16 year old house on slab, split level, thermostat mid way up stairs. Master bedroom gets REALLY hot but the living areas stay cool or even COLD. Damper (is that what it's called??) on the fireplace not tight, air comes through, fireplace in "bonus" room (basically area under the stairs going up and under the bedrooms on the front of the house). Toe kick (is that what that is called???) at bottom of kitchen cabinets does not meet the bottom of the cabinets, air comes in. Windows leak. Yep, I've got a lot of work to do! Any suggestions to get me started?