This St Mary School family replaced their HVAC's air filter with a fresh one. That's smart! A clogged-up air filter means that your system's fan must work harder to move air through it -- and that means it might use more electricity! It could also be a little unhealthy, as dust, debris, pollen and other microscopic particles could get blown through your system's ducts and into the air you breathe. Change out that filter according its manufacturer's suggested schedule, and then breathe easy knowing that you're saving energy dollars!