Crawley · cooling guide
How to cool a loft conversion in Crawley
Written by Solomon Amos.
Sources: CIBSE TM59, Building Regs Part O, gov.uk Boiler Upgrade Scheme, and MCS (the certification scheme for registered installers) - see methodology
Last checked against current grant rules on 14 August 2026

Quick answer
Overheating risk for the typical Crawley loft conversion is moderate, so the usual fix is air-to-air heat pump, about £1,900-£2,185 installed. An air-to-air heat pump replacing qualifying fossil-fuel or electric heating can attract a grant through an accredited installer; kept alongside your boiler it is private-pay. Check your address for the exact verdict.
Of Crawley's EPC-certified homes, 257 are loft conversions, rooms carved out in direct contact with the roof. That exposure adds its own overheating factor to the base house type, which is why the loft room so often runs hottest in summer. Cooling it takes more than an open window.
Struggling to keep your Crawley loft conversion cool once the heat sets in? You are far from the first to notice - and although loft conversions are a smaller share of the borough (about 257 homes, 0.6%), they overheat about as reliably as any home type here. On our overheating scale a typical Crawley loft conversion lands near 45 out of 100 - "moderate" - meaning the fan-and-open-window routine stops coping once real heat arrives. This page gives you the property-specific answer instead: which cooling system suits your home, the real cost, and whether planning permission comes into it - before any installer visit.
Why loft conversions in Crawley overheat
A loft conversion sits directly beneath the roof with almost nothing between the plasterboard and the tiles, so it takes the full force of the roof's solar gain in a way the rooms below never do. Worse, the insulation packed in to make the room warm in winter also traps heat in summer, and that penalty stacks on top of whatever the house underneath already contributes. The result is a room that can be pleasant in the morning and genuinely unusable by late afternoon, while the rest of the house stays tolerable. For a single room taking this much direct roof heat, a compact cooling unit sized to that space is usually all it takes, and the rooms below may need nothing at all. For a typical Crawley loft conversion, the median floor area is around 107 sqm - that is what a correctly-sized unit needs to match, on top of the roof exposure already driving the load.
Loft conversions in Crawley: by the numbers
1% of Crawley homes are loft conversions
257 of 44,172
107 m²
median floor area
£792
median annual heating cost
EPC band distribution
257 loft conversions in Crawley with an EPC on record
Greener bands are more energy-efficient; red bands (E-G) are poorer-fabric homes that trap summer heat.
| EPC band | Homes | Share |
|---|---|---|
| A | 0 | 0% |
| B | 8 | 3% |
| C | 95 | 37% |
| D | 102 | 40% |
| E | 42 | 16% |
| F | 6 | 2% |
| G | 4 | 2% |
When these homes were built
Construction era of 255 loft conversions in Crawley
- pre-1919 15%
- 1919-1944 5%
- 1945-1999 62%
- 2000+ 19%
| Era | Homes | Share |
|---|---|---|
| pre-1919 | 37 | 15% |
| 1919-1944 | 12 | 5% |
| 1945-1999 | 157 | 62% |
| 2000+ | 49 | 19% |
Real EPC and property-intelligence data via HomePortfolio, aggregated for loft conversions in Crawley. Data as of 11 July 2026.
Read past the chart to what it implies: the fabric is average, converted stock that holds summer heat about as readily as it lets winter warmth go, and these are mostly post-war stock with moderate mass and modest original insulation, so the heat that gets in does not leave easily. On the environment: air quality (PM2.5) averages about 5.4 µg/m³ and daytime noise around 52 dB, in a borough that is a town that warms markedly in prolonged hot spells, though its evenings cool faster than a big-city core - which is what tells you if free night cooling is realistic. This is historic ground, too: a meaningful minority of these homes sit inside a conservation area and some sit close to a listed building - which is why the planning route for an outdoor unit needs more care here than the approval rate alone suggests. Being near a listed building is not the same as your home being listed.
