Are Mosquito Repellent Coils Effective?

By: Peter
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Mosquito repellent coils are they effective?

When it comes to repelling mosquitoes, some people have their own methods that they swear by, while for others, the same techniques are useless.

One such method is burning coffee grounds. I’ve tried it, and the results weren’t conclusive. Perhaps it helped, but I wasn’t sure.

Mosquito repellent coils are another method that involves burning but do they work? Most research suggests they can help with repelling mosquitoes. Let’s take a deeper look.

What Are Mosquito Repellent Coils?

mosquito repellent coil
mosquito repellent coil

A mosquito repellent coil is a spiral of a product that contains an insecticide or repellent. The product vaporizes when the coil is lit. The coil is made of a material that burns slowly, emitting the insecticide or repellent as it burns.

The coils can be suspended in the air or placed in a holder. This enables the coil to get enough air and to burn safely. Mosquito coils may contain either pyrethroid insecticides or plant-derived substances such as citronella. In India, there are even coils made with cow dung and herbs!

A Little History

Mosquito coils were invented in Japan at the end of the 19th century. The original coils used the flower heads from Aster plants (Tanacetum cinerariifolium). They were dried and ground into a powder.

The flower powder was mixed with a starch base to create sticks that would repel mosquitoes and other insects when burnt. As the sticks burned too quickly, they made longer sticks and coiled them into spirals.

The natural insecticide in some members of the Aster family of plants is pyrethrum. Its active ingredient is pyrethrin. Pyrethrins attack the nervous systems of mosquitoes. When present in amounts less than those fatal to insects, they still appear to have an insect-repellent effect. 

Coils are still extensively used in Asia, Africa, and South America, where malaria is present. For example, in Ghana, it’s estimated that 40% of the population uses mosquito coils. To be more effective, the coils are usually used indoors.

How To Use Repellent Coils

A mosquito coil is very easy to use. Attach the center of the coil to the stand that often comes with the coil. Then ignite the outer end of the spiral. The coil will slowly consume, giving off smoke and an odor that will repel mosquitoes.

If the mozzies get too close and if the coil contains an insecticide, it can kill them. On the other hand, if the coil contains aromatic substances, it will repel the mosquito. Repellent coils can last from 4 to 12 hours.

The coils should only be utilized outside and shouldn’t be used near or on something inflammable.

Do Mosquito Coils Work?

The big question is, are mosquito-repellent coils effective? The American Mosquito Control Association says they do provide some protection. They are most effective when there is little wind, so the repellent stays in place.

Although the use of coils inside homes is not recommended, the Malaria Journal published results of tests carried out in experimental chambers, representing local rooms and conditions where malaria is prevalent.

They found that 5 different coils containing pyrethroids resulted in a mosquito mortality rate of between 24% and 64%. The conclusion was that “the coil yielded limited protection as a mosquito avoidance method.”

There seems to be enough evidence to show that burning repellent coils will provide some limited protection when used outdoors. Although they are used inside homes in some parts of the world, where malaria is present, this isn’t recommended. Even the protection when coils are burnt inside houses is insufficient.

My Experience

I have tried mosquito coils on several occasions and have found they do help to keep mosquitoes away.

However, the protection they provide is limited. For example when a coil was placed on a table outside I was bitten on the ankle. Or when the coil was placed under the table to protect our feet, the mozzies bit my arms.

Using several coils at the same time, placed under and on the table did help, but some mosquitoes still managed to find us!

Are They Safe?

Mosquito coils are safe if used outside in well-ventilated areas. However, there has been research that shows if used indoors, exposure to the smoke from mosquito coils could cause health risks. The coils tested produced the same amount of fine particles as burning 75-137 cigarettes and the same amount of formaldehyde as burning 51 cigarettes.

For protection inside buildings better to use methods that don’t emit particles and other chemicals.

Mosquito repelling coils will help to reduce the number of mosquitoes. However, if you are in an area where there is a risk of disease, you need to stop all mosquito bites. Therefore, you will need some other form of protection.

Alternatives To Mosquito Repellent Coils

Mosquito Control

The first place to start is to eliminate any standing water in your yard. This could be in containers, birdbaths, plant pot saucers, blocked gutters, old tires, or children’s pools. Anything that has water added frequently should be emptied at least once a week.

Rainwater barrels or any other container that can’t be emptied should be covered. Ponds or untreated pools should have dunks and/or fish added to them.

Misting systems or fogging can effectively reduce mosquito populations. Spraying insecticides into the environment may harm other insects, so they should only be used when really needed.


You can apply DEET, picaridin, oil of lemon eucalyptus, or other EPA-registered repellents to your skin not covered by clothes. Thermacell devices can be used to create mosquito-free zones.

Cover Up

Wear long-sleeved shirts, trousers, socks, and even netting for your head. You can also wear repellent-treated clothing. Treat any uncovered area with repellent, and pay special attention to your feet and ankles. Some mosquitoes prefer this area of your body.

Mosquito Traps and Bug Zappers

Buy a carbon dioxide mosquito trap. These require ongoing maintenance and expense. They can catch many mosquitoes, but you will probably need other protection forms as they won’t eliminate all mosquitoes.

Other traps may just use UV lights but their success in trapping mosquitos is limited.

Bugzappers may kill a few mosquitoes but will kill many other insects, a great number of which might be beneficial insects. You will need other protection to escape mosquito bites.

Sterile Mosquitoes

It is possible to buy a plan to release sterile male mosquitoes on your property. The males carry naturally occurring bacteria. They mate with females but no eggs hatch. This method will reduce mosquito numbers over time but will not eliminate all mosquitoes.

Electric Fan

Strategically placed electric fans can keep your deck mosquito-free. They work in a few ways. Mosquitoes are weak fliers, so they won’t be able to navigate properly in turbulent air. The fans will also perturb the flow of carbon dioxide you exhale, making it more difficult for the mosquitoes to find you. Additionally, the fans will keep you cool, so you won’t give off as much heat and sweaty odors that help the mosquitoes to home in on us.

Keep Mosquitoes Out of Your House

You shouldn’t use a mosquito coil inside your house. So try to keep the mosquitoes out. Keep the windows and door shut when possible and install screens where necessary. If they do get in, you could consider mosquito traps that use UV light and a special coating to create CO2, plug-in devices, or aerosol sprays.

Summing Up

Repellents, traps, and sprays can reduce the number of mosquitoes and the risk of being infected with the diseases they transmit. The reduction of these pests is best achieved by using an integrated approach. This could be a community-wide program or in your yard.

Using one of the methods above won’t give you total protection or be long-lasting. It’s best to employ more than one control method to protect yourself and your garden. Mosquito coils could be one of the means you use to repel mosquitoes.

Photo of author


Peter spends most of his time outside in his large garden. He has been fighting mosquitoes for a few years trying different traps and repellents without using agressive chemicals.