A light bulb is one of the easiest and cheapest ways to provide heat inside your homemade incubator. A bulb is very reliable, low cost and safe to use.
I prefer to use a 12 volts power supply to power a simple low voltage halogen bulb. The most common ones range from 10 watts up to 50 watts.

I find a 10 watt bulb is suffice to get the temperature up and over 100 degrees F in my smaller incubator.

To keep things tidy its also a nice inexpensive idea to get hold of a cheap lamp holder. I used a small low voltage halogen option which worked fine and ensured a good connection.

So that should be all you need for a simple and effective heat source for your incubator.A light bulb is one of the easiest and cheapest ways to provide heat inside your homemade incubator. A bulb is very reliable, low cost and safe to use.