There have been posts here about someone doing very similar. How much trouble would it be to put a meter on to see the consumption. I think someone in Finland was using as little as a 10 watt christmas tree light bulb. Those meters are less than 20$ and will give instant current draw and total kw consumption.

I would make a small bet that the savings in honey consumption would more than buy the power.

edit; you will likely get some slag from the folks who say you will spoil the bees! Have to give them "tough love" to grow up strong!

 

I'm considering a similar set up where I have power, and a shed.
what type seed heating mat did you use and how close does the thermostat keep it to set temperature?

GG

 

What hive setup are you running?

 

From my experience I concluded I don't want heating.
Been there - done that.

Instead of proper clustering, I observed the bees only trying get closer to the heater and running all over the hive, eating too much honey and eventually just pooping out.
It goes totally counter to the normal and natural conditions.

Actually, very slight heating maybe beneficial in very temperate places where the bees hardly need to cluster anyway - like in UK.
It maybe.

In truly cold places (WI, MN) with prolonged cold dearth of 5-6 months - heating only screws up the normal clustering behavior.

My take.

The true priority is (1)bee health and then (2)appropriate insulation.
Toying with the heating only takes you in a wrong direction IF you have poor survivability issues.
You should be looking at the actual root causes (#1 being the mites), not be trying to bandage the issues over with a duct tape - what the heating is.

IF your survivability is good anyway - than heating is even more waste of time.

Unless you enjoy toying with electricity - than sure, go for it and play.

 

While you are right in general, as you go further north more elaborate measures are needed.

I would also hesitate to criticise the methods of any beekeeper with 10 hives who has had even 1 year of 100% survival.

 

Notice the heating pad temp is set to be on 32F and colder. The bees will not be crawling all over that! Temperature at bottom of cluster will be unchanged at the normal~40F . The way I understand it is that it will temper the incoming air that well might be as low as -30 F. It will simply lower the amount of bee energy needed to keep it there.
Something like that might make the difference in survivability of small colonies.

A fellow up in Northern British Columbia is overwintering quite a large number of minies in a queen castle setup I believe. A bit of tempering the outside air just might up the survival odds enough to make it worthwhile.

 

Owens studied this back in 1950.

A rough summary of his experience (in Madison WI) was that inside-the-hive heaters didn't work very well because the bees had a tendency to cluster near the thermostat sensor.

However, a heating tape on the outside of the hive, with a moisture barrier over the hive and insulation (maybe R6) outside of that was beneficial. His insulation was fiber, and it tended to get very wet without the moisture barrier. So all of his insulated hives had a vapor barrier which also resulted in dramatically less air exchange most likely.
Power consumption was quite low, about 15 watts at 40F setting if I remember correctly.

Food consumption was less with the heat tape, and colonies lost less weight.

None of his hives died. Not the insulated ones, not the bare wood ones, and not the insulated-and-heated ones. It was 1950. Bees didn't die over winter.

This is from memory - I was planning to give a book report on his research but haven't gotten to it. Owens doesn't present his data in a format that is useful for the current topic.

In a hive with limited ventilation most heat loss is by conduction through the hive walls and top. At least that is what my calculations show.

Any way of providing heat inside of the insulation envelope that doesn't disturb the normal activity of the bees is probably helpful. A heating mat below the hive would do that.

The bees know what the temperature is outside, even in a warm hive. I don't think that healthy bees would be prompted to brood excessively by a warmer hive when the outside temperature is cold. However, a thermostatically controlled heater could save a colony that started brooding before a late cold snap.

Heating an uninsulated hive would be rather more expensive.

 

I think that the location of auxiliary heat would have considerable impact on its relative benefit. I see value in having the walls cooler as they probably are a major driver of the convection effect if the heat were to be applied to the walls. Convection is not our friend here.

Heat source at the top will also take away the bees discretionary control. I think it would be preferable to use the heat to temper the incoming air and allow the bees to top it up to their preferred range. This arrangement would also place the thermostat down below the cluster much nearer the heat source at the entrance; also unlikely to be propolised by the bees or be influenced by their body temperature.

This is based on the assumption that a basic condensing hive is being discussed.

I think it possible that the conclusions reached 75 years ago that the hive heating was not much benefit, was flawed by by an oversight in their test process-------
Location of applied heat and its sensor, plus using the then favored upper ventilation concept.

Change those two factors, and I think a different conclusion may be reached.