What the data says about loft conversions in Crawley
Start with what these homes are built from. In Crawley, 40% of these homes carry an EPC band of D. That is middling on the EPC scale, the everyday rating for London's converted and period stock, and it tells you the fabric is doing an average job in both directions. The full spread reads 40% at band D, 37% at band C, 16% at band E, so the picture is a range, not a single rating. At 62%, post-war 1945-1999 stock is the largest block here - middling thermal mass and insulation that was rarely generous to begin with.
Can you cool this home by opening a window at night?
Before you commit to a system, it is worth knowing whether this home can be cooled for free by opening windows overnight. At about 52 dB it is marginal: workable on a side street, awkward near a main road with the windows open overnight. Local PM2.5 air quality, around 5.4 µg/m³, is not the limiting factor.
How the planning numbers look in Crawley
When it comes to permission, only 16 of the 257 loft conversions we profile in Crawley sit inside a conservation area, around 6%, so most homes of this type here are outside one. In conservation areas such as Forestfield and Shrublands and Worth, expect the external siting to draw more scrutiny.
A worked cooling plan for a typical loft conversion
Worked example · a typical loft conversion in Crawley
Recommended system
Air-to-air heat pump
Cools in summer and heats in winter - the only cooling system the £2,500 grant can fund.
Replacing your mains-gas heating with an air-to-air heat pump cools in summer and heats in winter, and qualifies for the £2,500 Boiler Upgrade Scheme grant when installed by an MCS-certified installer.
Boiler Upgrade Scheme
£0 grant - eligible
Eligible: replacing your mains-gas heating with an air-to-air heat pump via an MCS-certified installer qualifies for the £2,500 Boiler Upgrade Scheme grant.
Not claimable yet
The grant itself is law and your eligibility is real, but no air-to-air product has reached the MCS Product Directory yet, so no installer can issue a Boiler Upgrade Scheme voucher today. Air-to-air enters MCS scheme scope on 5 December 2026, and vouchers follow once certified products list. Get quotes now, but treat the grant as pending rather than banked.
- Installed by an MCS-certified installer
- Residential property only
- Existing qualifying heating system is decommissioned, not retained alongside the new system
- Not combined with another government heating grant for the same install
- Air-to-air products must be listed on the MCS Product Directory before a voucher can be issued - not yet the case
Indicative cost
- Typical install
- £1,900–£2,185
- Less grant
- −£2,500
- You pay
- £0
- Indicative UK install cost, sourced from 2026 trade guides - actual quotes vary by property and installer.
- Net cost shown after the £2,500 Boiler Upgrade Scheme grant.
Confirm with your local planning authority
- Whether this property is a listed building materially changes the answer - this was not confirmed.
- External condenser units must meet permitted-development noise limits regardless of planning route.
- This is an indicative assessment only - always confirm the final position with your Local Planning Authority (LPA) before installing.
Illustrative only. Your own floor, aspect, heating and conservation status change the result - check your specific address below.
The right system, and the £2,500 grant honestly

For most Crawley loft conversions, the strongest option is an air-to-air heat pump - a modern high-wall or ceiling unit, the same hardware people loosely call "air conditioning", except it heats as well as cools. It is near-silent, controllable room by room, and because it does both jobs it can replace your existing heating entirely. There are two honest ways this plays out, and which one applies to you turns on a single decision: whether you replace your heating or keep it. For context, a typical Crawley loft conversion runs around 107 sqm and already costs about £792 a year to heat - the baseline the figures below are measured against.
Branch 1 - replace your gas heating, and the £2,500 grant is in play. The £2,500 air-to-air grant (Boiler Upgrade Scheme) only pays when the heat pump replaces your fossil-fuel or electric heating and is fitted by an MCS-certified installer. So if you take out your existing system and let the air-to-air heat pump handle your heating as well as your cooling, a job costing around £1,900-£2,185 installed can come down to roughly £0 net. Eligibility is per-property and depends on your current heating and the installer's accreditation - our checker confirms it against your address. (Grant rules as of August 2026 and subject to change.)
