Heating and cooling systems fail in predictable places — the parts that move, the parts that carry refrigerant, and the parts exposed to outdoor weather. Most bills come down to one of a handful of components.
Pick a task and a state — the band already has the local cost index applied, the same way it's calculated everywhere else on the site.
National baseline, before your state's regional index. Use the calculator above for a state-adjusted number, or browse by state.
Most hvac bills trace back to one of these — knowing the typical lifespan is the difference between an expected replacement and a surprise.
The most expensive single part in the system — often cheaper to replace the whole unit once it fails out of warranty.
Sits outside, exposed to heat and debris; the single most common repair call.
Prone to slow refrigerant leaks as it ages, especially in humid climates.
Runs constantly during heating and cooling season; wears from duty cycles, not calendar age.
A small, cheap part — but its failure is the #1 reason a unit won't start at all.
Often replaced sooner for smart-thermostat features rather than failure.
Leaks here don't stop the system — they just quietly waste the energy it's already paid for.
The common ways these systems fail, in the order they tend to show up.
The unit hums but won't start, or the fan runs without cooling. Cheap part, common call, usually a same-day fix.
Slow leaks from aging coils or line connections reduce cooling capacity gradually — often mistaken for "the unit just isn't as strong anymore."
Dust, debris, and constant heat cycling wear the bearings until the motor seizes or draws excess current.
Reduces efficiency long before it causes a breakdown — the cheapest problem to prevent and one of the most common to ignore.
Reads the wrong temperature, causing short-cycling that accelerates wear on everything downstream.
Worth knowing before you agree to anything — what's actually happening in the system, and why the market around it prices the way it does.
The Science
One ton of cooling equals 12,000 BTU/hour — the rate needed to melt a ton of ice in 24 hours. A 3-ton system moves 36,000 BTU/hr of heat out of the house; it doesn't create cold, it relocates heat.
A system that's too big satisfies the thermostat fast and shuts off before it's pulled humidity out of the air — leaving a house that's cold and clammy, with extra compressor wear from short-cycling.
It evaporates indoors, absorbing heat, then condenses outdoors, releasing it. A system running even slightly low on charge loses capacity out of proportion to how "low" it sounds.
Undersized returns starve the blower motor. A well-installed system on bad ductwork can underperform an average system on good ductwork — the ducts are half the equation.
The Economics
EPA Section 608 certification is legally required to handle refrigerant — which is why a coil leak repair and a thermostat swap sit in completely different price tiers.
A fixed number of certified techs against a seasonal surge in calls pushes price and wait time up together — it's triage, not price gouging.
The same model number can carry a different cost at different shops depending on their distributor tier — exactly the kind of opacity a public price index exists to expose.
The same six-input breakdown published on every hub — parts, labor, overhead, and margin, not hidden behind a single number.
Roughly ten percent goes to shop margin — what a good shop clears to still be answering the phone the next time you call. See the full methodology for how every input is calculated.
Submit the invoice — no account, no name, no contractor named — and help sharpen this hub for the next person who looks it up.