Once upon a time, even the most well-built homes were drafty to a degree. There were lots of tiny little nooks and crannies that allowed inside air to flow out, and outside air to flow in.
Then in the mid-1970’s energy prices began to soar. And the pressure of ever-increasing energy costs prompted lots of changes.
One of those many changes involved the standards that were applied to new home construction. Homes were built to be tighter and more energy-efficient. The tiny cracks and crevices in homes that permitted the outflow and inflow of air were no longer considered acceptable.
Today, new homes are more energy-efficient than they’ve ever been. But that increased energy-efficiency might come with an unanticipated cost.
Indoor Air Pollution is a Rising Concern
The typical home is host to a number of airborne contaminants that can have a negative impact upon the health of the occupants. Some of the more prevalent indoor pollutants include:
Radon: A radioactive gas that’s present in many homes to varying degrees, and is suspected of causing thousands of cases of lung cancer yearly.
Ozone: A colorless gas that can cause shortness of breath, headaches, coughing, fatigue, and other symptoms.
Formaldehyde: Commonly used in the manufacture of furniture, building materials and many household products. Formaldehyde is classified by the EPA as a probable human carcinogen.
Carbon Monoxide: A gas that is odorless, colorless, and that interferes with the ability of blood to deliver oxygen throughout the body.
Bioaerosols: Airborne biological contaminants that can include bacteria, viruses, mold and mildew fungi, dust mite allergens and animal dander.
According to the American Lung Association, indoor air pollution has increasingly contributed to the occurrence of respiratory diseases such as lung cancer and asthma. The Environmental Protection Agency rates indoor air pollution as the fourth-largest environmental threat to our health. And the World Health Organization estimates that nearly 2 million people die prematurely each year from illnesses directly attributable to indoor air pollution.
Is Your Home Sufficiently Ventilated?
The greater energy-efficiency that results from modern homebuilding standards is not a bad thing, certainly. But tighter homes means that more thought must be given to ventilation standards. And while proper ventilation is important for all homes, it’s particularly critical for homes built to more modern energy-efficiency standards.
How much ventilation does your home require to keep indoor air pollutants at safe levels? Unfortunately, there’s no simple answer to that question.
The American Society of Heating, Refrigeration and Air-Conditioning Engineering (ASHRAE) provides formula-driven guidelines for calculating the ventilation needs of a given home or structure. The formula (ASHRAE 62.2) juggles variables such as number of bedrooms, square footage of floor space, household appliances, and others. Using the formula along with ASHRAE guidelines will provide the most accurate guidance for structuring your home’s ventilation capabilities.
But in general, a home should be able to exchange inside air for outside air at rates ranging from 30 to 140 cubic feet per minute, depending upon the specific variables of the home.
“Build Tight and Ventilate Right”
That’s the new standard in homebuilding. Build homes tight so that energy loss can be reduced as much as possible. And then provide for sufficient mechanical ventilation to assure that indoor air pollution doesn’t become a problem.
So if your home was “built tight,” that’s a big help when it comes time to pay your energy bill each month. Just make sure that your home is also being “ventilated right.” It’s important.