Two Horsham houses on the same road can get different quotes for the same unit. That isn’t guesswork. It comes from a handful of things we measure on the survey. This guide goes through them in the order we look at them, so you can work out roughly where your job will land before we visit.
Start with the price band
Our installation prices, all + VAT, are:
- £1,200–£2,200 for a single room split system;
- £2,800–£4,500 for a two-room multi-split;
- £4,500–£8,500 for three to five rooms;
- £8,000–£16,000 for an air-to-water heat pump, before the grant.
Servicing is £95–£150 and a repair visit starts at £75 for diagnosis. Commercial VRF systems are priced after a survey. Every installation price includes the equipment, fitting, commissioning and F-Gas records.
Step 1: size the room, then the unit
We work out the cooling and heating load from the room size, the glazing, which way it faces and how well it is insulated. A loft bedroom with a large roof window needs more capacity than a shaded ground-floor study of the same size. A bigger unit costs more to buy, but an undersized one runs flat out and never quite copes. Our sizing guide explains the sums.
Step 2: find a home for the outdoor unit
A ground-level spot at the back, close to the room, is the cheapest option. Costs rise when the unit has to go high on a wall (brackets and safe access), on a flat roof, or far from the indoor unit. In Horsham town centre and the older streets around it, the position may also be shaped by planning. Horsham District Council has nearly 40 conservation areas across the district, and its published appraisals include the Horsham town centre conservation area as well as London Road, Richmond Road and Park Terrace Gardens.
In a conservation area, the outdoor unit must not go on a wall or roof that faces a road and be treated as permitted development. Listed buildings need separate consent. Our guide to where to put an outdoor unit covers noise and neighbours too.
Want it done properly? AirCon Doctor installs, repairs and services air conditioning and heat pumps across London and the South East, from our base in East Grinstead. We’re an F-Gas certified company and NICEIC approved. Get a fixed-price quote.
Step 3: plan the pipe and drain route
Refrigerant pipes, a power cable and a condensate drain link the two units. A short, straight route through an outside wall is quick. A route through two floors, along a hallway or round a bay window takes longer and uses more trunking. If there’s no way for the condensate to fall to a drain, a small pump is fitted. Older solid walls take longer to core-drill than cavity walls.
Step 4: check the electrics
Each system needs a dedicated circuit. As an NICEIC approved firm we can fit and certify it. If your consumer unit is full or dated, that is the part of a quote that can grow, and we show it as a separate line so you can see it.
Step 5: businesses and offices
For shops, clinics and offices in and around Horsham, we also look at ceiling voids (cassette or ducted units), working hours, landlord consent and whether the total cooling capacity brings TM44 inspections into play. Read our guide to TM44 inspections if you have a larger system. Business prices follow a survey.
Planning, grants and VAT
The Planning Portal sets the national rules: a house can usually have an air source heat pump as permitted development if the outdoor unit is no more than 1.5 m³, it meets MCS 020(a) and it isn’t only for cooling. Air-to-air heat pumps are included since 2025. Cooling-only units and flats need a check with the council.
If your new system replaces fossil-fuel heating and heats the whole house, the Boiler Upgrade Scheme can pay £2,500 towards air-to-air or £7,500 towards air-to-water. There’s an extra £1,500 until March 2027 for air source or ground source heat pumps in homes on oil or LPG with no mains gas, which may suit villages around Horsham. VAT on qualifying heat pumps in homes is 0% until 31 March 2027, then 5% (HMRC Notice 708/6). We confirm the VAT on your quote. This is general information, not tax advice.
For more about the town, see our Horsham air conditioning page and the Horsham area page.
Quick answers
Can you price my Horsham job from photos?
For a simple single room, often yes. Send photos of the room, the outside wall and your consumer unit. Bigger jobs need a site survey.
Why might my neighbour’s quote be lower?
Usually because their outdoor unit sits closer to the room, the pipe route is shorter or their electrics needed less work.
Is the price fixed?
Yes. Once we’ve surveyed, the quote is fixed unless you change the plan.
Do you fit heat pumps in villages around Horsham?
Yes. We’re MCS certified for heat pumps and cover the whole Horsham district.
Related services
More advice
- How to Choose the Right Size Air Conditioning Unit
- Where to Put an Air Conditioning Outdoor Unit
- Air Conditioning Installation Cost: What the Quote Should Include
- Air Conditioning Cost in the Crawley and Gatwick Area: Full 2026 Guide
- All advice
This guide is general information, checked against the sources linked on 30 October 2026. It isn’t legal, tax or financial advice. Rules, grants and product ranges change, so check the current position before you rely on it.