The only energy costs involved are for the electric fans used to circulate the heated air within the kiln, and possibly to operate automatic vents.
(The only energy costs; involved; ) (The only energy costs involved; are; for the electric fans) (the electric fans; used; to circulate the heated air within the kiln, and possibly to operate automatic vents)
The only energy costs The only energy costs involved the electric fans
involved are used
for the electric fans
to circulate the heated air within the kiln, and possibly to operate automatic vents