How to soundproof your home against aircraft noise

Most soundproofing advice is written for road traffic or noisy neighbours. Aircraft noise is different in two ways that change where the money should go: it arrives from above, and much of it is a low rumble that ordinary walls and windows let through.

Why aircraft noise is hard to keep out

It comes from above. Traffic noise hits one side of a house. A plane overhead hits the roof, and it meets the walls and windows at a glancing angle, which is when a façade blocks the least sound. Research by Canada's National Research Council notes that this alone can noticeably weaken a façade directly under an approach path. Rooms under a roof or loft are noisier than rooms with another floor above them, and rooms with sloping or vaulted ceilings are noisier still.

It is mostly low-pitched. Airliners are loudest at roughly 50 to 400 Hz, the range of a deep roar. Walls and glass stop high-pitched sound far better than low, so indoors the whine of a jet can disappear while the roar is barely reduced. Ordinary double glazing has a weak spot in exactly this range, which is why new windows often disappoint.

It comes in bursts. Each plane is a separate event that builds, peaks and fades, and it is the peaks that stop a conversation or wake you. Insulation will not make the planes inaudible. What it can do is keep them from interrupting you.

The weak points, in order

Sound takes the easiest way in, so a house is only as quiet as its weakest part. The US guidelines for insulating homes near airports put it simply: strong windows next to a weak door let the noise in anyway. Deal with the weak points roughly in this order.

The "points" are on the US STC scale, which gives similar numbers to the European Rw. Each 10 points more means the noise that gets through sounds about half as loud.

Windows

With everything shut, the windows are usually where most of the noise gets in, and better windows do more than any other single change. Against aircraft, the best option is usually secondary glazing: a second window inside the first, with a gap of 100 mm or more. Acoustic replacement windows with thick, laminated panes come next. Our guide to the best windows for aircraft noise explains the ratings and what to ask for.

Ventilation

Insulation only works with the windows shut. With them open, even a well-insulated house cuts outside noise by only about 15 dB. Each room therefore needs fresh air another way: acoustic trickle vents, a quiet single-room ventilation unit, or whole-house mechanical ventilation with heat recovery. A typical trickle vent blocks about 31 dB, an acoustic one about 44 dB, according to the UK acoustics and ventilation design guide.

In England, the building regulations guidance says that if you replace windows that had trickle vents, the new ones should have vents at least as large, and if the old ones had none, the ventilation must not end up worse than before. Ask for acoustic vents rather than leaving them out.

External doors

Doors let in about as much noise as windows. The US guidelines put standard front doors at 21 to 27 points and acoustic doors at 29 to 43. Cheaper routes are a heavier door with compression seals on all four sides, or a second door such as a closed porch. The same guidelines treat letterboxes and cat flaps as holes to be closed.

Roof and loft

Loft insulation absorbs sound inside the roof space; it does not block it. Blocking it takes weight in the ceiling and no leaks: a sealed loft hatch, no gaps around recessed lights, and a second pane under any roof window. Our guide to loft and roof insulation covers this in detail.

Walls, chimneys and other holes

Brick, block and concrete walls rarely need work. Timber-framed or clad walls may need an extra lining. An open chimney is a hole in the roof: a damper or a tight-fitting fireplace door closes it. Through-wall extractor fans and air-conditioning units are holes too.

How much quieter can a house get?

• A typical house with the windows and doors shut cuts outside noise by 20 to 30 dB, according to US guidance, and a well-insulated one by 30 to 35 dB, a little less against the deep noise of airliners. More than 35 to 40 dB is rarely practical in a home.
• Improvements are measured in a few decibels. US airport programmes count a 5 dB improvement as significant and aim for an average indoor level below 45 dB DNL. A 10 dB drop sounds about half as loud.
• The windows have to stay shut. That makes ventilation part of the job, and summer the hardest season.

Which rooms to soundproof first

You do not have to treat the whole house. Start where the noise costs you most:

• Bedrooms, if there are flights late at night or early in the morning. See soundproofing a bedroom against night flights.
• Rooms facing the flight path. The house itself shields the far side: when planes only pass on one side, rooms on the other can be up to 10 dB quieter.
• Top-floor rooms, which have only a ceiling and a loft between them and the plane.

Know your noise before you spend

How much to spend depends on how many loud planes you get, when, and from which direction. A house with a few loud flights at midday needs less than one with loud arrivals before 6 a.m. Official noise maps give an average; they do not tell you how many planes pass at night or which side of the house they pass on.

What airport insulation schemes pay for

Many airports pay for insulation in the homes most exposed to their noise. What they include is a good guide to what works.

• Heathrow: its Residential Insulation Scheme funds up to 100% of eligible work, up to £34,000 a home, for around 20,000 homes, with a first phase from 2025 to 2028. The work comes from a free survey and can include replacement windows or secondary glazing, external doors, acoustically rated ventilation, acoustic quilts in the loft and upgraded ceilings. Conservatories are excluded. See our Heathrow page.
• Germany: airports must refund insulation work for homes in the inner day zone and the night zone of their legal noise area, up to €150 per square metre of living space. In the night zone this covers bedrooms, ventilation units included.
• United States: airports can use FAA grants for homes inside the 65 dB DNL contour whose rooms are at 45 dB DNL or more with the windows shut.

Who qualifies and how to apply are covered in our guide to airport noise insulation schemes.

Get advice, and check for grants first

• Ask the airport before you start. Schemes such as Heathrow's fund the work their own surveyor recommends. Heathrow's covers like-for-like work and charges you only if you choose a higher specification, and it also takes into account work done under earlier schemes.
• Get the noise measured if you are paying yourself. An acoustic consultant can measure the noise, find the weak points and specify products. In the UK, the Association of Noise Consultants lists member firms by region.
• Check the rules. Replacement windows must meet building regulations, including the trickle vent rule above. If the house is listed or in a conservation area, ask the council before changing windows or doors. Heathrow's scheme includes listed buildings but leaves any planning costs with the owner.