The Brand „Thermacell®

Thermacell® Mosquito Repellent was patented by The Schawbel Corporation (now Thermacell Repellents, Inc) in 1999.


Rigorous testing in extreme conditions by the U.S. Department of Defense proved Thermacell products work as advertised.

Thermacell products are effective in warding off biting insects. The repellent creates a 4.6 x 4.6m zone of protection against mosquitoes, black flies and other flying insects. This award-winning product has been recognized by leading entomologists and outdoor writers as the solution to making outdoor activities enjoyable. Today, Thermacell is sold in more than 30 countries in North America, Europe, Africa, and Australia.

The company’s research, development, and engineering facilities are located in the U.S. and Asia.

The functional principle


The functional principle of Thermacell devices is vapourising an active ingredient into the air by heating up a mat without open flame.

The energy source is a patented butane gas cartridge which is screwed in into the device (handheld or lantern). This butane gas cartridge delivery energy for around 12 hours. By switching on and igniting the device the metal plate under the mat is heated up to a defined temperature and vapourises the ingredient in the mat. One mat delivers protection for around 4 hours (L4 long life mat´s up to 12 hours). Due to the fact that there is no open flame the usage of the device is abolutely risk free and the usage of butane gas cartridges makes the device totally portable to be taken along everywhere.

The used ingredient varies from country to country. Depending on specific country we use d-cis-Allethrin, Esbiothrin or Prallethrin. The active principle of the various biocides is basically similar. The released portion of ingredient is designed to protect against flying insects in the size of mosquitoes. Larger flying insects recognises the ingredient as well. In order to protect against bigger flying insects, you need a highjer concentration of active ingredient which can not be realised outdoor during proper usage. For humans, pets, farm animals and plants the biocide is – if used properly as mentioned in the instruction manual – hazard free.


Frequently asked questions

Here you find a summary of the major questions and answers about the products from Thermacell:

Can I use the product indoor?

The product is designed for outdoor use. If you want to use the product indoor you need to make sure to create sufficient fresh air circulation. We have customers using the product to repel insects off their boat, camper or raised stand after the winter or using the product as invisible insect barrier in the transfer zones in between indoor and outdoor.

How does allergic person react against the active ingredient?

We had no single negative reaction so far. Since the year 2000 the devices in different designs comes with the same working principle and are applied millionfold to different markets without any negative reaction.

How do I know that I need to exchange the mat?

When the active ingredient is fully vapourised the mat changes colour from blue to white. As soon as the platelet changes to light-grey or white you need to replace it by a new mat.

Short instruction

Open device (handhelds: pull off cover on the bottom; lanterns: push both flaps on the bottom and pull the upper part from the lower parrt in linear movement) and screw in a full butane gas cartridge. Switch on and wait for 10 seconds, then push the ignitor several times. In the checking tap you will now recognise a blue/orange glow.  Unwrap a platelet and place it under the black grille. Wash your hands thoroughly. The device needs around 15 minutes to build up the protection zone of around 21m².

My device does not ignite. What do I need to do?

We have a failure ratio of less than 0,3%. In this case unscrew the butane gas cartridge, check fill level and screw it in again if sufficient fill level. Switch on and wait for ~one minute and push ignitor several times. If the cartridge is almost empty exchange it with a new one. Make sure you screw the cartridge tight like a light bulb.

What happens in windy conditions?

Above air movement of more than 15-20km/h mosqitoes stay on the ground as they can not fly against this wind force. Below this wind speed or at slight air movements make sure the vapourised ingredient is carried with the wind into your direction. At changing air movement it is recommendet to use two or more devices to build up a reliable protection dome placing the devices on the edge of the protection zone. Best protection is granted under sunsails, umbrellas, awnings,… where the vapourised ingredient can not be blown away.

Can I use the device during my favourite sport?

The protection zone need some time to be built up. If you want to do sport with rapid movement (mouintain biking, byciclying, jogging,…) we do not recommend these devices. For such sport it is better to use personal insect repellents like e.g. BushMan.

What to do if I used a platelet for just one or two hours and it doesn´t change colour to light grey or white. Can I reuse them?

Yes, you can reuse platelets which are not fully vapourised. For longer timeframes in between the usage store the device and the platelets in a dry and cool place where children and animals has no access. In order to avoid the normal vaporisation into the atmosphere and to hinder the mat drying out of the active ingredient we recommend to fold the platelets into a plastic bag.

Why are Thermacell® Devices better than Lotions, put onto the skin or other products?

Many Lotions contain ingredients which should not be brought into mucous membranes like eyes, nose, etc where these products can cause irritations. Especially babies or infants are not used to such products. Some lotions can cause stain on clothing. Thermacell offers a comfortable and contact free protection zone.

Has the LED-light some influence on the repellent function?

No, the LED-lighting is a additional and comfortable feature. One load of batteries lasts for around one season (depending on the light setting choosen)

The Thermacell device produces heat. Can I use it in the woods?

There is no open flame which makes the product safe in application. It can be carried everywhere.

How does the active ingredient trans d-Allethrin work?

The active ingredient has only effect on cold blooded species like insects and has a neurotoxic effect. The concentration is designed to have best effect against mosquitoes and flying insects in comparable size. The ingredient has the same effect like a narcotic agent. As aquatic animate beings are cold blooded too make sure that the platelets or mats does not get in contact with water, lakes, sea,… to protect aquatic life.

Can I carry the device onto an airplane?

Device and platelets are no problem if you check in your luggage. The butane gas cartridges are not allowed to be carried on an airplane.

What about the comparison with ultrasonic repellers and essential oils?

Mosquitoes does not hear; they take up the sonic waves with their tentacles. Thats why ultrasonic repellers have almost zero effect. The ~100 species combine different hunting parameters and also the size and the frequency of the wing beat is different which makes it almost impossible to repel mosquitoes using ultrasonic.

Essentials are also almost effectless as the concentration of the odour and ingredients is not high enough to repel mosquitoes efficiently.

The price is relatively high?

The main device is a single investment for many years as it is reusable. Based on the refills you pay 0,50 EUR per hour protection. Compared with other products this price is – based on the fact that it reples mosquitoes efficient – relatively low. If you calculate the investment into all items for a BBQ-party with ~70 Euro, the cost for one hour of efficient protection is very low. The Thermacell device can be switched on and off to your comfort while lotions or other protection sprays used outdoor are lost as soon as they are applied. In addition to this such repellents are used in a higher dosage which makes them more expensive and these products does not offer the same comfort like Thermacell.