The split is a 18,000btu unit covering less than 400 square feet.
Normally 18,000 btu units are used on double that square footage. So it was never over worked, just over cycled.
The inverter split won't cycle on and off like the old fixed speed unit. It should be able to throttle down to about 6,000btu and run nice and easy.
I would have to say that part of the house is well enough insulated. I stuck an inefficient 2 year old barely used 8,000btu window air conditioner in there now and it doesn't have any trouble keeping the space nice and cool.
My central A/C has been off since Wednesday afternoon. There's no way running it for the last 2 days would have "saved electricity" or helped it last longer.
That's normal for me to leave it off for up to 2 or 3 days at a time in summer.
I will probably run the centeral some this weekend.
Last time I checked my refrigerator with a Kill-a-watt plug in meter it used about 2.5kwh a day. If it's 10 degrees hotter inside the fridge might use 2.6kwh. While it would take dozens Kwhs of air conditioning to cool off the house to save maybe a few hundred watt hours on the refrigerator....
I found the fridge used about the same amount of power in the winter (2.1kwh) or summer (2.5kwh) and that is probably mostly due to opening the freezer and fridge a lot more in the summer. The house is around 20 degrees cooler in the winter and I turn the ice maker off in the fall and don't turn it back on till it warms up.
I found that the people telling us to run our air conditioner all the time are almost always the same people trying to sell new ones or service our broken ones.
Is going to get you.