Well my first incubator is a is a large heavy cardboard box with a lift off lid that I put a glass window in. It uses 2, 25 watt bulbs for the heat source, controlled by a wafer thermostat. It also has a small CPU fan for circulation. The inside is lined with an extra thickness of cardboard that is also covered with aluminum foil to help retain the heat and humidity inside. It works great and maintains the temperature within 1 degree. Then I bought a new Hovabator 1602N on Ebay for around $40 US. It also works well and I am very pleased with it. I currently have eggs in the Hovabator that are due to hatch on the 20-21st. I also have the cardboard box running as a back up, to be ready in case something happens. If you don't feel your bator has enough air circulation , you could possibly drill a few small holes in it to increase the air flow.