Air conditioning for Dartford homes and businesses, fitted to cool and to heat
Installation, servicing and repairs across Dartford and the DA postcodes, from new-build flats at Ebbsfleet to interwar semis in Wilmington and shop floors on the High Street. Nearly every unit we fit is reversible: the room it cools in August it warms in January. Leave a postcode and we ring you back.
Get a price
Three details and we call you back with the next step.
- A survey before any price
- New-build covenants checked first
- Cooling and heating from one unit
How warm is Dartford, month by month?
Twelve tide boards, one a month, each filled to the average afternoon temperature at Greenwich Observatory, the Met Office climate station nearest to Dartford. A red board is a month when a reversible unit spends most of its time cooling; a blue board is one when it mostly heats.
- Afternoon peak averages 8 Celsius; the unit mostly heats.January
- Afternoon peak averages 9 Celsius; the unit mostly heats.February
- Afternoon peak averages 12 Celsius; the unit mostly heats.March
- Afternoon peak averages 15 Celsius; the unit mostly heats.April
- Afternoon peak averages 19 Celsius.May
- Afternoon peak averages 21 Celsius; the unit mostly cools.June
- Afternoon peak averages 24 Celsius; the unit mostly cools.July
- Afternoon peak averages 23 Celsius; the unit mostly cools.August
- Afternoon peak averages 20 Celsius.September
- Afternoon peak averages 16 Celsius; the unit mostly heats.October
- Afternoon peak averages 12 Celsius; the unit mostly heats.November
- Afternoon peak averages 9 Celsius; the unit mostly heats.December
Mean daily maximum in °C, 1991 to 2020. Greenwich is ten miles up the river and inside London's heat island, so Dartford itself probably runs a shade cooler, but it is the closest station the Met Office publishes, and the shape of the year is the same: a July high near 24°C, about 23 nights of air frost a year, and under 570 mm of rain. Source: Met Office.
Why does Dartford need more cooling every year?
Because it is growing faster than almost anywhere in England, and the new homes are the ones that overheat. Between the 2011 and 2021 censuses Dartford's population rose from about 97,400 to about 116,800, a jump of 20.0% that only Tower Hamlets beat among English councils. Much of that is the Ebbsfleet Garden City: the Development Corporation set up in 2015 passed its 5,000th home in December 2025 and counted 5,319 by April 2026, with up to 15,000 planned, and the borough's plan adopted in April 2024 allows for thousands more up to 2037.
A home built since the 1990s is airtight by design, often single-aspect, and very often has a south- or west-facing glass wall. Building Regulations only started asking new homes to limit overheating from 15 June 2022, through Approved Document O, and that document covers new residential buildings alone. Everything finished before then, and every conversion since, was signed off without an overheating check. That is why a two-year-old flat at Castle Hill can be harder to sleep in than a Victorian terrace on East Hill, and why so many of our first calls come from estates that did not exist ten years ago. Sources: ONS; Ebbsfleet Development Corporation; EDC annual report 2026; Dartford Borough Council; Planning Portal; Elmhurst Energy.
Who owns the wall the outdoor unit goes on?
That is the first thing we work out, because the answer decides whether the job is a survey or a planning application. The 2021 Census counted 45,696 households in the borough: 14,398 in semi-detached houses, 14,103 in terraces, 6,025 in detached houses and 9,762 in purpose-built flats, with 812 in houses split into flats and 243 above shops or in other commercial buildings. Permitted development allows a semi or a terrace one outdoor unit, a detached house two, and a block one for the entire building, provided the block is nothing but flats.
Renting is the other half of the question. Private renting in Dartford rose from 15.9% of households in 2011 to 18.1% in 2021, and no tenant should let a bracket touch the wall without the landlord's consent in writing. A leaseholder needs the freeholder's. On the newer estates there is a third party too: a management company whose covenants may say where plant can and cannot go. We ask about all of them before we measure a room. Sources: Census 2021; ONS; Planning Portal; LEASE.
What changes inside Dartford's six conservation areas?
The position of the outdoor unit. Dartford Borough Council has six conservation areas: Dartford Town Centre, designated on 31 October 1980 and the largest in the borough, Greenhithe from October 1975, Southfleet from March 1970, Hook Green, Church Hill in Wilmington and Red Street in Southfleet, the last two added in September 1998. Inside each of them, the permitted development right excludes any wall or roof fronting a highway and any spot nearer the road than the house, which is why we walk round to the garden first. The town centre area runs the length of the High Street and takes in more than 30 listed buildings, among them Holy Trinity church at Grade I, listed in 1953.