Branch 2 - keep your boiler and simply add cooling, and the grant does not apply. If you want to keep your existing heating and only add cooling, that is a private-pay job - a cooling-only add-on that keeps your boiler is not eligible for the £2,500 grant, whatever your heating type. The sensible choice here is usually a single-split air conditioning unit (around £1,500-£3,000 installed), carried out by an F-Gas / REFCOM-registered engineer - not MCS, which applies only to the grant-eligible heat-pump route above.
We match you to the right accreditation for whichever path fits your home: MCS for the grant-eligible heat pump, F-Gas / REFCOM for a pure cooling install. For a typical loft conversion in Crawley at around 107 sqm, sized to that footprint, our checker leans toward air-to-air heat pump, but your own floor, aspect and heating decision move the answer - which is the whole point of checking your specific address.
What cooling costs in Crawley in 2026
| Air-to-air heat pump | Single-split AC | |
|---|---|---|
| What it does | Cools in summer and heats in winter | Cools only |
| Typical install cost | £1,900 - £2,185 | £1,500 - £3,000 |
| The £2,500 grant | If you replace fossil-fuel or electric heating, via an MCS installer | Not eligible |
| Cost after grant | £0 - £0 (if eligible) | £1,500 - £3,000 |
| Installer accreditation | MCS | F-Gas / REFCOM |
Planning permission in Crawley
Planning permission is more straightforward here than in a lot of the country. Crawley has relatively low conservation-area coverage, so most houses can fit an outdoor condenser under permitted development without a fresh application - flats are still the exception, and a front or side unit there will usually need planning permission from Crawley Council. In Crawley, conservation areas such as Forestfield and Shrublands, Worth and Brighton Road are where this bites hardest. One recent rule change matters here. As of May 2025 an air-to-air heat pump counts as a heat pump for planning, so a house can often install one under permitted development within the size and siting limits - whereas a pure cooling unit, which only cools, still needs a full planning application. Which system fits your home therefore decides which planning route you are on. For a typical loft conversion here, our checker's read is: it depends on details we cannot confirm from public property data - such as conservation-area or listed status - so treat this as indicative and confirm directly with the council. External condenser units must meet permitted-development noise limits regardless of planning route. This is an indicative assessment only - always confirm the final position with your Local Planning Authority (LPA) before installing. Crawley carries genuinely low conservation-area coverage (about 3% of EPC-certified homes), which makes an external unit a lower-friction proposition here than in a heritage-dense borough for most addresses - a real advantage, not a workaround. It is entirely achievable - Crawley Council approves these regularly - yet it remains a step rather than a rubber stamp, and one to pin down for your specific address before committing. Take this as indicative guidance rather than legal advice.
6%
of loft conversions in Crawley sit inside a conservation area
3%
within 30 metres of a listed building
Conservation-area and listed-building status both tighten the planning route for an outdoor unit. Sitting near a listed building does not by itself make a home listed, so the checker confirms your property individually.
Conservation-area and listed-building records © Historic England 2026, via planning.data.gov.uk, used under the Open Government Licence v3.0. Data as of July 2026. See all data sources.
Permitted development, or a planning application?

Air-to-air heat pump (heats and cools)
Can be permitted development
Can be permitted development on a house under Class G, within size, siting and noise limits, because since 29 May 2025 a unit that also heats is no longer excluded for cooling.
