I don't bake, but I once installed an off-the-shelf PID controller into my kitchen oven[1] and this gave me some insights on things that are normally kind of inconvenient to observe (what, with the bright always-on LED display glaring at me at all times while I was in the kitchen with a constant report of what temperature in there was).

Like: The oven light. It's an incandescent bulb, which is also to say that it's waaaay better at being a heater than it is at being a source of light.

I found that leaving the light switched on in the oven, and the oven door closed, kept the temperature right around 100F. It varied a bit depending on ambient, but never by more than a few degrees.

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[1]: It was an old Frigidaire-built electric range that someone gave me for free. It worked, until one day when I switched it on at a sensible temperature setting and put a frozen pizza in there. The temperature control then failed, and it failed stuck in the on position. The pizza was very badly burned and looked pretty crispy when I came back to it a short time later.

And when I tried to retrieve the pizza, the hotpad in my hand was converted directly from fabric into smoke as soon as it touched the pan.

While I lamented about the lost pizza and the expense of buying new replacement parts for an old freebie oven, a friend suggested using a PID controller and an SSR instead.

So I did exactly that: I bought the parts (including ceramic wire nuts and fiberglass-insulated wire), cut a square hole in the panel with a grinder and a deathwheel for the new controls, mounted an SSR in a recess on the back with an enormous heatsink, and it all went together splendidly. I put the new bits in series with the old bits, so it was never any less-safe than it had become on its own accord.

I miss that oven sometimes. It was actually kind of fun learning how to tune the PID, and to be able to reliably get a consistent temperature from it.

The oven-light discovery was just an accident; if I actually wanted 100F for some reason, I'd have just set the PID box to that temperature.