What should I do to make sure the filter on my rooftop unit is clean for maximum efficiency?

Periodically (every 2 months for full time users, every 6 months for seasonal campers), remove the return air filter located behind the return air grille and wash it with soap and warm water, let dry and then reinstall.

Never run the unit without the return air filter in place. This will plug the unit evaporator coil with dirt and may substantially weaken the performance of the unit over time.

Applicable to models: 457915.70X, 640312.80X, 457915.71X, 640312.83X, B57915.71X, 640312C35X, 459516.70X, 640312C85X, 459516.71X, 640315.80X, B59516.71X, 640315.83X, 540315.70X, 640315.84X, 540315.71X, 640315C35X, 540316.70X, 640315C85X, 540316.71X