Question: I have pleated air filters for my furnace that have a wire meshing on one side. Which way does the filter go in the furnace with regards to airflow direction. With the wire side opposite of airflow or on the same side as the direction of airflow?

Also, for replacement, what Merv value should I use, is it best to find the highest value or is some lower value actually better?

Many pleated air filters have wire mesh on one side of the filter. This wire mesh is used to improve the filters ability to stand up to the forces exerted on it as air passes through it. The longer the filter is in use the dirtier it becomes and more force is exerted on it. If there were no wire mesh the filter may collapse and be sucked out of the filter rack.

Wire mesh is usually found on filters that are made of cotton or some other filter material that is not sturdy enough to withstand the stresses they can encounter in a heating or air conditioning system.

The filter should be installed so that the wire mesh side is toward the fan allowing it to hold the filter material securely in place so that it does not collapse. For more information on this topic read which way do furnace filters go.

Pleated air filters with wire mesh on one side of the filter usually have lower Merv ratings than pleated filters that are sturdy enough to hold their shape without the extra support.

One of the benefits of these filters is that they have less impact on air flow than more efficient pleated filters but you also don’t get the filtering capabilities that the more efficient filters such as Nordic Pure will provide. It’s really a matter of preference. If you want cleaner air use filters with higher Merv ratings. If clean air is not a concern for you then you can use one of the less efficient pleated air filters.

Question: I currently have an electronic air filter, (electro-air) by White-Rodgers, and the power pack goes dead every 15 months or so.  It is getting costly to replace each time.  I am thinking about going to a cartridge type filter instead.  Can I do this, since the ductwork was set up for the electronic filter and is 6 1/4″ wide between the furnace and the air flow duct.

You can probably install a 5″ thick pleated filter into the unit.  Remove the electronic element and slide in the pleated filter. Measure the inside dimensions of the unit to ensure you get the right size filter.  You can order 5″ pleated filters here.

This would probably be the easiest fix.  You could also modify the unit and install a 2″ pleated filter.  You just need to make sure the filter is held in place properly.

You can get special order sizes here.

Question: With regard to pleated air conditioner filters do you think I can go with a MERV 6 filter or do you think I will be better served going with a MERV 8 filter?

A MERV 8 filter will perform better than a MERV 6 filter but the difference will be minimal. If you are not too concerned about dust a MERV 6 filter will do a good enough job. If you are looking for a big improvement in dust control you may want to try a MERV 11 or 12 pleated filter.

Pleated filters in the MERV 5 to 8 range will stop particles of 3 to 10 microns such as some mold spores, fibers, dust mites, some bacteria and fiberglass among other things.

MERV 9 to 12 filters stop particles of 1 to 3 microns such as smoke, bacteria, spray, fumes, coal dust and auto emissions and many other things.