In regards to the coated coils they are not treated with Teflon. The Technicoat coils use a phonelic coating which after a period of time will eventually cracks. The coating cracks because the coating has low elasticity properties and the expansion contraction of the material is less than the aluminum of the coil.
Bronz Glo coated coils use a material closer to rubber but still remains basically heat transparent. It has greater elasticity and will not crack. The Bronz Glo coated coils also have an anti-microbial mixed into the coating.
Contact Bronz-Glo in Florida and they can provide you with a contractor in your area that is an applicator. They also have spray cans of the coatings that can be applied with the coil in place by your local contractor. The spray cans are not as good as the immersed coil but it works fairly well.