I replaced all of my 50 Watt GU10 Halogen Fixtures with $9 LEDs... 6 Watts each, Amazon has them for like $6.50 and up.

I would prefer having original suppy on opposite wall.

You need to double check the returns for your home. I assume you have at least 3 strategically located.

For new system, you should consider a whole house pleated filter media cabinet.

Insulation qualities should be checked for possible improvement. I would install good DP windows.

IMO

Thank you so much for the replies.

The lighting will remain halogen in that room for reasons that are unimportant here, however I appreciate the suggestion.

We do have good double pane windows throughout house, better than average construction with lots of insulation and well-insulated ducts.

There are four returns spaced through the rambler. The only issue we've had is the one room. We have an identical bedroom at opposite end of hall that has one supply and is serviced by the same return. It's climate is just fine.

We do already have an electronic air cleaner in the system, can you tell me why the suggestion on the media cabinet concerning the problem with this room specifically?

I was thinking the same thing about the Supply location. It looks (to me) like supply air would have ran down the one wall (before wall was taken out) and up to the return before filling the room. I am concerned that now that the wall is gone that the two supplies are close together, and that if my assumption was correct, then the same thing will happen unless we change something.

Our first idea was to move the supply, as you suggested, to the opposite wall. Should we also consider a return inside the room?

Thanks again for your thoughts.
Connie

I think the original bedroom should have had two supplies. I would add a second supply in the lower left hand corner near the windows. If that is not possible then put the supply along the wall on the left close to the closet.

The new expanded room has 6 windows. That is a lot of glass area. You may need a fourth supply in the upper right hand corner.

The halogen lights don't factor into the calcualtion for heating. You may want to add the heat produced by the lights for the cooling calcualtion.

My suggestion on the filter cabinet had nothing to do with room addition.

You just need one and if happy can certainly reuse existing.

Make certain new supply is sized correctly and old supply as well if relocated.

I see no real reason to add a return to this room as long as return outside room is functioning.

IMO

Thanks to everyone for the suggestions. This is a DIY project we wanted to get done because we are ready for flooring in there. We ended up moving one vent to the opposite side, like shown below. It's the same duct type and the same supply so hopefully this messed with the overall system the least. Also, this new drawing better shows the location of the second vent. Somehow I had that off a bit above -- it is actually centered between the windows.

We hope that this will be enough to improve things. IF NOT, it will be simple to reopen the floor where the first vent was, which would create three supplies. IF for whatever reason that didn't work we would then add a Return...IF that didn't work, I guess we'd have to move! LOL When we do have an HVAC contractor replace the heating system we'll be sure to show him what we've done.

P.S. As for the media/filtering...we are considering replacing the electronic filter with the big paper type.

Thanks again!
Connie

I'm curious as to why you closed the original supply vent.

I would have centered the relocated vent.

IMO

Since the remainder of the house is balanced well, and since there seems to be no problem with the ducting or supply air to the room, simply changing the dynamics of the airflow through the space seems the most conservative approach in our opinion. If we had chosen to add one, or two additional supplies, we do not know what the impact would be to the remainder of our system. That additional supply would be coming from somewhere else and there is only so much pressure to go around. If the concept weâÂÂve chosen doesnâÂÂt work out then it is simple to start robbing Peter to pay Paul by reinstalling the original vent while hoping that we donâÂÂt find the opposite end of the house suddenly too cold/warm.

We chose the new vent location to one side because the space will be a bedroom again someday. That wall is the most likely place for a bed. The chosen location keeps the vent out from underneath even king size.