I have been in the skylight business for  20 years now and it still puzzles me how plastic dome style skylights ever became introduced into the market place. When my company installs a skylight in a commercialof residential property the minimum requirement is tempered glass over tempered glass. This make a lot of sense since falling objects (ice , hail, tree branches etc) could enter the home and cause property damage or in  a worst case senario injure the occupants. With tempered and lamintaed glass there is protection against this happening. With an acrylic dome style skylight there is very little protection against this type of damage.  We have seen numerous situattions where an acrylic dome style skylight was installed on a first story roof below an eave of a second or even third story.  We have replaced placstic dome skylights when huge pieces if ice have fallen from the eave, through the skylight and into the space below. Thank heavens no one was injured in any of these occurances but the possibility of injury or death still remains as long as plastic domes are still used in such situations.   

Plastic dome style skylights are also about 58% less thermally efficient than glass skylights. Unlike glass they fade quickly and there is usually seal failure withinin 5 years. Lets face it no one would install plastic windows in thier home regardless of the discount. So why then is it acceptable to install plastic skylights when they are exposed to all the rain, snow and UV rays more so than any window ever is? 

Please check your home and make sure that your family is not exposed to this unnecessary risk.