Is it possible to add direct venting to an existing appliance? I would like to get rid of the huge chimney running up through my house. And I would rather not have to buy a new boiler and water heater. Any other ideas would be geratly appreciated.
20x20? Is that the framed in size? Normally you would probably need about a 8" round type unless you have very large appliances. The only way to know for sure/meet codes etc is to call a licensed reputable chimney repair co. If you really hate it then consider some direct vent appliances.