The video from This Old House is helpful. But the filter at the furnace is not the best you can see right through it. He should have replaced it with a more efficient pleated type. The better the filter the less dirt will build up on the evaporator.
Our furnace has the 5" pleated MERV 11 filter. The evaporator is squeaky clean and the fan is on year round.
OTA, CM4221HD, 3410 amp, 4 way split, HW-150 PVR.
FTA, Openbox S9, 33” dish, PLL LNBF. Stab 90HH.
Last edited by Jorgek; 2019-06-20 at 09:01 AM.