Summer under a flight path: keeping cool with the windows shut

In winter, living under a flight path mostly means keeping the windows shut, which you would do anyway. Summer is different. The house heats up, the obvious fix is to open everything, and every open window lets the planes back in. The way through is to keep heat out in the first place, find ways to move air that do not depend on open windows, and save the open windows for the hours when the runway is quiet.

Why summer is harder under a flight path

Three things come together in summer.

The windows are open. A closed window is the main thing standing between you and the noise outside. Open it and most of that protection goes.

There are more flights. Many airports are busiest in summer, and the nights grow even more than the days. From our recordings, Gatwick handled about 830 flights a day in July, with 118 between 23:00 and 07:00. In December and March it was about 660 a day and fewer than 60 a night. Manchester had about 655 a day and 106 a night in July, against 526 and 61 in December. Heathrow, which is capped, changes much less: 1,218 a day in January, 1,315 in August.

The evenings are long. You spend more time in the garden and more evenings with the doors open, just as the airport is at its busiest. The UK even draws its official noise contours from an average of the 92 days of summer.

How much noise gets in: open, closed and vented

The Association of Noise Consultants (ANC) publishes guidance for designing homes where noise, ventilation and overheating pull against each other. Its worked example for a typical small bedroom gives these rough figures for how much quieter it is inside than outside:

Every 10 dB sounds roughly half as loud, so the gap between the first row and the last is large. Real rooms vary, and the ANC notes that an open window lets in more or less depending on which way it faces relative to the noise. A window on the side of the house away from the flight path is the one to open.

Keep the heat out first

The less heat gets in, the less you need to open up.

• Shade the glass during the day. The UK Health Security Agency advises closing blinds and curtains on windows in direct sun.
• Shade from outside if you can. External shutters, external blinds, awnings and overhangs stop the sun before it reaches the glass. England's building rules for new homes count these as ways to limit heat from the sun, but not internal blinds or curtains, because they do less.
• Choose solar control glass if you are replacing windows anyway. The same rules treat glass that lets through less of the sun's heat as a way to limit overheating. Our guide to the best windows for aircraft noise covers the acoustic side.
• Cut the heat you make. Turn off heating, lights and equipment you are not using.

Move air without opening the windows

Trickle vents and acoustic trickle vents

Trickle vents, which the building rules call background ventilators, are the slots in the top of many window frames. They are meant to be left open. In England, replacement windows usually have to include them, unless the house is ventilated another way, such as by MVHR. For new homes near sustained loud noise, the rules call for noise-attenuating vents.

An acoustic trickle vent lets far less noise through than an ordinary one: in the ANC's example, swapping ordinary glazing and vents for acoustic ones takes a room from about 21 dB to about 31 dB quieter than outside. But trickle vents only supply fresh air. The ANC is clear that they do not move enough air to cool a room.

Powered acoustic ventilators

These are fan units fitted through the wall, with a sound-absorbing path for the air. Heathrow's insulation scheme fits powered ventilation units where a home needs them. In the scheme Gatwick put forward for its northern runway, the ventilators cut outside noise by at least 40 dB(A) and can supply at least 170 m³ of air an hour, enough for two air changes an hour in most rooms. Gatwick says they are there so windows can stay shut more often in warm weather, though not so that you never need to open them.

Mechanical ventilation with heat recovery

Mechanical ventilation with heat recovery (MVHR) supplies fresh air to living rooms and bedrooms through ducts and extracts stale air from kitchens and bathrooms, so the house needs no trickle vents. In winter it uses the outgoing air to warm the incoming air. In summer that is the last thing you want, so many systems have a summer bypass that stops the warming. MVHR gives the quietest result in the table above, but it moves fresh air rather than chilling it, and fitting the ducts is usually a job for a new build or a major renovation.

Fans and air conditioning

• Fans cool you, not the room, by moving air over your skin. The UK Health Security Agency advises using them when the air is below 35°C and not pointing them straight at your body. Some people also find a fan's steady hum masks the planes at night; our guide to sleeping under a flight path covers masking sound.
• Portable air conditioners have to vent hot air outside, usually through a hose in a part-open window, which lets noise back in. Seal the gap around the hose as well as you can.
• Fixed air conditioning needs no open window, but costs more to install. England's rules for new homes treat it as the last resort, after shading and ventilation.

Open up when the runway is quiet

The Health Security Agency's advice is to open windows when the air outside is cooler than inside, for example at night. Under a flight path, time it to the airport as well as the temperature.

• Use the quiet hours. At Heathrow a typical night has no landings or take-offs from about 23:30 to 04:35, so there are about five hours to cool the house with the windows wide open. At Gatwick the gap is much shorter, from about 03:00 to 04:45. Our Heathrow page and the other airport pages show the quiet hours, and our guide to what time planes stop flying explains the night rules.
• Use the runway pattern. Planes follow the wind, so on days when they land and take off the other way, your street may be quiet all day. At Heathrow, on westerly days, one runway takes landings until 15:00 and the other after, swapping each week, so a street under one approach gets its landings for only half of each day.
• Close the bedroom window before the first arrivals if they would wake you. Heathrow's first landings come in from 04:30.

New homes: what the rules say

New homes in England built under the rules that took effect in June 2022 have to meet Approved Document O, the building standard on overheating, and it takes noise at night into account. Where noise could be an issue, the design has to assume windows will be shut from 23:00 to 07:00 if bedroom noise with them open would be above 40 dB averaged over the night, or above 55 dB more than 10 times a night. In those places, the bedrooms have to stay cool enough without relying on open windows at night.

Under a flight path, a partly open window can easily let in more than that. If you are buying a new home near an airport, ask the developer how the overheating design works with the bedroom windows shut: shading, acoustic vents, mechanical ventilation or cooling. The rules apply to new homes only.

What insulation schemes include for ventilation and cooling

Several airport schemes now include ventilation, because insulated rooms with the windows shut need another source of fresh air.

Whether you qualify, and what each airport pays for, is covered in our guide to airport noise insulation schemes. If you do, ask for ventilation as part of the survey: acoustic windows are only half the answer if you have to open them every warm night.