Before putting an AC machine into service, make sure its duty rating matches the application requirements. Otherwise, there’s a good chance excessive heat will degrade the machine’s windings.

Kristin is a lead editor at Forbes Home and has nearly a decade of professional experience as a writer and editor. She's previously worked at sites like Talking Points Memo, Insider, Delish, Angi and ...

Here’s how it works: Multiply the age of the equipment by the estimated repair cost. If the result is higher than $5,000, replacement is probably your best bet. If it’s lower, you might do better to ...