Fan or fanless DIY incubator?

[CluckEmUp]

Are there any downsides to using a fan inside a small DIY incubator? Right now Im not using any fan, because frankly its a really small one (old computer case). I tested out the temps and it seemed stable from where the eggs were. But I did it too hastily and now realize only the middle eggs are stable (around the center) around 37.7C, but the two eggs closest to the 40w bulb are actually fairly hotter at 39C, whereas the furthest away eggs are coldest at 36C.

As far as I know these are still OK temperature ranges? So not sure if I need a fan. But, a fan will stabilize the temperature to be more or less the same everywhere.. so it sounds better. However, the bulb is fairly hot up close, so wouldnt the fan actually make the whole incubator hotter? (39C or higher) because of it? I could open up the case more but then I'm thinking it might negatively affect the humidity.

I dont have any kind of regulator for my light bulb, so the only way to lower the temperature is to make openings in the case (or remove some aluminium foil, as thats wrapped inside the whole case)

 

[Altairsky]

I have an old, fanless incubator that has the same problem: 35°C to the sides, 40°C in the center, while its thermometer is set to 37,7.
After losing 10 eggs out of 12, I would definitely suggest to try a PC fan and see how the temperatures goes. At least that's what I probably need to do.
I would also suggest a thermostat to control the temperature. I used the inkbird itc308 for fermentation purposes, but now I will probably need to use it to fix my incubator issues.

 

[CluckEmUp]

I have an old, fanless incubator that has the same problem: 35°C to the sides, 40°C in the center, while its thermometer is set to 37,7.
After losing 10 eggs out of 12, I would definitely suggest to try a PC fan and see how the temperatures goes. At least that's what I probably need to do.
I would also suggest a thermostat to control the temperature. I used the inkbird itc308 for fermentation purposes, but now I will probably need to use it to fix my incubator issues.

Sorry to hear you lost 10 eggs, those aren't good numbers! Hope mine will do better, but it's difficult. I actually just tried with an old USB fan I still had laying around but then the temperature kicked up too high everywhere (40C). So I had to remove some things to lower the temps, but THEN it had dropped too low to 35C.

So it needs quite some balancing, which I didn't quite have the time for just yet - so I removed the fan and reverted back. Middle eggs are stable 37.5C now, and just thinking moving the far eggs closer and the hottest ones a little bit away. Maybe not optimal but I can't work too much on the incubator now that the eggs are already in..

Will see how this batch goes and work the improvements on the next one.

 

[K0k0shka]

I had a bad experience with a fan-less incubator - big temperature difference around the heater and farther away - and it was helped greatly by adding a fan. It mixed the air up enough where the temperature evened out, but yeah controlling the actual temperature is a separate issue in itself. The fan just equalizes it across the whole space. I used a handheld mini fan from Amazon.