Pure air conditioning (cooling only)
Needs planning permission
Not permitted development - a cooling-only condenser fails the Class G "not solely for cooling" condition and there is no other PD class for it, so it needs a full planning application.
| Air-to-air heat pump | Cooling-only AC | |
|---|---|---|
| Does the permitted-development route apply? | Yes on a house, within the Class G limits below (it heats as well as cools). | No - a cooling-only unit needs full planning permission. |
| Property type | Houses get the Class G right directly. For a flat the right sits with the whole building (one unit for the block) and needs freeholder consent, so in practice a flat almost always needs permission. | Planning permission required either way. |
| Maximum outdoor-unit size | Up to 1.5 cubic metres on a house (0.6 cubic metres for a block of flats). | Not applicable - planning permission required. |
| Number of units | Up to two on a detached house; otherwise one. | Not applicable - planning permission required. |
| Where it can go | Not on a pitched roof; on a flat roof it must sit at least 1 metre from the edge; not on a wall above ground-floor level that faces a highway. | Set by the planning application. |
| Conservation area | Stricter - it must not go on any wall or roof that faces a highway, and an Article 4 direction can remove the right entirely. | Planning permission required. |
| Listed building | Excluded from permitted development; listed-building consent is needed regardless. | Excluded from permitted development; listed-building consent is needed regardless. |
| Noise | Must pass the MCS Planning Standards (MCS 020) sound test, measured at the nearest neighbour's door or window. | Any planning permission will set its own noise conditions. |
England only, as of 29 May 2025 (reflects the 29 May 2025 Class G change, SI 2025/560). Sources: GPDO 2015, Schedule 2, Part 14, Class G (air source heat pumps); SI 2025/560 (the 2025 amendment).
This is an indicative summary of England permitted-development rules for outdoor units, not legal advice. Rules change and vary locally - confirm the final position with your Local Planning Authority before installing.
Common questions about cooling a loft conversion
Does a top-floor or loft conversion in Crawley really overheat?
Comfortably, yes. We put a typical Crawley loft conversion near 45 out of 100 on our overheating scale ("moderate"). Crawley holds around 257 homes of this type - 0.6% of the borough's certified stock - and roof heat gain, thin thermal mass in older stock and the local heat-island effect combine to leave homes like this uncomfortable from late June, whatever the thermostat suggests.
What is the best cooling system for a loft conversion in Crawley?
An air-to-air heat pump is usually the best answer for a Crawley loft conversion: one near-silent, room-by-room unit that cools in summer and heats in winter. Prefer to keep your boiler and simply add cooling? A single-split air conditioning unit is the usual private-pay route. For a typical home of this type our checker leans toward air-to-air heat pump, though your floor, aspect and heating decision shift it - which is exactly why checking your own address is worth it. These loft conversions average around 107 sqm. A typical Crawley loft conversion already costs around £792 a year to heat.
Can I get the £2,500 grant for cooling my Crawley home?
Only in one specific case, and it is worth being precise. You are eligible for the £2,500 air-to-air grant (Boiler Upgrade Scheme) only when an air-to-air heat pump replaces your fossil-fuel or electric heating and is fitted by an MCS-certified installer. If you keep your boiler and add cooling as an extra, that is a cooling-only add-on and it is not eligible for the £2,500 grant, whatever your heating type. Eligibility is per-property, so our checker confirms it against your address. (Grant rules as of August 2026 and subject to change.) Given a typical Crawley loft conversion already costs around £792 a year to heat, replacing that heating as part of this route is usually where most of the saving comes from.
Do I need planning permission for air conditioning in Crawley?
Often, yes - more often than for a house. Permitted-development rights that let a house fit an outdoor unit do not apply the same way to flats, and much of Crawley sits inside a conservation area, especially around Forestfield and Shrublands, where an external condenser on a front or side elevation usually needs council permission. It is very doable, but treat it as a step to plan for, not a formality - our checker gives you the likely position for your specific address.
How much does it cost to cool a loft conversion?
As an indicative guide sourced from 2026 UK trade prices: an air-to-air heat pump for this home is around £1,900-£2,185 installed, coming down to roughly £0 net if it replaces your heating and qualifies for the grant. A single-split air conditioning unit that keeps your boiler is around £1,500-£3,000 installed with no grant. Actual quotes vary with access, unit size and pipe runs. A typical Crawley loft conversion currently costs around £792 a year to heat. That heating bill sits alongside the cooling cost above, not instead of it.
