Does an EPC tell me if a home overheats in summer?

No. The A to G rating measures how well a home retains heat and what it costs to run, which makes it a winter measure. The calculation behind it includes an overheating check, but that doesn’t affect the rating you see and isn’t shown to buyers of existing homes. It says nothing about damp or drainage either.

Are recent heatwaves a one-off or a trend?

The Met Office data points to a trend. Summer 2026 was provisionally the UK’s warmest on record, 2025 was its warmest year, and hot days and warm nights have risen sharply over recent decades.

Will this winter be extreme too?

No forecast can say this far out. The Met Office signal for a strong El Niño points to a milder, wetter and windier autumn and early winter for the UK, with colder spells more likely late in the season. UK winters are trending wetter rather than colder, though a mild average still leaves room for a hard cold snap.

Do I need permission to install air conditioning?

Often, yes. An external unit can need planning permission, especially in a conservation area or on a listed building. In a leasehold flat you’ll usually need the freeholder’s written consent, and some leases prohibit outside alterations.

Does my conveyancer check flood risk?

Yes. Flood risk and drainage are covered by the standard searches, and enquiries can cover any history of flooding, damp or insurance claims. Lenders and insurers will take a view on what comes back.

Can a heatwave or drought affect my purchase?

It can. Long dry spells shrink clay soil, the most common cause of subsidence in England and Wales. The environmental search checks ground stability, and enquiries cover any history of cracking or underpinning. Remedial work may be required or the cost to fix may prove a deterrent.

From 38°C to downpours: what weather extremes mean for home buyers

15 Sept 2026 7 minutes read

Market updates

Key takeaways

Home efficiency is being judged on two seasons now: summer comfort as well as winter warmth.

The UK has just had its warmest summer on record, and its winters are getting wetter rather than colder.

An Energy Performance Certificate (EPC) mainly estimates how much energy, and therefore money, it should take to heat a home in colder weather.

Air conditioning often needs planning permission or freeholder consent, so it’s a legal question as well as a purchase.

Drought raises subsidence risk and wet winters raise flood and damp risk. Both show up in your conveyancer’s searches.

From unprecedented summer sun to a wet winter ahead

2026 British weather has run from one extreme to the other, and it started wet. Seven named storms crossed the UK by late January. Storms Ingrid and Chandra flooded around 400 homes in England, while Wales saw widespread flooding, with Monmouth and Carmarthenshire among the worst hit. England ended the season with its eighth wettest winter since 1836.

Then came the heat. The Met Office has confirmed summer 2026 as provisionally the UK’s warmest on record, at a mean 16.5°C, 0.4°C above the 2025 record. Temperatures peaked at 38.1°C, and the heat from 30 June to 5 August lasted 37 days.

For years, the energy question from buyers was simple: how warm will this home be in winter, and what will it cost to heat? Recent summers have added a second. How cool will it be in Summer, and can I fit air conditioning? Rightmove research backs this up:

Searches for homes with air conditioning are up 104% on last summer
87% say a home’s ability to stay cool matters when choosing their next home
Only 11% think their current home stays comfortable in hot weather.

A year of extremes

A single season is easy to dismiss as a blip. The longer-term data says otherwise, in both directions. 2025 was the UK’s warmest year on record, and days above 30°C and nights above 18°C have more than quadrupled in Greater London over the last decade, compared with 1961 to 1990.

Winters are moving too, but towards water rather than cold. The winter half-year across 2016 to 2025 was 13% wetter than 1961 to 1990, and days of air frost are down by around a quarter. The bills follow the water: insurers paid £6.1 billion on weather-related property damage in 2025, and the average homeowner flood payout rose 60% to £30,000.

Nobody can predict in September exactly what the winter will do. The Met Office has confirmed a strong El Niño, which for the UK raises the odds of a milder, wetter and windier autumn and early winter, with colder spells more likely later on.

That changes what buyers are looking for. Shade, orientation and cross-ventilation now sit alongside insulation and boiler age, while gutters, drainage and damp are moving from maintenance jobs to pre-offer questions.

An Energy Performance Certificate (EPC) tells you half the story

An EPC measures how well a home holds heat in, and what it costs to run. The methodology includes an overheating check, but it doesn’t feed the A to G rating and isn’t shown to buyers of existing homes. Nothing on the certificate covers damp, drainage or flood risk either.

The government is overhauling the system. In January it confirmed that EPCs will drop the single A to G letter for four measures: fabric, heating, smart readiness and energy cost. But the new certificates haven’t arrived, the launch has slipped to the second half of 2027, and even then, they won’t score summer overheating. New builds are the exception: homes built under the rules introduced in June 2022 must limit overheating by design.

A sinking feeling: the rising risk of subsidence

Subsidence claims in the UK surged 140% year-on-year in August 2026 after consecutive record-hot summers. The average claim hit a record £20,000 between April and June, with insurers paying out £72 million against £60 million a year earlier.

Hot, dry weather draws moisture out of clay-rich soil, causing it to shrink and the ground beneath a house's foundations to drop away. That shrinkage is rarely even. It's worse near thirsty trees, or where a house sits across two soil types, so one part of the building settles more than another and the structure cracks.

