Well, if that's the case, and it is, it's done and final. Best solution is to add new 20 amp circuit on wall bearing the existing panel to take the treadmill and planned exercise equipment and Audio visual. Just have to consider the County permit and inspection. Thanks Sparky.
Interesting to note on this build circa 2006. There are four (4) separate circuits for the kitchen.
Code requires two circuits for the countertop. The refrigerator, dining room, pantry, if there is a breakfast nook can, but don't have to, be on the same circuit but things like dishwasher, disposal, and a built in microwave can't be. Those would require separate circuits.
Yet the entire garage, laundry room (minus the dedicated dryer) , bedroom, bathroom and closet are on a single 15-amp breaker.
It's probably the laundry room lights, the 120 volt outlet for the washing machine shouldn't be on that circuit. The bathroom receptacle shouldn't be on it either. I have always put the garage outlet(s) on at least one 20 amp circuit with nothing other than the outdoor receptacles, so I don't like what they did there, but what you have really isn't that much in the grand scheme of things. You could have a dedicated 15 amp circuit feeding a duplex receptacle, plug both the space heater and treadmill into it and the breaker would have tripped. 1500 watts is over 12 amps, I don't know what a treadmill draws, but I bet it's over three.
Edited the next day to add: It's Sunday night and I just got back from an "emergency" service call for no power in the basement. The old gal was right, there was no power in the basement. The old man was watching football in the basement, got cold, and plugged in the space heater and within five minutes, there was no TV. The only things on the circuit were the receptacles in that room, and he swears the only things running were the TV, heater, and a lamp, the lights were on another circuit. On a side note, the no power in the basement was correct, as well as a bunch of the rest of the house. His wife went to the panel to check the breakers and managed to turn every single one of them on the left hand side off. She hadn't yet realized that the range and dryer didn't work as well as who knows what else, there were five single and two double pole breakers off.