HOUSTON -- Air filters are some of the most commonly forgotten household items in your home.
If they're dirty, they can cause allergies to flare up and significantly increase energy usage.
But one quick walk through the air filter aisle at any home improvement store can be major overload. So how do you know which ones give you the most bang for your buck?
"It is overwhelming and most people are confused because they don't really know what they want or what they need," said Home Depot's Mark Scifer.
The price differences are also huge. You can get filters for under $1 or spend as much as $20 for one!
"As you go up in filtering, basically the weave gets tighter and the material is different to filter out more and more different items," Scifer said.
The best rule of thumb is to look at the MERV rating. It is an industry standard that rates overall effectiveness. The higher the number, the fewer dust particles and other airborne contaminants that can pass through the filter.
To see the handy MERV chart on which filters you need, click here
At Home Depot, they have their own color coded system.
"You have to look at the things that are problems for you. Some people have minor dust problems, some people have cats which is the most insidious of household problems," Scifer said.
We found a Nuisance filter that had a MERV rating between 1 and 4. It was originally made to protect your heating and air conditioning equipment, not to improve indoor air quality. You can buy them less than $1 each, but they remove less than 10 percent of the air pollutants and will need to be replaced more often.
"The pleated filter is going to catch most of what comes through, except the very small things," Scifer said.
MERV ratings 5 through 8 will remove most allergens, pollen, pet dander, and dust mites. It is equal to Home Depot's "good" rating and costs about $5 a piece.
Levels 10 to 12 will run you around $10 and removes 50 to 70 percent of pollen and mold spores, which is similar to Home Depot's "better" rated filters.
Hospital grade filtration is levels 13 to 16, and those will cost about $17. Spending $20 or more gets you levels 17 to 20, which add virus carriers to the list.
"There's no reason to spend $20 if you're filtering items you don't need to filter," Scifer said.
He says for most average homes, a "good" rated filter will work just fine. Scifer also said that the higher MERV number can actually leave your home with dirtier air than using a cheap $1 filter, if the Merv filter doesn't have enough pleats per foot.
How to choose the right air filter for your home