Lower voltage damages induction motors (mainly refrigerators and air conditioners). Higher voltage allows more load variation without the voltage going too low due to wire resistance (house and power line wire).
Thanks. I knew there had to be a reason.
You would have too drop too 105 volts or below and maintain that voltage to hurt them. Most electric furnaces are staged at about 20 amp stages. Central house A/C compressors you are talking maybe 30 amps on a 2.5 ton A/C unit. Newer heat pumps do not start under full load anyway. If my freezer or fridge comes on I don't even notice it at all. My freezer which is about 10 years old is rated for 115 volts. Meaning my lights do not dim in house. Most knowledgeable repairmen will tell you running a little low won;t hurt near as much as too high a voltage.
The largest single draw items in a house besides an electric furnace are possibly the A/C, are the clothes dryer with about a 5KW heater at 250 volts, water heater with 4.5-5.5 KW element Oven, and really thats it. Fridge and freezer are Nil too these. Heck I have an electric furnace and even at 230 my voltage inside my homes does not drop. I've worked in 2000 amp service complex around huge A/C units like a chiller that draws 1600 amps start up and 350 amps running at 460 volts. The voltage is higher so utility saves a nickle on smaller wire on their primary.