This is where surveys come in. A lender's valuation won't tell you anything about movement, so you may choose to commission your own. An RICS Level 2 covers most homes, while a Level 3 goes into more detail on older properties, anything near large trees, or where you've already spotted possible movement. Separately, the environmental search your solicitor runs after an offer is accepted includes a ground stability rating drawn from British Geological Survey data.

What to check at a viewing: summer versus winter

The same features have impacts across seasons, they just work in opposite directions. Whichever season you view in, here's what to look for.

Spring/Summer

Autumn/Winter

Orientation and glazing

Afternoon sun through south and west-facing glass. Look for blinds, shutters or an overhang to control it.

The same glass loses heat fast. Check for draughts, condensation between panes, and failed seals.

Insulation

Keeps heat out, but holds it overnight if the home cannot vent. Top-floor rooms show this first.

The main driver of the EPC rating and heating costs. Look for cold spots on walls and gaps around windows.

Ventilation

Windows that open on two sides, and safely at night. Check whether air moves through the home.

Look for trickle vents and extractor fans. Also check for mould around window reveals or in bathroom.

Roof space

Rooms under the roof bake. Check for vents at the eaves and whether the loft has any airflow.

Insulation depth, and daylight, staining or damp on the underside of the roof.

Trees and ground

Real shade, and how much of the garden gets sun. Overhanging branches near the roof and gutters.

Leaf fall blocking gutters, and ground that stays saturated between rain.

Water

Supply, pressure, and whether the area sees hosepipe restrictions.

Gutters and gullies running in rain. Damp patches and tide marks on external walls.

Subsidence

Peak season for cracks to open. Diagonal cracks at window and door frames, sticking doors, sloping floors.

Clay swells back as it rehydrates, so cracks can close and hide. Ask about past claims, and look for fresh filler or recently painted walls.

Selling in Autumn? Here's a viewing ready checklist

Autumn is a useful preparation window. For homeowners and sellers, now’s the time to:

Check for damp, mould and condensation, particularly around windows and in colder rooms.
Inspect window and door seals and replace any that are cracked or failing.
Check external walls and brickwork for cracks or areas where water could get in.
Clear drains and grates so autumn leaves don't cause blockages.
Check trees and overhanging branches near the property, especially before winter storms.
Check the roof and flashing (the waterproof material around joints and chimneys that prevents rainwater entering your home) while it is dry.
Watch where downpipes discharge in heavy rain.
Test the heating system and make sure radiators are working properly.
Check the boiler service record, if applicable.
Check loft insulation is adequate and hasn't been disturbed or compressed.
Check external taps and pipework before freezing weather arrives.
Take care of garden maintenance while conditions are still favourable.

If you are buying in Autumn, that list becomes your questions for the seller, and the searches pick up the rest.

Considerations and searches

An outside air conditioning unit can need planning permission, and conservation areas, listed buildings and flats are treated more strictly. In a leasehold flat the freeholder must consent in writing. If the seller has already fitted one, we ask for the paperwork, as we do for solar panels, loft conversions and extensions. The local authority search shows what the council holds on record, so we can see what was approved and what was not.

Water cuts both ways. Long dry spells shrink clay soil, the most common cause of subsidence claims in England and Wales, while wet winters bring surface water, overloaded drains and damp. Two searches answer for that, and a third follows if either flags a problem:

The environmental search screens flood risk, contaminated land and ground stability.
The drainage and water search shows where public sewers run and whether rainwater drains to a sewer or to a soakaway, which is a private pit you maintain yourself.
Where flood risk shows up, a full flood report splits it into river, coastal, surface water and groundwater.

A flood result rarely stops a purchase, but it changes the terms. Lenders can ask to see that insurance is available before releasing funds, and premiums and excesses climb with the risk. Flood Re, the scheme that keeps cover affordable in high-risk areas, only backs homes built before January 2009.

The seller's property information form asks about flooding directly, and we follow up on cracking, underpinning, damp and past claims.

Where Eden fits in

Use the EPC for what it covers, running costs and winter warmth. At your viewing look for summer heat and winter cold and rain performance, and ask the right question at the viewing. Then let us handle the legal side and more complex searches. We’ll flag any risks, so you always know where you stand and be fully informed before you move in.

Frequently asked questions

No. The A to G rating measures how well a home retains heat and what it costs to run, which makes it a winter measure. The calculation behind it includes an overheating check, but that doesn’t affect the rating you see and isn’t shown to buyers of existing homes. It says nothing about damp or drainage either.
The Met Office data points to a trend. Summer 2026 was provisionally the UK’s warmest on record, 2025 was its warmest year, and hot days and warm nights have risen sharply over recent decades.
No forecast can say this far out. The Met Office signal for a strong El Niño points to a milder, wetter and windier autumn and early winter for the UK, with colder spells more likely late in the season. UK winters are trending wetter rather than colder, though a mild average still leaves room for a hard cold snap.
Often, yes. An external unit can need planning permission, especially in a conservation area or on a listed building. In a leasehold flat you’ll usually need the freeholder’s written consent, and some leases prohibit outside alterations.
Yes. Flood risk and drainage are covered by the standard searches, and enquiries can cover any history of flooding, damp or insurance claims. Lenders and insurers will take a view on what comes back.
It can. Long dry spells shrink clay soil, the most common cause of subsidence in England and Wales. The environmental search checks ground stability, and enquiries cover any history of cracking or underpinning. Remedial work may be required or the cost to fix may prove a deterrent.