Customer said that they believed the UV light was causing a smell within the home like burning or ozone and that it could be harmful to them. After inspection no evidence suggest that there is any electrical burning. Co levels are within stable ranges. I did notice the smell however could not find a source. I have shut off the uv system for the time being. I recommend upgrading the air filter to Aprilaire and a duct cleaning as they could absolutely benefit from both. Changed filter while I was here.