I have a two units in my 3600 SF house, one w/ 4 tons for 2400sf and the new one about to be installed for 2.5 tons covering the bedroom section. In hindsight, the Trane XR12 has proven inadequate for the 2400 sf section with west view. It should have a 5 ton but too late.
The suggestion was, while we are putting in the 2.5 ton for the bedroom section, covering 1150 sf, let's run a new supply to the under served area of the house that the 4 ton unit serves. The thought is, during the very hottest days, the extra air that is being produced by 2.5 ton unit can be pumped into the room where the temps tend to creep during the summer. It appears the 2.5 ton unit can comfortably support the extra supply, so why not send the air to a place where you need it.
This sounds odd in a way, but on the other hand, it may prove to be a terrific solution. Given the uniqueness, I wanted your opinion. I asked what happens if the extra air flow is needed for the back of the house and he said worse case, you can close the vent down or off. Sounds interesting but pls weigh in.