 

I use top insulation (R-20) and side/bottom insulation (R-10) during the winter.
My insulation is rigid foam made into a box that can be removed, but the foam under the screened bottom board stays put. Expecting a La Nina winter this year I added an insurance measure. Sliding out the inspection tray, I replaced it with a seed starting heating mat on a thermostat set to 32 degrees F. which was close to the average winter temperature during the warm winter we had in 2023-24. I had 100 percent survival that winter, so I thought it might help the colony out in fluctuating or brutally cold conditions. (we've had -18 and colder here in MN).
To elaborate: the thermostat only calls for heat when the tray area is below freezing.
At last inspection Jan. 16 when it was 38 F, I saw activity in all 10 hives plus the observation hive. I use plexy inner covers in winter for inspections. The fondant consumption was normal, similar to other years and the undertakers are hauling out a normal number of corpses.
This is an experiment to see if I can keep survival at 100 pct. regardless the type of winter. This requires very little electricity, far cheaper than colony replacement, so why not test this out ?
Has anyone else tried something similar and how did that go ?
What insulation values, sheltering (or heating systems) work for you ?

Keep us posted.
I think R10/R20 is about right. A lot depends on the size of the colony. Bigger colonies have an easier time in cold weather.
I have been making some measurements on my hives and have worked out a way of estimating the amount of insulation you might want. It isn't well validated and involves some hand waving, but you might find it interesting. It is in the thread "Winter Follies 2024".

 

...
Has anyone else tried something similar and how did that go ?
What insulation values, sheltering (or heating systems) work for you ?

Jerzy Siudalski, retired electrical engineer, does it for over 30 years, I think:

 

My thought is, heating is bad.The bees will take cleansing flights when it is too cold to fly. They will eat more honey and start brooding up too early. This is what works for me, in northern Illinois. I treat for mites, feed like crazy in the fall. I leave each hive 60ish pounds of honey. Reduce hives to 2 boxes. I use a bee cozy and a quilt box. No upper entrance and the lower one at its smallest. I feed them 4 sugar blocks, 2 lbs each. The thought is, the quilt box gives the hive more insulation at the top. The cozy gives less insulation on the sides. The water that doesn't get absorbed by the quit box will condense on the sides. Gives the bees water to drink. This has worked well for years.

 

Glad you have found something that works in your location.
If the people who have tested various methods of heating can be believed, heating applied to the outside of the hive under insulation has a modest benefit in food consumed and results in larger colonies in spring.

This should be qualified as follows:

In large colonies (8 to 9 pounds of bees)
With Italian bees
Prior to the introduction of Varroa
In northern continental climate (Madison WI)
When the hive wall is held at 40F or less.

Any other set of conditions would need to be tested.

However, at that time (1950's) survival was not an issue. Bees in plain boxes with standard telescoping outer and notched inner covers also survived without difficulty. They consumed more food and lost more weight -probably due to a slightly later start of brood rearing.

However, at the modest temperatures that were tested, the effect of heating on timing of brood was very slight, less if I recall correctly than the effect of insulation.

 

One thing I have learned is that pretty much everything that makes sense to me about how bees and hives should work has turned out to be wrong.

However, when I look at the results of experiments I and other people have done, after I think about it, the results make sense.

I wish that Beesource had a sort of autocorrect AI that would go back and weasel word my earlier strongly expressed opinions so that they don't directly contradict my later strongly expressed opinions.

This is nowhere more glaringly obvious than in on the topic of wintering.

Things I was wrong about:

Ventilation

I began with the idea that plenty of ventilation is needed. Top and bottom.

Now I have bees in a hive covered in plastic with no air entering or leaving except through a hole in the bottom board. The bees appear not to care much. Though they liked the vented hive just as well, from what I can tell.

Insulation

I began with none.

Now I have R20 top and between R10 and R8 on sides.

Either way, the bees did OK.

I thought that most of heat loss from a hive was due to air exchange. But after doing some calculations I conclude that most heat loss is through the hive walls. This is more true for uninsulated or lightly insulated hives. But it is true for well insulated hives too.

And there are other things as well.

Maybe I should be a bit more careful with my opinions. But what is the fun in that?

Experiments that test a vs b, and even those that try something different from "normal" are a good way of finding out what I don't know.

 

I find myself often entertaining contradictory explanations for what I see. Depending on which way I tilt my head I tally up results and try to test them against the other head tilt.
I think that is what is called cognitive dissonance!

It seems that some people come to conclusions and stick to them; that appears to be a more comfortable situation.

 

Really interesting setup, and I love that you're testing new ideas to improve winter survival—especially in brutal MN temps! Using a heating mat with a thermostat in the tray area is clever. Keeping it just above freezing without overheating the brood sounds like a smart, low-risk approach.
I haven’t personally tried heating, but I do heavy insulation (foam board on top and sides) and a quilt box to manage moisture. My survival rates have been decent but not perfect, so your 100% has me thinking...
For folks in the UK looking to build or maintain similar systems, services like Property Maintenance 247 | Local UK Tradesmen Services can help set up low-energy electrical solutions or even assist with outbuilding insulation. Definitely worth the experiment.