A cooler box, a heater, a thermostat and a fan make a working incubator for a few dozen eggs. Here is how to build one safely, and when buying makes more sense.
By the IncubatorPro team · Updated 30 September 2026
What you need
An insulated box: a polystyrene (styrofoam) cooler box or an old bar fridge (with the cooling system removed). Wood boxes work but lose heat faster.
A heat source: a small ceramic heater or a 25–40 W incandescent bulb in a proper fitting. LED bulbs give almost no heat.
A digital thermostat with a probe, rated for the heater’s load. This is the most important part.
A small fan (such as a 12 V computer fan with its own adapter) to spread the heat.
A separate thermometer and hygrometer to check the thermostat.
A water tray for humidity, and a wire mesh floor to keep eggs off the water.
A small window (glass or clear plastic) and a few air holes.
How to build it
Cut a window in the lid and seal a piece of glass or clear plastic over it.
Make two or three pencil-sized air holes near the top and one near the bottom.
Fit the heater or bulb holder securely on one side, away from where the eggs will sit, and mount the fan so it blows across the heater.
Wire the heater through the thermostat. Mains wiring (230 V) can kill and can start fires: use proper connectors and an enclosed box, never exposed joints, and ask an electrician if you are not sure.
Place the thermostat probe at egg height in the middle of the box.
Put the water tray on the floor and the mesh egg rack above it.
Test before you set eggs
Run the empty incubator for at least 24–48 hours. It must hold 37.5 °C within about half a degree, day and night, and 45–55 % humidity. Check with a calibrated thermometer and hygrometer at several spots. If one side is warmer, move the fan. Then follow how to use an incubator, turning the eggs by hand 3–5 times a day (turning guide).
Homemade vs bought
A DIY incubator is a great learning project for a few eggs. Its weak points are uneven heat, hand turning, and no backup if a cheap thermostat fails. If you plan to sell chicks, those lost hatches add up quickly. An automatic incubator with a warranty removes the guesswork; see small incubators and the price list.
Rather buy a ready-made incubator?
Every model has automatic turning, digital temperature and humidity control and a 2-year warranty. Pay cash on delivery or by EFT.
