Effective heat treatment of bees

Fight varroa mites with heat. I’ve decided to use heat treatment I take off it all and place a net early in the morning, before the bees fly, or I can do it the day before. If I do it the day before, I place a wedge so the bees can enter and exit. Those will I remove in the evening, when all the bees are inside. To be safe, I remove some of the boards and make a bit space between them. The bees need good space, when I heat up the house, since they will try to lower the temperature. With some rubber bands, I hold the two nets tight together and I need to remove the wedges in the evening. If the bees have to stay over the night, I close again. Also I open the buttom of the house to give ventilation to the bees during the night. Now to the heat treatment. We put the house on this heater, which is made of a buttom and a similar top. Then I mount the heater and last, the top. I make sure, that it’s comepletely closed. I now do in the same way as with the nets, use rubber bands to keep the heater tight to the house. This is the thermostat. The one that controls the thermostat is put in here. That means, that the hot air will be regulated before it meets the bees. That important, since the bees cannot take high temperatures. Now the ventilator starts and the heater, so now the thermostat goes up very fast. To control the temperature, I have some electronic thermometers. I tried to place a hygrometer inside, to calculate the humidity. I believe that the humidity will not change. Through this hole can I add humidity if it’s too high or low. Now I put in the thermometers in the top and the buttom. I also put in other themometers, because I want to follow how the heat rises. The temperature rises pretty fast. It takes about 15-20 minutes. This heater is my second one. My first was made by some recycled materials, but I made this one with better materials. Later I will show you how I made my first heater, so you can make it yourself, if you want to. My first attempt was made of wood. Not many believed that it worked, so I wouldn’t invest much in it. It’s a well isolated box with some rubber frames on the top sides. I will try to build it, so you can see how it works. It the same way as the other, the heater is just made of wood. The heater is made of a box with a ventilator and two 150W light bulbs. The reason I use the light bulbs is, when they are turned off, it stops making heat. It’s important, so the bees to not get overheated. The reason I use two light bulbs is, if the one goes out, the second is a backup. You don’t need to use two. It works fine with one – it just takes some more time I’ve made this pipe. It doesn’t matter what it’s made of, as long as it’s isolated. Now I place the top on it. Keep it together with rubber bands again. This heater can be made for under $160 It works completely like the other heater. The bulbs are connected in parallel. Make sure that the temperature never comes above about 44°c. Editor’s note: It works completely like the other heater. If you are interested in making this, I’ve made an article about it in this magazine. (The article can be downloaded in danish as an PDF with a complete building guide) The main building guide for this heater has also been translated to English and can also be downloaded here. You can also download an article about the results I’ve achieved with my heater. Now it’s been about one and a half hour, so let’s see how the bees are. You can clearly hear the bees cooling down the hive. These are the mites that the bees have dropped. Bzz Bzz Here you can see that a few bees could not take the heat. After the heating, about a thousand mites have dropped off the bees. I hope someone find this method useful and want to build their own heater. I am willing to help if I did not explain it thoroughly enough. I would love to hear from you if you find out any improvements or something that’s even smarter. This is not finished, it needs some more work, and it would be easier to do, if we did it together. The advantage of heating is that you can do it any time of the year, it has no influence on the honey, it’s completely poison-free and the bees do generally not take damage. Now it’s been about 30 minutes after the heating. The bees are busy drinking water. If you are interested in this heating method, you can contact me. More information in the description.


  1. I'll try the wooden variation – later, on summer varroa increase I'll send you my observations – takk så mycket Benny!

  2. Dear Benny,

    thanks for excellent presentation and that you share your knowledge . You must have extensive experience in heat treatment.
    I have not fined the pdf of your two publications in BIAL . Would you be so kind to sand it to me?
    How efficient is the treatment, how many times per year have you treated the bees? What is optimal the humidity ?

    Tx for you answers

    Best Matej

  3. HI Benny – Tak for din video. Jeg vil forsøge at bygge en 'Mite Killer' som din i løbet af vinteren. Jeg tror, du har en god ide her, og det ville fungere godt for den lille biavler. I 2017 har vi tabt mellem 30-80% af vores biprodukter hvert år afhængigt af det område, hvor vi bor, og vores bier er syge. Vi mister denne kamp …

    Jeg vil bygge noget som din "Mite Killer" i vinter og jeg vil fortælle dig det. Tak for din gode ide. Hilsner fra Minnesota USA – Chris
    HI Benny – Thank you for your video. I'm going to try to build a 'Mite Killer' like yours over this winter. I think you have a great idea here and it would work well for the small beekeeper. In 2017, we in the USA have lost between 30-80% of our hives every year, depending on the area where we live and our bees are sicker. We are loosing this fight…

    I will build something like your 'Mite Killer' this winter and I will let you know. Thank you for your great idea. Greetings from Minnesota USA – Chris

  4. Always impressed by Dutch ingenuity and generosity. Very articulate and well presented and a beautiful machine.

    I'm sure you have beautiful bee's aswell and they love you very much.

    Isn't it true that the Dutch are famous for their ovens? 🙂 lol.

  5. Hej, Jeg elsker hvad du har gjort. Det engelske link er brudt. Er det muligt at lave et nyt engelsk instruktionslink?

    Jeg laver den danske pdf og vil bruge Google translate og håber det giver mening.

    Tak fordi du deler denne vigtige information!

    Jessica USA

  6. Hej Benny, tak for din video og tager dig tid til at tilføje engelsk undertekster.
    Jeg vil også gerne undskylde for Steven Es kommentar, ikke alle engelsktalende er så uvidende som ham, eller forventer, at alle skal tale engelsk.

    Hi Benny, thank you for your video and taking the time to add English subtitles.

    I also would like to apologise for Steven E's comment, not all English speakers are as ignorant as him, or expect everyone to speak English.

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