Unspeakable layers of dust, dust mites, animal fur is affecting quality of the air in your house! Not surprising to have an allergy after all of that, right?  

Dryer vents are getting filled up with lint and debris with time. Also it is one of favorite spots of nesting for small rodents, like mice, birds or snakes. It can cause a number of issues, such as clogged dryer, or foul smell around the unit. If amount of lint is sufficient enough it can cause fire!

Clogged Chimney lines can cause unwanted fire, due to the amount of creosote on the walls. It is also on of the main reason of the creosote smell in the house.