Questions we get asked

No. The survey is free, the written quotation is free, and there is nothing to pay if you decide not to go ahead. If the survey shows the work is not viable at your property, we tell you and there is still nothing to pay.

Surveys are usually within 48 hours in north London. Installation lead time moves with the season: two to three weeks through winter and spring, and considerably longer from the first heatwave onwards, because the whole trade fills up in the same fortnight.

If you already know you want it for summer, booking in March or April is the difference between a date you choose and a date you accept.

We will give you a realistic range over the phone, and the calculator on the cost page will get you close on your own. What we will not do is give a fixed price without seeing the property, because the three things that move the number most are the outdoor unit position, the pipe route and the state of the consumer unit, and none of those can be assessed down a phone line.

Yes. We can invoice a managing agent directly, provide method statements and risk assessments, work to a building's own permit system, and produce the licence pack a freeholder asks for before consenting to an installation.

Ask for the compliance pack when you first get in touch and it saves a round of emails.

We would rather not, and it is worth being clear about why rather than just refusing. If we did not supply it we cannot register the manufacturer warranty in your name, we have no route to replace it if it arrives faulty, and if it fails in year two you are between two companies who each blame the other.

The saving is usually smaller than people expect, because our trade price on the equipment is not far off the retail price you would pay.

Someone needs to let us in and be there at the end for the handover and the certificates. In between, most customers get on with their day. We are not going to need the whole house, just the room, the route and access to the consumer unit.

Less than you would think, and it is contained. Dust sheets go down, the core drill runs with a vacuum on it, and the debris from a 65mm hole fits in a cup. The one genuinely dusty moment is the core coming through the outside wall, and that lands outside.

A cooling unit pulls a litre or two of water out of the air on a humid day, and that condensate has to fall the whole way to somewhere it can drain: an outside gully, a soakaway or a soil stack. Where there is no natural fall we fit a small pump.

A condensate run with a low point in it is the single most common cause of water appearing on a wall two summers later, so we set it out properly rather than following the shortest line.

Often, yes. It can run inside a cupboard, through a void, behind a boxed corner or under floorboards on the way to the outdoor unit. It costs more and it has to be planned on the survey rather than decided on the day, because once the unit is on the wall the route is fixed.

On the outside, the standard finish is white trunking. It can be painted to match the brick or render and most people stop noticing it within a week.

We stop and tell you before doing anything about it. A concealed cable in the wall line, a consumer unit with no spare way, a cavity that turns out to be filled: all of those change the job, and all of them get a price and a decision from you before any more work happens.

What does not happen is a bigger invoice at the end than the one you agreed.

A modern wall unit runs at about 19 to 24 decibels on its lowest fan setting, which is quieter than a fridge and below the level most people can hear over ambient room noise. It gets louder as the fan speeds up, so a unit sized correctly for the room is also the quieter unit, because it spends most of its time on low.

For a bedroom, sound pressure at minimum fan speed matters more than anything else on the specification sheet, and it is the number we compare when we recommend a model.

It removes moisture as a side effect of cooling, which in a British summer is usually the point: humidity is what makes a warm night unbearable. It does not dry a room to the level people associate with air conditioning in a hotel or an office, because those systems run far harder.

If anything, the complaint we get is the opposite: an oversized unit that cools fast, cuts out and leaves the room cold and clammy because it never ran long enough to dehumidify.

Yes, and it takes five minutes. Open the front, slide the filters out, wash them in warm water, dry them fully and put them back. Once a month through the season is plenty.

A blocked filter costs 15 to 25 percent in efficiency and is the most common reason a system that was fine last year is not cooling this year.

A well installed, serviced split system runs 12 to 15 years, and plenty run longer. What kills them early is almost never the unit: it is moisture left in the pipework at commissioning, a slow refrigerant leak from a badly made flare, or years without a service.

That is why the commissioning record matters. It is evidence the system started its life properly.

Nothing, if you are going to use it for heating. If you are not, run it in heating mode for twenty minutes once during the winter. It circulates the oil, keeps the seals from drying and takes almost no electricity.

Do not cover the outdoor unit. Covers trap moisture against the coil and cause more corrosion than the weather does.

Not at present. Several national installers do, and if spreading the cost is what decides it, that is worth knowing before you spend time with us. We would rather say so now than at the end of a survey.

A deposit on booking to secure the equipment and the date, with the balance on completion. The exact figure is on your quotation. We do not ask for the full amount up front and we do not ask for payment for work that has not happened.

Honestly, not in the way a loft conversion does, and any installer who tells you it pays for itself on resale is guessing. What it demonstrably does is make specific rooms usable: a south facing bedroom, a loft conversion, a home office under a flat roof.

The two places it does show up commercially are lettings, where a cooled flat lets faster in summer, and home offices, where people who work from home rate it highly.

It should not, and in our experience it does not. It is a permanently installed appliance on a dedicated circuit with an electrical certificate. Tell your insurer you have had it fitted, as you would with any material alteration, and keep the certificate with your policy documents.

An electrical installation or minor works certificate for the new circuit, the commissioning record with the weighed refrigerant charge and the pressure test result, the manufacturer warranty registration in your name, and the F-Gas record for the system.

Keep all four. Every warranty claim asks for the commissioning record and most homeowners cannot find one.