Filters make a difference. I have an open-loop geothermal heat pump in my home. The filter where the water comes in needs to be cleaned periodically. If it gets dirty the efficiency is reduced. If dirty enough, the heat pump trips off. The air filter also needs changing a few times per year. I have a reusable air filter I clean and then put back into the unit. Filters on your vehicle, lawn mower or any other item in the house, need to be charged or cleaned on a regular basis. Forgetting this reduces the life of the item and increases energy consumption. And clean the grill behind your refrigerator! And under the darn thing, too! Stressing the compressor on your refrigerator can cause the compressor to fail. Have you seen what refrigerators cost? Yes, it is very frugal to clean and replace filters often.