A condensate pump lifts water from the indoor unit when there is no gravity fall to a waste. The pump itself is the small part of the bill. On a straightforward 2026 install it is often a low-hundreds addition, including fitting, a short discharge and a basic alarm. Long lifts through finished rooms, a concealed route, or a second visit because the first quote forgot the drain, move that addition upward. Pumps fail. The cost of a stained ceiling can dwarf the pump. Survey the fall first. An F-gas certified company is still required for the refrigerant side. The installer who plans the overflow is the one to hire.
Gravity when the pipe can fall
Cooling mode pulls water out of the air at the coil. That water has to leave. A continuous fall to an outside drip or a trapped waste is the quiet, cheap route. If the indoor unit is below the drain, in a basement, in an internal room, or on a wall that cannot drip on a path, you need a pump. Gravity is cheaper and more reliable when a fall exists. Do not accept a hose into a bucket, a slow leak into a plant pot, or a hole that dribbles down a neighbour's brickwork. Those are not designs. They are callbacks.
A low-hundreds extra, unless the building is the work
Equipment-only prices look trivial beside a split. Installed, with a proper discharge, power and a float or alarm, a simple pump is commonly a low-hundreds extra on a job that is already open. Routing a discharge across a listed hall, up two storeys, or through a landlord's ceiling void can push the drain package into the high hundreds because the labour is the building, not the plastic pump. A quote that is silent on condensate is not comparable with one that includes a pump. The cheaper paper may be the one that leaves you with a bucket. Make both quotes name the method. The refrigerant circuit is untouched by a pump replacement in many cases, but the original install still needed a company certified under the GOV.UK F-gas rules. Electrics for the pump should be part of the certified installation, not a trailing plug across a wet floor.
Frequently asked questions
How much extra is a condensate pump?
Often a low-hundreds addition on a straightforward 2026 install. Long or hidden discharge routes cost more because of the building work.
Are pumps reliable?
They are a wearing part. They are fine when they are accessible, alarmed and cleaned. They are a leak when they are forgotten in a ceiling.
Can I avoid a pump by drilling a small drip hole?
Only if the water falls legally and does not stain a wall, a path or a neighbour. The survey should choose a proper termination.
Which rooms usually cannot use gravity?
Basements, internal rooms and many shops need a lift. So does any indoor unit that sits below the only waste, or on a wall that cannot drip on a path.
What if the pump stops over a finished ceiling?
Water can overflow and stain the ceiling. Specify an alarm or a safe overflow. Ask where the water goes if the pump stops. A stained ceiling can cost more than the pump.
Why do bedroom pumps get complained about?
Pumps tick. In a bedroom or a hotel room that tick is a complaint, so place the pump where the sound is tolerable and serviceable. Annual service should include the reservoir. Slime blocks small pumps. A pump left for five years will block.
Core buying guides
Start with these high-intent guides, then dig into the rest of the library.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.