Question: Which pleated furnace filter is better from same company.
7 pleat or 11 pleat?

I would say the 11 pleat filter is probably better because more pleats per inch of filter allows for greater air flow. This is important for efficient filters. Quality manufacturers aim for as little impact on air flow as possible when designing their filters. As the efficiency of the filter material increases so does air flow restriction. One method of compensating for this is to have more pleats per inch of filter.

More pleats per inch of filter also distributes the dust collected by the air filter over a larger area and therefore can be in the system longer before needing to be changed.

Hepa air filters have many more pleats per inch than other filters that utilize the pleated design.

Question: I have recently moved into a house and the furnace uses an electrostatic air filter filter and I am unfamiliar with it.  We have 2 filters one is in the furnace and 1 is leaning up against the wall…the slot is big enough for both filters, do I put them both in or would that restrict the airflow…is the sole purpose of having 2 to alternate when cleaning the other.  Thank you in advance for helping me with this question….thank you also for the info on cleaning it this website is very helpful.

It is fairly common for people to have two electrostatic filters. While one is drying after being cleaned the other is used and they are alternated this way. You are also correct about using both of these filters in a heating or air conditioning system. Installing both filters at the same time would definitely cause problems with air flow.

Restricting air flow can cause many different problems:

Restricting air flow in an air conditioner

• Evaporator coils icing up
• Poor air circulation in the conditioned space
• Increased operating costs due to longer run times
• A decrease in equipment efficiency

Restricting air flow in a furnace

• Furnaces cycling on high limit switches
• Cracked heat exchangers
• Increased fuel consumption due to longer run times
• A decrease in efficiency

The above are only some of the potential problems that can result from restricting air flow.