Mosquito Net for the Bed, or Screens on the Windows?

A bed net protects whoever is inside it, while they are inside it. That is a real strength at night: a well-hung net with no holes, tucked under the mattress, puts a barrier between a sleeper and every mosquito in the room. It is also its limit. The moment you get up for water, sit at the desk or settle a baby in a cot, you are outside the protected zone, and the room around you may be full of insects that came in through an open window at dusk.

Screens work the other way round. They stop insects entering the room at all, so the whole space is protected for everyone, at every hour, without anyone having to remember to tuck anything in. The NCVBDC's vector control compendium describes house screening as a physical barrier that should be placed on all openings, including windows, doors and eaves, and notes that closing holes and filling crevices also reduces the places mosquitoes can enter and rest. A screen on one window and a gap above the door gives far less than the screen suggests.

Timing matters as well. Because Aedes mosquitoes bite during the day, a bed net used only at night does little against dengue for an adult who is up and about in daylight. Screened rooms help in the daytime too, provided the doors are kept closed or screened.

Air-conditioned bedrooms are not exempt. A room kept closed for the AC still lets mosquitoes in every time the balcony door is opened for a minute or a window is cracked to clear the air in the morning, and once inside they rest in the cool, dark corners behind curtains and under furniture. A screen on the balcony door means the room can be aired without letting in the evening's insects, and it makes the choice between air conditioning and an open window a matter of comfort rather than of bites.

On a still monsoon night the question is not only insects but air. A bed net is a fine mesh drawn closely around the bed, and the closer and finer it is, the more it slows the air reaching the sleeper. Under a ceiling fan most of the breeze still gets through, but on a night when the fan is the only relief, many people find a net stuffy, and a stuffy net is a net that gets pushed aside at two in the morning.

A screened room keeps the windows open and the cross-breeze moving through the whole space. Insect mesh does take some air and some light, and a finer mesh takes more, but the room as a whole stays ventilated. For people who sleep with windows open rather than air conditioning, and in Goa that is a lot of households for much of the year, screens are usually the more comfortable answer.

The exception is a room that cannot be screened properly: an old house with louvred ventilators high in the wall, gaps around timber frames, or a door that has to stay open to the courtyard. There a bed net closes the gap the building leaves. A larger box-shaped net that hangs well clear of the sleeper, rather than a small cone draped close to the face, keeps more of the air.

Babies and small children are where bed nets earn their place. The NCVBDC's vector control guidance specifically recommends bed nets for sleeping infants and young children during the day, and its compendium notes that treated nets, though of limited use against dengue in general because the vector bites by day, can protect infants and night workers who sleep in daytime. A net over the cot at nap time protects the child even if a door is opened for a moment. Keep the net taut and well away from the child's reach, and never let loose fabric hang into the cot.

Elderly parents are a different case. Getting out from under a tucked-in net to reach the bathroom at night, perhaps half-asleep, is awkward and can cause a stumble. For an older person, a well-screened bedroom is usually safer and easier than a bed net. If a net is used, choose one with a wide opening that hangs from a frame, not one that has to be untucked from all sides.

Guests are the third group. Visitors unused to sleeping under nets often leave them half-tucked or knot them up out of the way. In a guest room or a homestay, screens that are simply there, closed at dusk by whoever cleans the room, give more reliable protection than a net that depends on the guest. Our homestay mosquito net page covers that use, and the kids' room page covers screening for children's rooms.

Bed nets come in a few basic shapes, and the bed and the ceiling decide which one works. A conical or bell net hangs from a single hook above the centre of the bed and spreads down over the mattress. It suits a single bed or a small double, is quick to put up, and folds away into a knot by day. On a wide double bed the sides come too close to the sleepers, and a mosquito can bite through mesh that rests against an arm or a shoulder.

A rectangular box net hangs from four corner points, either hooks in the ceiling or cords strung between the walls, and gives a roomier, square space. It is the better mosquito net for a double bed and for anyone who finds a cone claustrophobic. A freestanding frame net carries its own poles, so it needs no ceiling fixings, which helps on a high timber ceiling or in a rented flat. A four-poster or canopy bed is the easiest of all: the net drapes over the frame the bed already has.

Whatever the shape, size it to the bed with enough length to tuck well under the mattress all round, and check it for holes every few weeks, because a single tear lets in exactly the insect you were trying to stop. Keep nets clear of candles, mosquito coils and lamps. In areas with high malaria risk, insecticide-treated nets are distributed under the national programme; follow the instructions that come with them.

For the openings themselves, there are four main systems, and the window decides between them. A sliding window net runs in its own track beside sliding glass, and is the everyday answer for aluminium and uPVC windows. A pleated net folds into a slim side post and suits French windows and wide doors where you want the opening clear by day. Hinged and fixed frames suit casements and ventilators that are never used for access, and magnetic mesh is a stopgap for a single problem window.

In a bedroom, screen every opening that is ever opened, not only the main window: the balcony door, the bathroom ventilator and the gap above an old door all count. The mosquito net chooser shows each system on a typical Goan opening, and our guide to sliding door nets covers bedroom balcony doors in detail.

The monsoon is when the two approaches work best together. Rain fills every container left outside, and mosquito numbers rise. The WHO's dengue guidance combines several layers: clothes that cover the arms and legs, window screens, nets for those sleeping in the day, repellents, and covering, emptying and cleaning water storage containers every week. The NCVBDC's own advice is to remove water from coolers and small containers at least once a week, to use nets or repellents while sleeping in the daytime, and to keep children out of shorts and short sleeves.

In practice that means screens on the bedroom windows and doors as the base layer for everyone, a net over the cot for a baby's daytime sleep, and a net over the bed for anyone working nights or recovering from illness during the day. Add the household routine that no screen replaces: empty plant saucers, check the air-conditioner drip tray and the sunshade drains, and keep stored water covered.

Screens are best fitted before the rains, in April or May, when installers are not working around downpours. If your bedroom windows are not yet screened, our bedroom mosquito nets page explains the options, and the sliding window nets page is where to ask for a measure.