<http://schema.org/description>
"Your furnace has the tough job of continuously keeping the air in your home warm. Your furnace, therefore, requires some tender loving care for continued efficiency. Not only should you change or clean your furnace filter regularly, you should also clean the interior of your furnace."^^<http://www.w3.org/2001/XMLSchema#string>
<http://home.howstuffworks.com/home-improvement/heating-and-cooling/furnace-cleaning-quiz15.htm>