Does it matter which side of the furnace on which the cold air return enters. Mine enters the side with the blower motor in the squirrel cage. Does this make the furnace noisy? Is there a preferred side or bottom?

 

Usually the cold air return does in fact enter from the side at the bottom of the furnace plenum where the motor and belts are located, up through to the heat exchanger where the burner uses outside combustion air (usually from outside the house) and passes the heat to the returned air. Keep in mind the air filter does not filter the air you breath but only protects the furnace mechanism from large particulate debris like cat and dog hair. You do not need high priced filters for a furnace filter.

See the following diagram.



Will the location make a difference in noise? Depends on the make and model of the furnace. They all make noise. Will you hear it in the upper floors? Yes. Most catastrophic furnace failures are due to a cracked heat exchanger and or burner corrosion. Other part failures are repairable and usually worth repair.

 

“Keep in mind the air filter does not filter the air you breath but only protects the furnace mechanism from large particulate debris like cat and dog hair. You do not need high priced filters for a furnace filter.”


While I trust what you say is true, I thought removing particulates from the household air would be beneficial to people.

 

You can't expect a tiny little 1 inch thick filter located in the basement inside the motor section of the furnace to clean the air you breath. Think about it. Can't be done. If you need filtered breathable air you need to get a dedicated air cleaner. And that usually means a dedicated room also sealed from other rooms.

However, what I tell my customers, if if you have a dust problem or allergies then moving up to a better filter will help to a small degree. Otherwise I tell the customer to buy the cheapest filter and change check it every few weeks and plan on changing it at least every two months. Not the three months the manufacture recommends.

edit... Think of it this way. If you don't have whole house A/C, but keep you windows and door open for air in the summer, look at the screen at the end of the season and see how much dirt and dust they accumulate. You're breathing that dust day in day out. Again how can a 16 x 25 x 1 fiberglass filter handle that?

 

Everybody is correct, the quality of the filter, and especially the length of time the furnace runs, make that a very small amount of improvement.

 

I think return air is return air and it does not matter which way it comes from.Never noticed a difference in sound either but wasn't paying a lot of attention to that aspect.

 

Well is does matter where it comes from. You want to use the already heated air in the house from the living area to be returned to the heat exchanger to be reheated. You don't want cold air or air from outside or air from an unheated room.

 

I'm pretty sure we are talking where in the plenum box. Look it up.