We just had installed over the summer a Trane XL19. It works great in the summer time. Tonight is really the first night that we've had the heat on. We live outside of Philly PA, so the temps tonight are around 40 degrees. We have the heat pump on and I'm noticing that the air coming out of the vents doesn't feel very hot at all, and I'm checking this on the 2nd floor right below the unit. The air handler is installed in the upstairs attic. Our backup heat is baseboard hot water(oil).
So how warm should the air be coming out of the vents? Is there anything that I could check for? What's the lowest outside temperature that this should be running?