I've searched and found some posts about this, but none have addressed our specific issue that I found.
We have a small place, only about 680 square feet. It currently has a boiler and basebard heat. It appears to have only one zone (we just bought it and are waiting on our closing) running from the bathroom on the right side in the center of the house around to the front right, across to the front left and back, then from the left rear to the right rear and back to the boiler. We think it's a closed system.
The whole back is a living room, which is an addition to the original house. That addition has some issues and we're going to be tearing up the flooring and replacing two small windows with sliding glass doors. Also, we are moving (replacing) an improperly installed wood stove and hearth. In the process we would like to go to radiant heat, since we would like to do this throughout the whole house eventually and might as well do this while we have the floors up. However with buying the place and doing the work, we won't have the money to do the entire place at once, especially considering that there is probably going to be "surprises" as we go.
So, now that you have the basics-the question is-can we do this? Will we need to have zones, or can we just bring the heat down on the baseboards? Given the size (it's also a single story), we figure that even if the baseboards are running a little cooler, the heat should still travel around from the other room to keep things reasonably comfortable.