My wife and I own a two-story house with a gas-fueled hot-water radiator system and a single-story addition in the back. There's 3 radiators downstairs, 4 upstairs, and a hot-water baseboard system in the addition.

Unfortunately, there's also a 10-degree difference between the upstairs and the downstairs, and another 5 between the main downstairs and the addition.

So here's what I want to do:

Crank up the thermostat (which is downstairs) to bring up the downstairs temperature, then mostly close the valves of the upstairs radiators to keep that from getting too hot.

Will this strategy work?