MCS or F-Gas - which installer do I actually need?
It depends on the route, and getting it wrong is a common trap. The grant-eligible air-to-air heat pump route needs an MCS-certified installer - that accreditation is what the grant requires. A pure cooling install (a single-split, multi-split, ducted or portable unit that keeps your existing heating) needs an F-Gas / REFCOM-registered engineer, not MCS. We match you to the right accreditation for whichever path fits your home. This is a separate question from planning permission - Crawley Council handles that side, and accreditation is ours to get right.
If I use the checker, will you cold-call me?
No. The free cooling check shows your full plan on screen straightaway, with no phone call and no waiting. If you would like us to email your plan, or to have a single vetted local installer contact you about a survey, you choose that at the end - we only get in touch if you ask, and you are never sold to five companies at once.
What can I do to cool a loft conversion without air conditioning?
Begin with blocking heat: reflective or external blinds on the roof lights, extra shading, and night cross-ventilation where noise permits. Better roof and rafter insulation holds the daytime peak. These help genuinely, but under a roof they usually only blunt the worst of it - which is why plenty of Crawley loft rooms still turn to active cooling.
Does insulation for winter warmth make a loft conversion hotter in summer?
Both directions, yes. Insulation that keeps a loft warm in winter equally slows summer heat leaving, so a well-insulated loft clings to solar heat into the evening. It is still worthwhile for winter bills and the daytime peak, but on its own it will not cool the room in summer.
Will a single split unit cool a loft conversion room effectively?
For one loft room, usually - a properly sized single-split is the standard, effective fix, cooling that space quietly and leaving the rest of the house alone. Sizing to the room's heat load is the key, and a loft's load exceeds its floor area because of roof exposure. The checker estimates the capacity needed.
What size outdoor unit can I fit under permitted development?
It depends on the system. Since 29 May 2025 (SI 2025/560), an air-to-air heat pump - which heats as well as cools - can be permitted development on a house: broadly a unit no larger than 1.5 cubic metres (0.6 cubic metres for a block of flats), and not on a wall above ground-floor level facing a highway, as long as you are not in a conservation area. A pure, cooling-only air conditioning unit does not get that route - it needs a full planning application whatever its size. Flats and conservation areas usually fall outside the permitted-development rights either way, so a unit there typically needs permission. The checker applies this to your address. In Crawley, that conservation-area exclusion bites hardest around places like Forestfield and Shrublands.
Does the air-to-air grant still apply if I add air conditioning but keep my gas boiler?
No. You are eligible for the £2,500 air-to-air grant (Boiler Upgrade Scheme) only when an air-to-air heat pump replaces your fossil-fuel or electric heating and is fitted by an MCS-certified installer. If you keep your boiler and add cooling as an extra, that cooling-only add-on is not eligible for the £2,500 grant, whatever your heating type - it is an F-Gas / REFCOM job instead. (Grant rules as of August 2026 and subject to change.) Given a typical Crawley loft conversion already costs around £792 a year to heat, that saving is only available on the replace-your-heating route above.
Check your own Crawley home
Pre-scoped to a loft conversion - enter your address for a plan specific to your property.
- Address
- Confirm
- Questions
- Plan
Let's look at your home
We use property data to pre-fill the boring bits - no long forms, and we never cold-call you.
Every home is different - your floor, aspect, EPC, heating type and conservation status all move the answer. Our free cooling checker pre-fills your home from public property data (EPC and UPRN records) and gives you a property-specific verdict on screen, straightaway: your overheating score, the right system, your real grant eligibility, the planning position and a net cost. No phone call, no waiting.
Check my Crawley homeYou will see your full cooling plan instantly. If you would like us to email it to you, or to have a single vetted local installer contact you about a free survey, you choose that at the end - we only get in touch if you ask.
Every figure above - overheating scores, costs, grant rules and planning positions - follows our published methodology.
