I am curious what other HVAC professionals think about UV lights? I have had customers tell me how less sick they are, and how happy they are with there UV light. Some have told me that there alergies have almost gone away since there UV light was installed. I am debating if I should put one in my house. I also wonder if they are effective at killing mold and yeast spores. I my self think the return is the best place to install a UV light, yet there is arguments for both supply or return installation. Let me know what you think.