Don't forget that heat rises! So for air to heat, it also thins out and floats on top. So don't forget that fans need to face down. They need to be placed at the top to circulate air down to the bottom. You can look at my profile. I built my own a while back with a 95% hatch rate. I now have others that I bought, because building more, I was not feeling up to. But, I still use it and it works great. I have 42 serama eggs in it now, within an egg turner and they are doing fine. A well-built incubator will give you years of service, and even grows in value with it's own success. Goodluck.