It's about the room over the garage that just won't co-operate. You rechecked the heat
loss, gave it a little extra, took extra care insulating the trunk line, but the room is
still cold. The cooling worked okay last summer, but it just won't heat right. How come?
Location, location, location!
It isn't a situation of heat loss, but of heat gain. The other second floor rooms are gaining
heat from the room below. The air temperature of the first floor ceilings can easily reach
into the eighties, and the air going up the stairways can also be this warm. Both sources
of heat reduce the demand of the second floor. Except of course that room over the garage.
The room over the garage is losing heat from below instead of gaining. It is an island in
the cold with one small bridge, the doorway, connecting it to the main house. Extra outlets
won't help. They only function when the system is running, when the thermostat calls.
That playroom in the basement has the opposite problem. It heats fine, but when the cooling
comes on, It's freezing down there. Sometimes, it even needs heat when the upstairs rooms
are calling for cooling. How come? Again, location. In this case, it's a situation of heat
loss all year long. Even in the summer, especially in spring, this room has a heat loss
that is usually ignored in calculations.
Both rooms, the room over the garage and the room in the basement, are victims of reverse
heat loading. Reverse heat loads are gains or loads that were assigned heat transfer values
of zero during calculations instead of being assigned a negative factor.
When the heat gain of the basement was calculated, the floor was given a heat gain value
of nothing, because it does not gain heat. That is correct, but inaccurate. The floor in
fact loses heat, even during the cooling season.
The best solution in both cases is to isolate these areas by zoning. A special control
panel can alternately supply heat to the basement from the same system that provides cooling
to the floor above it.