This is John from St Mary School. He's helping his parent change out a dirty furnace filter. You might not know it, but your central air conditioning system probably uses the same filter and blower fan that your furnace uses. Allowing this filter to get clogged up with dust and debris means your fan must work harder to move the same amount of air through your home's ducts. That means it could use more electricity. It could also be unhealthy. Check your filter according to manufacturer's instructions and change it when necessary. You'll keep your heating & cooling system cleaner and more energy efficient -- and you'll breathe easy knowing you're saving money!