When a furnace, air conditioner or heat pump stops working, it rarely happens on a mild afternoon. Breakdowns tend to show up during the hottest or coldest stretch of the year, when you need the system most and when repair companies are busiest. A full system replacement is among the larger expenses many homeowners face.

Regular maintenance is your best defense. Change filters on schedule, keep outdoor units clear of leaves and debris, and have a qualified technician service the system periodically. Pay attention to warning signs like strange noises, uneven temperatures, short cycling or rising energy bills, which can point to a problem worth checking early.

Some homeowners also set aside a repair fund or consider a home warranty, which may help cover repairs or replacement of covered systems in exchange for a service fee. Plans vary widely in coverage limits, exclusions and maintenance record requirements, so read the contract carefully and compare it with simply saving the money yourself.