Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
The basement system does not effect the first floor a whole lot since there's a door that leads to the basement from the first floor and it is usually closed. The doors to the bedrooms upstairs are always closed and it always feels comfortable up there. During our heating tune-up back in early October the tech checked the airflow on the air vents on our first floor and upstairs system. He said the airflow is proper for both systems. This tech is a very good one who works in one of the highest rated companies in my area.
Update... The new 12 inch return was installed (It replaced the 6 inch in the man cave of course) and the airflow in the basement has improved! The ductwork was also sealed up. Air leaks existed before. *Note* One of those 4 inch ducts on the right side of the plenum of the first floor system is for one of the bathrooms (this certain one is a half bathroom) and the other 4 inch is for the large kitchen pantry.
It's sad how the system has never been sealed up before. Before it was sealed, you can see how crappy the tape work was. There were not too many leaks though. Only a very few small ones. By the way we have a 14" x14" air filter in both returns now. Because of this, we no longer have a 14" x20" filter in the air handler.
Lordy, I swear you are going to give me grey hair when this is said and done. I thought that you had larger grilles! A 12" flex (depending on the lenght is equal to 500+ cfm. Those tiny 14"x14" filter grilles equal 392 cfm when the filters are new.
My preference is to always oversize filter grilles. Why? Because air filters get dirty! I.E., dirt = resistence to airflow!
A larger grille couldn't fit between the studs. The length between the studs are 14 inch. Our old filter took about a year to get A LITTLE BIT dirty. We always change the filters in our other systems once a month. We will now change the filters in our basement system once a month now.
There is inherent contradiction in those two statements. The filters are either trapping a lot of dust or they aren't. Once a month should be fine.
Dust isn't always black, or even dark. I no longer assume I can tell a filter is dirty by looking at it. I learned that knocking over a perfectly white media filter after the Infinity said it needed changing. (I have been too stupid to listen and have had to learn the hard way, ashamedly, too often. It's better to learn from the mistakes of others than repeat and pay for them yourself. This is for benefit of other non-pro's following this as GAlady seems up to speed on a lot of this already.)
I think the best way to truly know a filter needs to be replaced ESP. One of the nice things about good communicating furnaces, they know when flow is getting restricted and tell you.
Last week we also did call several good top rated companies in my area to look at the ductwork. They evaluated everything and said the ductwork for the first floor system was the right size and was in fine shape and the only thing that was needed was duct sealing. Obviously flex duct is everywhere down here and in most homes around here metal duct is not allowed. I guess it's just the south where work may not be the best.
Well even after the new 12 inch return was installed the game room still feels cooler with the heat on. The walls in our basement are very well insulated. I did a test the other day by taking the cover of the register off and with it off the temperature in the room warmed up. With it on not a whole lot of airflow. Now I'm starting to think that the register we are using in that room is not a good one and is restricted some of the flow. What do you think? I posted a picture of the register in one of my early posts on this thread.
Perforated diffusers like the one in your game room tend to have a horizontal throw, so most of the warm air will hug the ceiling. A louvered or step-down diffuser like you have in the theater room may work better for you. Or you might try removing the 4 pattern deflectors (more vertical throw) and seeing if that helps first.
I'm having a contractor come out on Wednesday to inspect the WHOLE system, and also to perform an energy audit on the house. I have always wondered this, but never mentioned anything about this in the past on this thread, but specifically what part of the duct work looks terrible?
PS. when I first started this thread I meant for the title to say "Will another return be helpful for basement system" not "Should a return".