When your heat pump, a system that moves heat into your home in winter and out in summer. Also known as air source heat pump, it relies on a handful of critical parts to keep running. Unlike a furnace that burns fuel, a heat pump moves heat using refrigerant and electricity—so when one part fails, the whole system struggles. Most people don’t realize how many moving pieces are inside. A single unit can have over a dozen key components, and only a few of them are likely to break—but when they do, the symptoms can look like a total system failure.
The most common heat pump compressor, the heart of the system that circulates refrigerant wears out after 10–15 years. If your heat pump runs constantly but doesn’t heat, that’s often the sign. Then there’s the heat pump capacitor, a small but vital part that gives the motor its starting boost. A bad capacitor won’t kill the whole system, but it’ll make the unit hum without turning on. And don’t overlook the heat pump thermostat, the brain that tells the system when to turn on or off. A faulty thermostat can make your heat pump run nonstop or never turn on at all—making you think it’s broken when it’s just misinformed.
Other parts like the reversing valve, fan motor, and expansion valve don’t fail as often, but when they do, the repair isn’t always simple. A leaking refrigerant line might look like a compressor issue, but it’s actually a seal or coil problem. And if your heat pump is making strange noises—grinding, clicking, or rattling—it’s usually not the whole unit dying. It’s one part wearing out. The good news? Most of these parts can be replaced without swapping the entire system. A qualified technician can diagnose which part is faulty, order the exact match, and get you back to comfort in a day or two.
You’ll find posts below that dig into real-world cases: what a bad capacitor sounds like, how to tell if your thermostat is lying to you, why some heat pump repairs cost less than others, and when it’s smarter to fix a part instead of replacing the whole system. No fluff. No theory. Just what actually breaks, what it costs to fix, and how to know if you’re being told the truth.
Replacing a heat pump compressor in New Zealand costs between $1,200 and $3,500. Learn what’s included in the price, which brands last longest, when to replace the whole unit, and how to avoid costly mistakes.
