What are the disadvantages of fly screens? The honest verdict (and how to avoid them)
Camille VidalIn short: fly screens have real disadvantages, but fewer than people think. The seven that come up most often: they filter a little light, slow the airflow slightly, need a wipe-down two or three times a season, don't stop the very smallest insects, need accurate measurements, wear out if the mesh is cheap, and can get in the way when the model is fixed. On a made-to-measure magnetic fly screen, four of those seven points all but disappear, and the other three take a few minutes to sort out. Here is the honest verdict, with the figures, and what fixes each one.
We'll tell you everything, including what product pages prefer to leave out. A fly screen is still the simplest, most natural way to sleep with the window open without a single bite, but it's worth knowing what you're signing up for.
The 7 disadvantages of a fly screen, at a glance
Before the detail, the table that sums it all up: each disadvantage, whether it's real or overstated, and what lets you avoid it.
| Disadvantage | Real? | What fixes it |
|---|---|---|
| Less light and view | Slight | A fine black mesh: around 90 to 95% see-through |
| Less airflow | Slight | An 18 × 16 mesh keeps around 65% of the airflow |
| Cleaning | Real, but quick | A damp sponge, two or three times a season |
| Incomplete protection | Real for tiny insects | An edge-to-edge fit, with no gap around the frame |
| Measuring and fitting | Real if you rush it | Three measurements per side, a drill-free fit in 10 minutes |
| Wear: wind, sun, pets | Real on cheap kits | PVC-coated fibreglass, UV-treated, rated for 8 to 20 years |
| Getting in the way, looks | Real on a fixed model | A magnetic closure that shuts itself, a colour that matches |
1. It filters a little light and view
This is the most quoted disadvantage, and the most misunderstood. Yes, a mesh stretched across an opening holds back some light. But how much depends almost entirely on two things: how fine the weave is, and the colour of the mesh.
Why black mesh is the most see-through
It sounds backwards, yet it's simple physics: black absorbs light instead of bouncing it back at you. Your eye looks through the weave rather than at it. A white mesh reflects light and shows up far more, a bit like a net curtain. On our screens, the black mesh keeps around 90 to 95% of the view outside, light grey 75 to 85%, and white 60 to 75%. In a room that gets little direct sun, or one that's already on the dark side, the colour choice matters more than anything else.
What the fineness of the weave changes
An 18 × 16 threads-per-inch mesh leaves around 59% of its surface completely open. The rest is threads of 0.02 mm. From two metres away the weave becomes almost invisible and the room keeps its brightness. The thick mesh of cheap kits, woven more coarsely, is what genuinely "darkens" a room: that's where the bad reputation comes from.
2. It slows the airflow slightly
Second complaint: "with a fly screen, the room doesn't ventilate any more". In reality, an 18 × 16 mesh keeps close to 65% of the airflow of a free opening. That's not nothing, but the comparison that matters is elsewhere: a window open with a fly screen airs a room infinitely better than a window kept shut to avoid being bitten. That is precisely the problem it solves on summer nights.
The only case where ventilation genuinely drops is a clogged mesh: dust and pollen block the openings over the weeks. We come back to that just below, because it's a thirty-second job.
3. It needs cleaning
A fly screen is a filter. So besides mosquitoes, it catches what floats in the air: dust, pollen, the odd insect. Left alone all summer, it goes grey, breathes less well and ends up smelling musty.
What that really involves
On a PVC-coated fibreglass mesh, a damp sponge or cloth is enough, two or three times a season. The coating stops dirt working its way into the thread. What to avoid: the washing machine and abrasive products, which attack the coating and slacken the mesh. A magnetic model has a clear advantage here: it comes off in a few seconds, rinses flat in the shower, and goes back up just as fast. The details are in our guide to maintaining and repairing a fly screen.
4. It doesn't stop everything
Here is the point where honesty matters: a fly screen is a physical barrier, not a bubble. Three limits exist.
- Tiny insects. An 18 × 16 mesh has openings of roughly 1.1 to 1.5 mm. It blocks mosquitoes (tiger mosquitoes included), flies, wasps, hornets and moths. The very smallest midges and thrips can get through. For those you need a much finer mesh, which costs you light and air, and which most homes don't need.
- Crawling insects. An ant or a spider will get under a badly fitted door, fly screen or not. That's a threshold problem, not a mesh problem.
- The ones already inside. A fly screen fitted mid-season doesn't chase out the mosquitoes that came in the month before, nor the ones that come up through an extractor duct or a dry drain. If you have them while everything is shut, read why there are mosquitoes in your home with the windows closed.
The real weak spot: the edges
What lets mosquitoes through is almost never the mesh. It's the gap between the mesh and the frame: a standard model that's too small, a strip that has come unstuck in a corner, a bottom edge that gapes. A mosquito needs two millimetres. Hence the case for made-to-measure: a screen made to the exact dimensions of the opening, fixed all the way round, leaves no way in. That's the difference between "fewer mosquitoes" and "zero bites".
5. It needs accurate measurements
A badly measured fly screen is the classic case of a product "that doesn't work": too small, it leaves a gap; too big, it creases and comes unstuck. The good news is that a tape measure and five minutes settle it.
The method that avoids the mistake
- Measure the width and height in three places (top, middle, bottom; left, centre, right) and keep the smallest value: openings are never perfectly square.
- Work out where the strip will sit: on the frame, inside the reveal or on the wall around it. That choice decides which margins to add.
- Let the configurator do the maths: it adds the fixing allowance itself, according to the model and where you measured.
It's all illustrated, step by step, in our measuring guide. Fitting takes about ten minutes with no drilling and no tools: the mistakes that make an adhesive strip peel are covered in our article on drill-free fly screens.
