Just bought a house? Here's when to expect the big HVAC bill.

Buying a home is a major financial step, and for new owners, unexpected repair bills can quickly rival mortgage payments. Heating and cooling systems are frequent culprits for these surprise expenses. Unlike cosmetic upgrades, a malfunctioning HVAC system demands immediate attention and funds.

Many new homeowners are unaware of when these costly repairs are most likely to occur. A home inspection can reveal a system's current condition but cannot predict its precise failure point. Generally, HVAC systems don't break down suddenly. Instead, they become less dependable and costlier to maintain over time, eventually necessitating replacement.

New homeowners who purchase houses with HVAC systems that are 12 to 15 years old or older should anticipate potential major expenses within the first one to two years of ownership. Although many furnaces and air conditioners can last 15 to 20 years with proper upkeep, advanced age inherently increases the risk of expensive repairs. Even if a unit passes a home inspection, it might still require significant repair or replacement soon after.