If your home runs on central heating and cooling, be sure to replace your air filters about every three months since a dirty filter can make the system work harder, which wastes energy. Did you know the air filter needs to be installed in the right direction in order to work effectively? One side is more porous than the other, so if the filter is installed backwards, your furnace or air conditioner will have to use more energy to pull air through the incorrect side. The result is an increase in energy waste and filters that do not properly capture dust particles and other debris. To prevent this, install the filter correctly.