Before you buy your next house, there are a few good ideas to make the house smell better and eliminate the problems left behind by the former owners. Cleaning the air ducts and overall sanitizing is a smart thing to do while the house is empty and easily treated.
Biofilm, Crude, and Dust
After years of living, the stuff that clings to the inside of air ducts will scare most people. More than dust; we find dirt, pollen, bacteria, and chemical deposits that seem like a dirty set of lungs in the body of the house.
What you cannot see in a routine inspection is the tremendous need for air duct cleaning. Some home may not need air duct cleaning, but since the air system are called the “Lungs of the Home”, it makes sense to clean air ducts after years of living.
The buildup in the air ducts may be the most obvious deposit, but there is more to preparing a recent home purchase than a vacuum and a good cleaning. Smells tend to haunt a house for years after new owners move in. This is because of something called a “biofilm”. Biofilm is a very thin layer of organic matter that coats ever wall, shelf, cabinet, and is embedded in carpets and drapes.
More than a layer of neglected dust, the biofilm is a collection of grease, smoke, chemicals, and is the home of colonized bacteria that live happily beyond the reach of regular cleaning efforts.
Before you Buy a house?
Always check the air ducts (and dryer vents) for accumulated gunk. A mold inspection with air samples would be a good idea as well. Home inspectors are not mold inspectors, and they may ignore the ducts too.
Since you will likely live in this house for years to come, it pays to do your homework rather than find the problem later.
BTW, Change your furnace Air Filter
Many furnace filters need to be changed every three months (90 days). This will help prevent future buildup in ducts. Furnace filters are very important to the indoor air quality, problems with allergies, and further dust buildup in the air ducts.