Thermosolar Insight

I have been part of the Solar Bee Project at Berwick since its launch back in 2019, and although one of its aims, namely to introduce a focus for biodiversity and increase public engagement with solar farms, the Thermosolar Hive and Varroa control part of the project has been a little more of a struggle.

As with any hive system, they have their methodologies and I had found it difficult to establish the processes and principles as the bee colony and the hive become one unit, and although I have a certain understanding of the former, the latter was proving a bit of an unknown quantity. The manual we have is very comprehensive, but as with many things, comprehensive instructions don’t always make for clear understanding, especially when there is the highly variable aspect of a natural organism at the centre, and I felt I needed a steer on what was essential, and what was desirable, or just preferable.

Nick, of Naturesave Insurance, kindly arranged a Zoom meeting with Jan Rája in the Czech Republic who is one of the inventors of the Thermosolar hive, and another beekeeper in the Solar Bee Project (from Plymouth here in the UK) so that we could discuss some of the mechanics of the hive and the thermotherapy treatment. Below are a few clarifications:

  • I need to put spacers on the front insulating panel so that the warmth can circulate; it should not be flush against the metal plate (which is the ambient heating window)
  • Thermotherapy treatment needs to occur in the mornings (ideally starting at about 8am) as the sun is rising, in order to catch the rays on both the front window and the top Thermotherapy panel so as to take the shortest possible time to reach the maximum heat for mite treatment
  • Thermotherapy penetrates approximately 40cm down in to the brood nest, so the majority of the brood needs to fall within this area in order to be treated. Any bees wanting to vacate can do so – the queen and the nurse bees move towards the cooler part of the hive during the time the hive is being treated
  • Frames need horizontal wiring (or, in my case, kebab sticks) to provide structural integrity while the heat treatment is occurring
  • Fresh white comb is not robust enough so the colony needs to have matured, with firmer wax before treatment can be carried out
  • Many beekeepers find that the Thermotherapy is not required as the ambient heating is sufficient to disrupt the reproductive functionality of the Varroa

To me, the ambient heating is really interesting. We all know that standard National hives are thin-walled and give the bees a LOT of work to do simply to maintain their core temperature, and this borderline-cool also favours the mites. Well-insulated hives cannot take advantage of solar heating as of course the sun hitting the side of a thick-walled hive will not penetrate, so the window in the front of the hive allows for the sun to warm the bees, without then losing the heat.

On to another difficulty: propolis, and the result – condensation. The roof of the Thermosolar hive has a mesh with a ventilated material in the casing which allows the moisture created by the respiring bees to be expelled. The bees, however, see this mesh as a problem and consequently coat it with propolis, their go-to solution for anything rough or out of the ordinary in their hive, thus drastically reducing the efficacy of the ventilating properties, and causing condensation. It also means it is very difficult to get the roof off as the frames are stuck to the underside of the roof.

The solution is to put a cover across the top of the frames during the spring, summer, and particularly autumn when the bees winterise their home, so that the bees don’t feel the need to propolise, and they can also ventilate their hive at the entrances using the usual method of fanning to create a current. In winter, when the bees are tucked up and not carrying out home improvements, the cover can be removed, and there is a functioning roof to wick away the inevitable moisture. The best cover is a sheet of thin, firm plastic – similar to those used on poly nucs. There is not space to put a crownboard so it needs to sit directly on top of the frames. I am hoping this will also prevent the frames coming up when I take the roof off. (Thanks to Lee Lewis for asking about the cover in the comments.)

It was brilliant to talk in real time and hear both Jan’s instructions and philosophy, and it went a long way to helping me feel more ‘bonded’ with the hives. I will see how the colonies are once the weather improves, as I am conscious that they have had to cope in a suboptimal hive arrangement: sorry bees!! Jan is posting us some spacers for the front frame so that will be a start. We will also get the new instruction manual, and hopefully access to a couple of books that are in the process of being translated from Czech to English.

Thanks again to Nick and Jan.

20 Replies to “Thermosolar Insight”

  1. Great article, thanks, as I will be trying the Thermosolar Hive this year for the first time. Could you please tell me what Jan suggested we use a cover to resolve the propolis issue? Cheers!

    1. Hi Lee – thank you, I have just updated the post as I realised I didn’t say anything about the actual cover. Jan suggested a thin plastic, so I presume you are familiar with the plastic sheets often used in poly nucs and hives? It can’t be as thick as a quilt or crownboard, and I used a sheet of hessian one year which the bees soaked in propolis so I wouldn’t suggest that either! Hope that helps. Do let me know how you get on with your TS hive 🙂

      1. Thanks, Jennifer, that’s great information. Yes, I know the type of plastic you mentioned. I’ll give it a try this year if I see condensation becoming an issue. I live in an extremely dry region, so I may not have the same challenge that you have experienced. I’ll follow up later in the season with some results. Take care and thanks again for the excellent website and postings!

  2. I’m in Wenatchee, Washington State, USA. It’s a major fruit tree agricultural area that’s essentially a desert. The only reason anything grows is due to irrigation from the Columbia River. So, not a lot of ambient moisture to deal with. Yes, let’s definitely stay in touch. I’ll let you know when my hive arrives…

    1. Ah ok great – yes that is a very different climate to the grey and soggy south east of England 😉 it would be great to exchange info!

      1. Happy to! I think you have access to my email through your blog post verification, correct? If so, feel free to email me with your info and I’ll respond with mine. That way I don’t have to post my contact info on an open forum. Thanks!

      1. I thought something like that would be harmful because the heat given by the bees emitted the exact temperature they needed.

      2. The bees can tolerate an increase for the short time during the treatment, plus the majority will vacate the hive as the temperature increases just as they would on a hot day. It might be a bit weird for them but it’s preferable to being sprayed or fumigated with a mite treatment…

      3. That makes sense… I’ve never thought about what they do on hot days.

        You sound professional 😁

      4. I’ve learned stuff 👍

        I appreciate your blog and dedication to bees!

  3. Hello I will be buying a thermosolar hive this year, can you give me a contact on you to consult a few things? That would be really helpful.

    Thank you

      1. Hi Jen, thank you so much for your reply. Actually, I am from the Czech Republic which is where the thermosolar hive is from but there is just no enough information out there from the actual users and this article has been by far the most informative and objective that I could find. Also most of the information that I did manage to find was from before 2017 and was overwhelmingly negative so I am wonderig whether the design and the reliability of the hive has improved since then.

      2. Hmm, I am not sure it has improved, to be honest. I have not had any positive reports and I think a lot of people have bought them and ended up using them as regular hives which is ok, but as I discuss, I don’t feel the construction is particularly bee- or beekeeper-friendly in spite of its insulation credentials. I still think the assumption that bees will behave in a designated way and in accordance with the instructions (!) is ambitious and makes the hive difficult to work. Sorry I can’t be more optimistic!

      3. I see, ok thank you so much anyways.It is really a shame, I was looking forward getting into beekeeping without having to use all the chemicals be it even the organic ones.If you would remember about anyone who is still using the hive in the way it was designed for please feel free to give them contact on me: … or if you know about a different hive, working on a similar principle that actually works please let me know. But as I said, thank you so much and again I would just like to say that this is a really a great article about the thermosolar hive.

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