Older Article 4 directions sit on top. The national register lists five in the borough, among them one over the Greenhithe conservation area since March 1984 and two on West Hill: Hampden Place, 73 to 87, from September 1980, and 31 to 35 from October 1983. Elsewhere in the borough the single restriction on walls is that a road-facing wall may carry a unit only at ground-floor level. Sources: Dartford Borough Council; appraisals page; planning.data.gov.uk; HeritageCheck; Historic England; Article 4 directions; Planning Portal.
How hot does this corner of Kent get?
Hotter than most of the country. On 10 August 2003 the Met Office station at Gravesend-Broadness, on the Swanscombe peninsula a few miles east of Dartford, recorded 38.1°C and was briefly the hottest place in British records, until a reading of 38.5°C from Brogdale near Faversham was confirmed. The Broadness station closed in August 2018, which is why the chart above uses Greenwich, but the heat has not moved: summer 2026 was provisionally ranked the UK's hottest on record by the Met Office, averaging 16.5°C across the season and peaking at 38.1°C at Kew on 13 August.
Nights decide whether people ring us. Government research found that above 26°C a bedroom stops giving a proper night's sleep, and that more than half of households sometimes report barriers to opening their windows, mainly noise and security. Beside the A282, under the Crossing's approach roads or on a main road through Stone, that is most summer nights. Our home air conditioning page starts with the bedroom. Sources: KentOnline; Met Office on 2003; ITV News, reporting the Met Office; MHCLG.
Homes, new and old
Begin with the room you give up on in a heatwave. Around Dartford that is usually a new flat with a glass wall and no cross-draught, a back bedroom in a 1930s semi, a loft room, or a conservatory nobody sits in after midday.
Air conditioning installation
The whole job from the first measurement to the handover of the remote, with every consent checked on the way.
Home air conditioning
The back bedroom, the new flat with the glass wall, the loft nobody can sleep in: cooled in summer, warmed in winter.
Air-to-air heat pumps
The same wall unit, run the other way: a room heated for pence an hour, with the summer cooling thrown in.
Multi-split air conditioning
Several rooms, one box in the garden. The design that fits inside a semi's single permitted outdoor unit.
Conservatory air conditioning
For the glass room that is a greenhouse in July and a fridge in January, and the garden office beside it.
Workplaces and premises
Dartford's own J & E Hall, founded in the town in 1785, went on to make refrigerating machinery, and today the town's working buildings run from the shops and offices of the centre to the depots along the A282. Any room with people, screens, ovens or servers in it runs hot by June.
Office air conditioning
Offices from a room above a shop to a floor on a business park, with the heat rules and the landlord dealt with.
Commercial air conditioning
Retail and hospitality premises, sized with the door open and the bedroom over the shop remembered.
Server room cooling
Dedicated cooling for the rack, calculated from the wattage on the plugs and running when the office is dark.
Looking after a system
If a system is already on the wall, we maintain and mend it, whichever firm put it there. If you are still deciding, begin with the cost guide.
Can the same unit heat the room in winter?
Yes, and far more cheaply than a plug-in heater. With the cycle reversed, the outdoor unit draws warmth out of the winter air, frost included, and the indoor unit gives it to the room. According to the Energy Saving Trust, air-to-air heating typically achieves a seasonal efficiency above 4: each kilowatt-hour of electricity becomes roughly four kilowatt-hours of heat. Under Ofgem's October to December 2026 cap of 26.32p per kWh, a kilowatt-hour of warmth therefore costs about 6.6p, where a fan heater charges the full 26.32p and gas costs 7.97p before the boiler wastes any.
What it heats is the air in the room it serves, not the radiators and not the hot water tank. The biggest winners are the 3,830 Dartford households heated by electricity alone. See air-to-air heat pumps. Sources: Energy Saving Trust; Ofgem; Census 2021.
What about shops, offices and the units along the A282?
Dartford knows a thing or two about cooling: J & E Hall, founded in the town in 1785, moved from heavy engineering into refrigerating machinery. Today's working buildings are more varied: the High Street and the Priory Centre, offices on the business parks near the Crossing, the warehouses and depots along the A282, and the workplaces that will follow the Lower Thames Crossing, which won its planning consent on 25 March 2025.
Employers must keep indoor temperatures reasonable, though no legal maximum exists, and in June 2026 the Health and Safety Executive stated that heat is a workplace hazard requiring assessment like any other. Where the cooling in a building exceeds 12kW in total there is a further obligation: an energy inspection no less than once every five years. See offices, shops, salons and restaurants and server rooms. Sources: Wikipedia; National Highways; legislation.gov.uk; HSE; GOV.UK.
What should you ask any installer for before you pay?
Three pieces of paper. First, the firm's F-gas company certificate: every business that handles refrigerant in equipment it does not own, down to a one-man band, has to hold one from an approved body and renew it every three years, and the individual engineer who breaks into the circuit needs his own qualification besides. Second, the name of the registered electrician who will sign the Part P certificate, since a new circuit in a dwelling is notifiable work. Third, the noise calculation at the closest neighbouring window, which has to show 37 dB(A) or below before the job qualifies as permitted development.
