How to check aircraft noise before buying a house

Most people who end up unhappy under a flight path did check. They stood in the garden on a viewing, heard a plane or two, and decided it was fine. The trouble is that a single visit samples one day, and at most airports one day tells you almost nothing.

Why one viewing is not enough

Planes take off and land into the wind. When the wind changes, the airport turns its traffic around: the planes that came in low over one side of the airport now come in over the other, and the take-offs swap sides too.

That makes the same street loud on some days and quiet on others. Two of our sample reports show how big the gap can be:

"Loud" here means above 65 dB outdoors, about the level of a loud conversation. If you viewed either house on a quiet day, you would have heard almost nothing.

1. Find the runway lines

Start with a map. Find the airport's runways and extend each one in a straight line in both directions. Landing planes line up on that line 15 km (about 10 miles) or more before touchdown and descend along it, so every house on or near it hears them at the same height every time.

The height is predictable. A normal approach descends at 3 degrees, which is about 170 ft for every kilometre (300 ft for every nautical mile). At Heathrow, landing planes are around 400 ft above the ground 2 km before the runway, 1,400 ft at 8 km and 2,700 ft at 15 km. At those heights a large jet is loud well to either side of the line.

Take-offs are different. They climb steeply and then turn onto a few set routes, so the houses under the first few kilometres beyond the runway end get the most, and the rest depends on which routes are in use.

2. Check how often each direction is used

Now find out how often the airport uses each direction. At most airports one direction dominates because of the prevailing wind. In north-west Europe that is usually the west: at Heathrow planes land towards the west on about six days in ten.

So a house under the approach from the east is in the path most of the year, and a house under the approach from the west gets planes on the remaining days. Some airports also have runways that are only used for landings or only for take-offs, or rules that favour one runway at night. Our airport pages give the split for each airport, measured from a year of flights.

3. Count the night flights

Night flights matter far more than their number suggests. The World Health Organization's guidelines for Europe recommend keeping aircraft noise below 40 dB Lnight at night, the level at which about one person in ten is highly disturbed in their sleep, and below 45 dB Lden over the whole day. Both are well below the levels most airports use to decide who gets help with insulation.

Look for three things:

• How many flights there are between 23:00 and 07:00 on an average night, and on the busiest nights.
• When the first flights arrive. At many large airports the first landings come in before 5 a.m.
• Any night rules. Some airports have curfews or quotas, others fly through the night, especially cargo hubs.

4. Read the official noise map, and know its limits

Most large airports publish noise contour maps, and in Europe governments must publish strategic noise maps for every airport with more than 50,000 flights a year, every five years. The UK draws its contours as an average over the summer day (LAeq,16h) and treats 51 dB as the lowest level of concern. In the US, the FAA uses a day-night average of 65 dB (DNL) as the level where homes are considered significantly affected.

These maps are worth checking, but they have limits:

• They are averages. A day with 100 loud planes and a day with none average out to 50 moderate ones, which nobody hears.
• They are drawn in broad bands, at levels where many people are already bothered. The FAA's national survey, published in 2021, found about two in three people highly annoyed at 65 dB DNL, where the older curve behind that threshold predicted about one in eight. A 2023–24 survey for the UK's Civil Aviation Authority found one person in ten highly annoyed at about 43 dB, well below the UK's 51 dB.
• They are often years old. Traffic, runway use and flight paths change between editions.

Use the map to rule places in or out, then count the loud flights for the address itself.

5. Watch real days, in both directions

Flight trackers show you where planes fly. Live trackers only show today, so they have the same problem as a viewing. Better options:

• The airport's own flight tracker. Many airports run WebTrak, which replays recent days with flight heights and sometimes noise readings.
• Our free flight map, which replays a whole day of landings and take-offs in a minute. Pick a typical day in each runway direction and the busiest night, then tap the street to see how many loud planes it heard.

6. Visit at the right time

If you visit, choose the moment the house is most exposed:

• Check the wind forecast. Planes land into the wind, so pick a day when the wind blows from the direction that sends them over the house.
• Go early or late. The first wave of arrivals between 6 and 7 a.m. and the evening peak are when you will hear the most.
• Stand where you would sleep and sit. Listen from the bedroom with the window open, and from the garden.

7. Ask the right questions

Ask the seller or agent, and if you can, the neighbours:

• Have they complained to the airport about noise, or been in a dispute about it?
• Has the house had a noise insulation grant or an offer from the airport? That means it is inside an official contour.
• What windows does it have, and which way do the bedrooms face?
• Are there plans for a new runway, more flights or new flight paths? Check the airport's consultations and the local council's planning pages.

Don't rely on the paperwork to raise it. In England, the seller's property information form asks about disputes and complaints concerning the property or a property nearby, but has no question about aircraft noise as such.

8. Get the figures for the exact address

All of these checks add up to one question: how many loud planes will you hear at this address, by day and at night, and on the bad days as well as the good ones? A Flight Noise report answers it from a full year of recorded flights over the exact spot you pin, with a real day of each kind replayed plane by plane.

Checklist