Anyone who has spent any time in the Scottish Highlands will have experience of our national air-defence system – midges! There are many methods of keeping them away, from lighting a fire to wearing a net, and the arguments about the merits of the various chemical repellents have sustained conversation over many a bothy dram.
I recently stumbled across another method which piqued my interest. The Thermacell MR300 is a lightweight, gas powered unit which claims to create a “20m² zone of protection”, and would have been handy on my camping trip to Loch Ossian, where I became midge food for the evening while cooking dinner. For less than £30 I was more than willing to give it a go.
There are a number of different designs of Thermacell available. There is a very small and light Backpacker unit which screws on to a stove canister, and there is a larger Alexa sized Halo unit which uses the same gas and refills as the MR300.
The MR300 comes with a canister of butane gas and a pack of three repellent treated mats, giving a claimed total of 12 hours of protection. The canister is supposed to last for 12 hours and each pad for 4 hours. You can only use Thermacell refills with this unit, and a 12 hour refill pack retails for around £10. The unit doesn’t come with a storage bag, so you might want to find something suitable to protect it while packed away.
To prepare the unit for use, remove the black base from the unit. Remove the cap from the butane gas bottle and screw it into place. Take a blue repellent mat from the sealed pack and slide into the space between the plastic grille and the silver heat exchanger.
To operate the unit, switch the slide to ON and then press the START button. You should try to do this in a shielded area. You should then sit the unit flat down, grille uppermost, and check that it is actually operating. There is no great flame or light, so you will need to look carefully for signs of repellent vapourising. Then simply leave it to do its thing. It takes a bit of time for sufficient repellent vapour to build up, so if you are being plagued by midges it’s probably best to leave the area for a few minutes while it builds up. Each mat lasts for around 4 hours and as the repellent vapourises the mat will progressively turn from blue to white, and when all the blue has gone you should change the mat for a new one.
I chose the MR300 unit as it is a stand alone unit. I’ve found that the time you might be most plagued by midges is when you are static and in all likelihood you will be cooking. If you use the stove canister mounted Backpacker then you will probably have to switch it off to cook – or carry two canisters. Not ideal. It’s far easier to set this up, let it build up its protection zone, and then make and eat your meal in peace.
I gave this unit its first run out on a recent loch side camping trip to Loch Tummel. Lochs are always a midge hot spot, and in the absence of a breeze they were out in force, and I was finding them to be a nuisance. I quickly set up the unit, and switched it on. It is difficult to tell if it is running (the Halo units now have an orange light which confirms that it is operating), but by looking for vapour, or feeling carefully for heat I was able to confirm that it was working. I went for a wander and allowed it to create the claimed 20m² zone of protection, before returning to get down to the business of cooking dinner. I was pleasantly surprised to find that it did seem to be working, and midge activity was significantly reduced in the immediate vicinity of the unit. There were still a few midges in evidence, but at a vastly reduced number, and as such I found them to be fairly insignificant.
The protection can be affected by breezes, and will be less effective in these conditions. It’s not recommended to be used inside a tent, whether this is due to the fact it has a heat source or due to fumes I don’t know, but placing it near an open tent flap will allow you to sit with the tent door open, rather than sealed away.
Weighing in at around 180g, it is a very lightweight unit, which makes it more appealing to stick in the rucksack on the off chance you might need it. I picked mine up for £20, but they retail from between £20 and £30, so shop around – after all the £10 you save could buy you a pack of refills. Even better, if you get a shop that price matches you could potentially get it for under £20. A bargain!
While testing this I did not use any other means of midge deterrence or protection, so that the test would not be affected by other factors. First impressions are good, it appears to do what it claims to do, and I’ll certainly be carrying this in future.
The Airdrie Rambler 
Superb review and just what I need as I get eaten alive everywhere I go. Do you think it repels other nasties like horseflies/clegs? I suppose they’re not really active in the evenings though when you’re camping or sitting out.