We hand over all three without being asked, and the F-gas guide shows how to verify what any installer tells you. Sources: GOV.UK on companies; GOV.UK on qualifications; IET; Grant UK.
Which towns do we cover?
Dartford and the DA postcodes first, then over the Bexley border and down the A20. Every town page deals with that place on its own terms: how its homes were built, what its council has designated and which walls an outdoor unit may use.
Air conditioning in Bexleyheath
Air conditioning in Bexley
Air conditioning in Welling
Air conditioning in Sidcup
Air conditioning in Gravesend
Air conditioning in Swanley
Air conditioning in Wilmington
Also on our round
- Dartford town centre, West Hill, East Hill and Temple Hill (DA1)
- Joyce Green, The Brent and Fleet Downs (DA1, DA2)
- Stone, Greenhithe and Bean (DA2, DA9)
- Swanscombe, Ebbsfleet and Castle Hill (DA10)
- Darenth, Sutton-at-Hone and Hawley (DA2, DA4)
- Longfield, New Barn and Hartley (DA3)
- Crayford and Barnes Cray (DA1)
- Erith, Slade Green and Belvedere (DA8, DA17)
- Eynsford, Farningham and New Ash Green (DA4, DA3)
From first call to first cool night
Tell us about the room
A call to 01322 952910 or the form with your postcode in it. Which room overheats, what the building is, and whether the outside wall is yours to drill.
Survey, then a figure in writing
We measure the room, choose a position for the outdoor unit, calculate the sound at the neighbour's window, look inside the consumer unit and ask about leases, landlords and covenants. The price arrives in writing with the electrics itemised.
Consents settled first
If a freeholder, landlord, management company or council has a say, we wait for it, and we supply the drawings and sound figures they will ask for.
Installed, tested, shown to you
Units, pipes and the new circuit are fitted; the pipework is pressure tested and evacuated before charging; the system runs in both modes while we measure it; the certificates are yours and so is a tour of the remote. After that, a service once a year.
Read these before you ask for prices
What does air conditioning cost to fit and to run?
Where the money goes: the unit, the labour, the wiring, the electricity, and the extras a flat or a new estate brings.
Air conditioning and planning permission: the rules for England
Every permitted development condition in one table, then the twists Dartford's new estates and conservation areas add.
Air conditioning with no outdoor unit: how monoblocs work
The through-the-wall units for flats and blocks that cannot take an outdoor box.
Air conditioning in a flat: who has to agree, and in what order
Lease, freeholder, management company and planning, in the order to tackle them.
Bedroom air conditioning: what it does for sleep, and what it costs
The sleep threshold, noise at night, sizing and the price of a quiet bedroom.
Cooling a loft conversion: the options that work
Why lofts cook, the free fixes first, then where a unit goes on a dormer.
What size of air conditioner does a room need?
Kilowatts and BTU by room size, with the adjustments that matter.
How to check an air conditioning installer on the F-gas register
The company certificate, the engineer's category and where to look them up.
Portable or fixed air conditioning: which is right for you?
Price, power, noise and running cost, and when a portable is the right call.
What people in Dartford ask us
Roughly what does a wall unit cost fitted in Dartford?
Our figure comes after a survey, not over the phone. As a national yardstick, Checkatrade lists £750 for a 12,000 BTU wall unit and £1,150 for fitting it; added together that is about £1,900, with £400 to £700 on top for the electrics. What pushes it up or down is in the cost guide.
We live on a new estate with a management company. Does that complicate things?
Sometimes. Read the covenants before the survey: certain estates control what may be fixed to the outside of a house, and the original planning permission may carry a condition that removed permitted development rights. We look into both before quoting.
Is air conditioning possible in a flat?
Frequently, provided the freeholder consents in writing and the block has not already used its single permitted outdoor unit. Where a neighbour got there first, or nothing is allowed outside, the alternative is a monobloc fed through two wall grilles.
Will it warm the room in winter too?
A reversible unit will, for roughly a quarter of what a plug-in electric heater costs to run. It warms the room it hangs in; the radiators and the hot water stay with the boiler.
What will the neighbours hear?
Very little. To qualify as permitted development the calculated sound at their nearest window must be 37 dB(A) or below, which is quieter than a fridge. We run that calculation before quoting and give you the number.
Which towns do you cover?
The borough of Dartford, the Bexley side from Crayford round to Sidcup, Gravesend and Northfleet, and Swanley. Every place, with its postcode and council, is on the areas page.
Want us to ring you?
A name, a number and a postcode is enough. Say which room if you can. Or ring 01322 952910.