I have a heating issue that Iíd appreciate some advice for. This is a long post so Iíll apologize in advance.
My home is in Western New York. It itís a Cape Cod and was built in 1950 and has forced air heating. The furnace is a 90+ condensing furnace. To help you visualize the issue the furnace is located in the SE corner of the basement and the main trunk runs along the East perimeter of the basement.
The kitchen is 12í x 14í and is heated by a 7Ē run that is approx 20í long before the register exit. This heat run is located above a drywall ceiling in a finished portion of my basement so thereís not much I can do about this run.
The heating issue is with the eating area which is adjacent to the kitchen located in the SW corner of my home. This room is 8 x 13 and was constructed over an unheated crawl space that used to be a porch. I have no idea how well floor of this area is insulated. The walls in this area have 3 Ĺ in fiberglass insulation. The windows are Andersen thermopane and are at least 20 years old (thatís how long weíve been here and they were here when we moved in). They are in good condition with no apparent leaks.
This eating area is heated by a 7Ē run that runs for ~20 feet (and contains 5 elbows) before it reaches a 7x7x6 tee which feeds one of two parallel 3 ľ x 10 ducts that run under the floor to registers on the outside (south) wall. After that tee, the run is reduced to 6Ē for another nine feet and feeds the other 3 ľ x 10 duct.
The airflow from the 2 registers served by the 3 ľ x 10 ducts in the eating area is very low and the temperature of the air seems barely above room temp. Iíve sealed the joints of the duct that I can get at with foil tape in an effort to eliminate any leaks that might be contributing to the low flow, but it didnít make much difference.
Iím thinking about increasing the size of the duct feeding these 2 runs to 8Ē if it will make a significant difference. If I do make that change, I will be able to eliminate 1 of the elbows but thatís the best I can do in that regard. I also thought about feeding only one of the two 3 ľ x10 ducts in an effort to take better advantage of the airflow that I do have but Iím not sure if thatís the best way to go.
Iíve attached a couple of photos in an effort to better explain the situation. Photo 1 is where the first underfloor duct takes off and photo 2 is from the other side of photo 1 showing the duct as it continues and connects to the second underfloor duct.
Thanks in advance for any advice and assistance.