Nice work there, I was considering a chest-type freezer to mod when I did my "
Freezerator". I decided against the chest-type because my house is very small and I knew that objects would want to live on the lid.
Your numbers look great.
I just did a hasty calc, and your setup is using around $10/year electric and my "Freezerator" is using around $16/year (at my local electric rates).
So, I am obviously shedding blood for the convenience of a door.
Another advantage is that your chest-type freezer should solve the problem of condensation, as I assume that you have a drain-hole located in the bottom of your freezer chest.
It may be too soon for you to know, but is the volume of your unit correctly sized for your needs?
I ask this because, for myself, I realized that I had always had too much refrigeration capacity, and food would get lost and spoil. So for my lifestyle, smaller is much better.
One more thing... if you follow my "Freezerator" thread, I developed my own Arduino temperature controller while I was waiting for the Chinese unit to arrive. The Chinese unit has a nice big display so that I can see the temperature, but the Arduino unit I developed is actually superior because it doesn't rely on an electro-mechanical relay (SSR instead), and it allowed much finer temperature control (fractional degree choices of ON-temp and OFF-temp).
Best,
-AC