We are renting a split-level house while we are building. The HVAC system in this house has got to be the worst install ever. There are three levels: basement, first floor, and second floor. The basement and second floor are controlled by one thermostat that is located on the second floor right at the top of a wide stairwell that comes up from the first floor. The thermostat on the first floor is set at 68F, and it seems to work well and is accurate. The second floor thermostat is also set at 68F, but reads between 71F and 73F because of rising heat from the first floor. We have hung a heavy quilt at the base of the steps from the first floor to the second floor and this has helped tremendously in dropping the reading on the second floor thermostat. We have gotten it to a point where it is giving an accurate reading that is truly being realized in the rooms on the second floor. The problem I am having is that when second floor thermostat kicks the heat on, it is also heating the basement, which we never use and don't intend to use. There is one return air vent in the basement and one at the top of the stairs on the second floor. In order to conserve energy and increase air volume on the second floor, would it behoove us at all to block or partially block the return air vent or the registers in the basement? I do not have the ability to damper the trunk that feeds the basement and the second floor. We would be okay if the basement was 0F if the second floor was comfortable, and also if that would save us money in not having to heat the basement.
Thanks in advance for any help.