I am working on finishing my basement and was hoping to get a little bit of clarification on the HVAC. The basement HVAC was completed by the originally home builder, but I just want to make sure the install is acceptable once the basement is finished.
House is located in Wichita, KS and was built in 2010. Upstairs is 1200 sq ft and open to the basement which will be 900 sq ft with family room, 2 bedrooms and bathroom. Basement is completely below grade with 8 ft ceilings. There is a Ruud 80% furnace rated at 75,000 BTU and a hot water heater rated at 40,000 BTU.There are 6 3x8 supply runs with one to each room and 3 to the family room.
Return air questions:
There is only one 14 x 14 return air vent in the basement ceiling currently located about 8 ft from the furance room.
1) My understanding is that return air vents should be at least 10 feet away from combustion sources. My plan is to move this down the hallway another 10 feet so it is located at the edge of the family room and about 20 ft away from the furnace.
2) Is only one return air vent for the whole basemenet ok? I wanted to add returns to each bedroom, but I have floor trusses that are very full near the utility area and this would be very difficult without adding any bulkheads.
3)According to the builder's foreman there plan was to have me add grills to the furnace room door (when it gets installed) to provide indoor combustion air. From my readings I am concerned that my house is considered a "unusually tight construction" since it was built in 2010. I do have a 5" fresh air line going straight into the return vent near the furnace. I understand that fresh air and combustion air are different, but I didn't know if maybe this makes my house not be unusually tight.
4) We are also hoping to add a ventless fireplace to the basement at some point in the future and while our house has enough cu ft according to the calculations I just have an uneasy feeling about these systems and was wondering if anyone has had any problems with them.
Sorry for the long post and thanks in advance for your help.