses. Cooling is a good match, because the sunniest days are when rooms overheat and panels generate the most. Heating is a weaker match, because winter days are short, so much of the electricity for heating comes from the grid. Air conditioning and solar panels

A time-of-use tariff charges different prices at different times of day, often less overnight and more in a late afternoon and early evening peak. It can lower your costs if you can move some running into the cheaper hours, for example by using a timer to cool or warm a room ahead of time. The new rates apply to all your electricity use, not just the air conditioning, so price your whole household's use, standing charges included, before switching. Time-of-use tariffs

A little. Switched off at the remote, a unit stays powered to run its electronics, and some outdoor units also keep the compressor warm in cold weather. The amount is usually small compared with running, and it varies by model. Does air conditioning use a lot of electricity?

Usually every few weeks while the system is in regular use, and more often in a dusty home. With the unit switched off, the filters normally lift or slide out from behind the front panel and can be vacuumed or rinsed in lukewarm water, then left to dry fully before going back in. Check the manual for your model. How to clean the filters

Manufacturers typically recommend regular servicing, often yearly, and some warranties depend on it, so check the terms of yours. A service usually includes cleaning the indoor and outdoor units, clearing the drain and checking the system runs as it should. What a service involves

Common causes include a blocked or kinked condensate drain, a dirty filter, or an indoor unit that isn't level. If it keeps happening, switch the system off and call an engineer, because water can damage walls, floors and anything electrical below. Water dripping from the indoor unit

A thin layer of frost on the outdoor unit is normal when heating in cold, damp weather, and the system clears it with a defrost cycle. Thick ice that stays after a defrost isn't normal and needs an engineer. Ice on the pipes or indoor unit while cooling isn't normal either, so switch cooling off and clean the filters, and call an engineer if it comes back, because it can point to a fan fault or a refrigerant leak. Ice on the pipes or outdoor unit

A musty smell often comes from dirty filters or from dust and moisture building up inside the indoor unit or its drain. Cleaning the filters is the first step, and a service can clean the parts you can't reach. A burning or electrical smell is different, so switch the system off and call an engineer. Musty or unusual smells

A soft rush of air, a steady hum from the outdoor unit, clicks as plastic parts warm and cool, and a brief hiss or gurgle as refrigerant moves or the system switches to defrost are all normal. Grinding, squealing, scraping, banging or loud buzzing aren't, so switch the system off and call an engineer. A rattle can be as simple as a loose panel or something touching the outdoor unit, so check what you can see first. Noises: what's normal and what isn't

Start with the simple checks, which are the mode and set temperature, the filters, doors and windows left open, and anything blocking the indoor or outdoor unit. In very hot or very cold weather a unit may also be working at its limit. If it still struggles, call an engineer, because a refrigerant leak or a fault needs a qualified engineer to find and fix. Not cooling or heating properly

Note the code or the pattern of flashing lights and look it up in the manual, because codes differ between manufacturers. Switching the system off for a few minutes and back on sometimes clears a one-off fault. If the code comes back, call an engineer and tell them what it shows. Error codes and flashing lights

There is no fixed lifespan. It depends on how hard the system works, how well it was installed, how exposed the outdoor unit is and how well it is looked after, and regular filter cleaning and servicing help it last. How long air conditioning lasts

In England, an air source heat pump, including an air-to-air system, can usually be fitted without planning permission under permitted development, as long as the conditions are met. They include limits on the outdoor unit's size and position, the MCS 020(a) noise standard, and a rule that an air-to-air system must not be used solely for cooling. A Lawful Development Certificate from the council gives certainty, and Scotland, Wales and Northern Ireland have their own rules. Do you need planning permission?

Under permitted development in England, a house that isn't detached, such as a semi-detached or terraced house, can have one heat pump, and a detached house can have two. An air source heat pump already on the property, such as one that runs radiators, is likely to count towards that number. The outdoor unit, including any housing, must be no more than 1.5 cubic metres. Where the outdoor unit can go

Under permitted development in England, it can't go on a wall facing a road above the ground floor, and conservation areas and other protected areas have stricter rules on walls and roofs facing a road. It also can't go on a pitched roof, and on a flat roof it must be at least 1 metre from the edge. Anywhere that doesn't meet the conditions needs planning permission. Do you need planning permission?

No longer, in England. The permitted development rule that the unit had to be at least 1 metre from the boundary was removed in 2025. The installation still has to meet the MCS 020(a) noise standard at the neighbours' windows, which can limit where the unit goes. Do you need planning permission?

To count as permitted development in England, the installation must meet the MCS 020(a) standard, which means noise from the outdoor unit must be no more than 37 dB(A) at 1 metre from the nearest window or door of a habitable room in a neighbouring home. The calculation uses the unit's sound power level, nearby hard surfaces, the distance to the window and any barrier. The installer keeps the calculation, and you should get a copy. Noise rules and your neighbours

Possibly, but extra rules apply. A listed building needs listed building consent, and because permitted development doesn't cover listed buildings, planning permission is usually needed as well. In England, conservation areas and other protected areas have stricter permitted development rules, including on walls and roofs facing a road. Talk to your local council before going ahead. Listed buildings and conservation areas

Flats follow different planning rules from houses, so check with your local council whether you need planning permission. If you are a leaseholder, you will usually also need the freeholder's written consent for work such as drilling through an outside wall, and some leases don't allow it at all, so check your lease first. Flats and leasehold homes

You will normally need your landlord's written permission, because a fixed system means drilling through an outside wall and usually adding an electrical circuit. A portable unit usually needs no permission as long as nothing is drilled or fixed to the building, but check your tenancy agreement. Air conditioning in rented homes

Not usually. In Great Britain, mandatory leak checks apply only to systems holding 5 tonnes CO2 equivalent or more. A typical home split, with roughly 0.5–1.5 kg of R32, is far below that, though some larger systems using R410A, such as multi-splits, can reach it. The rules that do apply are that only a suitably qualified engineer may install, service or dismantle a system, and that refrigerant must never be released. F-gas rules for homeowners