6. It ages: wind, sun, claws
This is where the price difference shows most. A cheap mesh, in thin polyester or plastic, slackens in the sun, yellows, and tears at the first gust or the first paw. Its lifespan is around two or three seasons.
What makes a mesh last
PVC-coated E-glass fibreglass doesn't rust, doesn't hold creases and doesn't warp. UV-treated, it holds up over time, in rain and by the sea, and is rated for 8 to 20 years depending on use. Its weight, 122 g/m², is that of a proper mesh, not a voile. Its M2 fire rating (the French classification) means it's flame-retardant, which counts for a kitchen door or a barbecue on the terrace.
Wind and pets
On a large, exposed opening, the problem isn't the mesh but the sail effect: a big soft surface catches the wind and pulls on its fixings. The answer is to split the surface with magnetic separations, as on our large fly screens for patio doors. As for cats and dogs, a fibreglass mesh takes a paw without tearing, but a cat that climbs will eventually mark it: we explain what genuinely resists in our guide to fly screens and pets.
7. It can get in the way, and it shows
The last complaint is the everyday one. A fixed fly screen on a door is a door you can no longer walk through freely: you have to unhook it, roll it up, or go round another way. With your arms full, a dog wanting out, kids in and out twenty times, it's taken down within a week.
The magnetic closure changes everything
On a magnetic fly screen door, you walk straight through without using your hands: the two panels part and close again by themselves behind you. The cat learns in a day. It's the only solution that genuinely suits an opening you go through ten times a day.
Looks
A fine weave, in a colour that matches the frame (black, light grey or white), fades into the background. What shows is the aluminium profile of fixed frames and the cassette of roller screens. A soft mesh with no frame, fitted around the outside of the opening, stays the most discreet, and it comes off in thirty seconds for the winter months if you'd rather have a bare window back.
See our made-to-measure fly screens
The disadvantages by type of fly screen
Not every model has the same flaws. Here is where each family falls short, and where it shines.
| Type | Its disadvantages | Its strong point |
|---|---|---|
| Fixed frame (joinery) | Drilling, professional fitting, visible profiles, not removable, high cost | Very sturdy once fitted |
| Roller screen | Visible cassette, mechanism that wears and jams, usually drilled, price | Disappears when not in use |
| Pleated | Fragile mesh, floor rails that collect dust, high price | Minimal bulk when folded |
| Standard adhesive kit | Fixed sizes, gap around the frame, thin mesh that slackens, lasts a season | Very low purchase price |
| Made-to-measure magnetic | You have to measure properly; the mesh is still visible up close | Drill-free, edge to edge, removable, free passage |
To go further on each system, our article on the different types of fly screen details their uses, and our buyer's guide helps you decide according to your opening.
And the advantages, in all this?
Because an honest verdict reads both ways. A fly screen is the only protection that's 100% mechanical: no insecticide, no plug-in, no diffuser, nothing to breathe in for you, your children or your pets. It lets you sleep with the window open on hot nights, which cools the house without air conditioning. And it stops the tiger mosquito, whose bites are no longer just a nuisance. Set against that, filtering 5 to 10% of the light and running a sponge over it three times a summer doesn't weigh much.
How to keep these disadvantages to a minimum
If you only remember five rules:
- Choose a black mesh if light and view matter; white only if you're after privacy.
- Go made-to-measure as soon as the opening isn't a common size: it's the gap around the frame that lets mosquitoes in, not the mesh.
- Prefer a magnetic closure on any door you use often.
- Measure in three places and keep the smallest value.
- Clean with a sponge two or three times a season, never in the machine.
On budget, a made-to-measure window or door fly screen starts at around £30 in the UK, A$60 in Australia and €30 in Ireland, and a large opening from about £100 / A$200 / €100 depending on size, delivery included, with a discount from the second screen. The detail by type of opening is in our price guide.
Frequently asked questions
Does a fly screen really darken the room?
Slightly. A fine 18 × 16 mesh leaves around 59% of its surface open, and a black mesh keeps 90 to 95% of the view outside. It's white or coarsely woven meshes that genuinely darken a room.
Can mosquitoes get through a fly screen?
Not through an 18 × 16 mesh in good condition: its 1.1 to 1.5 mm openings block mosquitoes, tiger mosquitoes included. They do get through around the edges, when the screen is too small or badly fixed. Only tiny insects such as midges cross the mesh itself.
Does a fly screen stop the air circulating?
It slows part of it: around 65% of the airflow is kept on an 18 × 16 mesh. A window open with a fly screen airs a room far better than a closed window, which is the real alternative on summer evenings.
Black or white fly screen: which has the fewest disadvantages?
Black. It absorbs light instead of reflecting it, which makes it almost invisible and keeps 90 to 95% of the view. White shows up more and lets through 60 to 75% of the view, but gives more privacy from outside.
Should I take my fly screen down in winter?
You don't have to: a coated fibreglass mesh copes with rain and frost. Many people take it down to get a bare window back and clean it before storing it flat. On a magnetic model, it takes thirty seconds each way.
Are magnetic fly screens any good?
Yes, provided they're made to the size of the opening and fixed all the way round. The ones that disappoint are the one-size curtain kits held by a few adhesive pads: they gape at the edges and sag within a season. A made-to-measure magnetic screen on a proper adhesive strip holds edge to edge and closes itself behind you.
Which fly screen has the fewest disadvantages?
For most homes, a made-to-measure magnetic fly screen: drill-free, fitted edge to edge, removable in seconds and hands-free on a door. Its only prerequisite is taking accurate measurements.
Find yours in 2 minutes
Measure your opening, choose the mesh colour and the type of fixing, and see your price to the centimetre: configure your made-to-measure fly screen →
Further reading
Also read: Fly screens and pets: what genuinely resists