I recently had central air installed at Casa Kedrosky. It’s a fat R2D2-ish looking Trane thing, with a new blower, etc.
The trouble is, the system blows prodigious, wind tunnel-esque amounts of cold air to two downstairs vents. It cools the downstairs so damn fast that you can nearly make ice cubes on the downstairs floor while the upstairs is still balmy.
I called the installers back and told them we needed to rebalance the air flow. Bringing the downstairs to 15 C just so I could get the upstairs to 25 C didn’t strike me as a good idea. Here’s the ensuing discussion:
Paul: So, how can we fix this? Is there some way to cut the air flow downstairs? It’s literally strong enough to part your hair.
Installer: We could turn down the blower. That would reduce the air flow.
Paul: But wouldn’t that cut air flow everywhere?
Paul: Well, that would make it slower to cool the whole house, and the downstairs would still cool way faster than upstairs.
Installer: That’s true, but it wouldn’t blow so hard downstairs.
Paul: Right, but it’s not the blowing alone that’s the issue. It’s the big difference between upstairs airflow and downstairs airflow that makes it so much colder downstairs.
Installer: Okay. Well, my recommendation would be to move the thermostat. We could move it to the stairs from the kitchen.
Paul: Why would we do that?
Installer: Well, if the downstairs is cooling too much, moving the thermostat somewhere else would help bring that to the right temperature.
Paul: I don’t get that. Why don’t I just lower to whatever temperature with the thermostat here in the kitchen that gets me to the temperature I want elsewhere in the house? What difference does it make where the thermostat is, it’s all relative.
Installer: No, no. If you want a lower temperature upstairs, you should put the temperature sensor there.
Paul: No, that doesn’t make sense. If I put the sensor upstairs and lower it to 22 C, then that’s still going to lower the downstairs temperature to 15 C or so. That doesn’t change anything in terms of the unbalanced air flow.
Installer: We’re moving the thermostat though. It will pick up the upstairs temperature.
Paul: It doesn’t change anything. The furnace doesn’t change its behavior because of where we put the sensor. It doesn’t change anything because it is being observed; this isn’t Schrodinger’s thermostat.
Paul: Never mind.