I've been searching for an answer to this question but have yet to find one that applies. I'm looking to put in a new thermostat on the 2nd floor where the bedrooms are that would take over in the summer to keep the rooms cool enough to sleep. The original thermostat is on the first floor and keeps the whole house warm enough in the winter. I'd prefer not to have to go into the walls and do crazy new duct work/rewiring. The house is my first home and was a foreclosure so I already have my work cut out for me and would like to get as simple of a fix as possible.
I would love for the new thermostat to be wireless and just able to communicate with the old already wired thermostat to tell the AC when to turn off and on again. Is this type of product out there? Or do I need to bite the bullet and re-wire/re-duct the whole house? I've looked into covering the registers but I've heard that can make the furnace/AC unit less efficient so would like to avoid that as well. There are no ducts towards the ceilings on the 2nd story. I've already ordered a new high-efficient roof in order to help with the heating/cooling issue, and am planning on putting new insulation in the attic when I get the chance. But with summer coming on I'd really like a quick fix if it's available.
Thank you all for your help!