The cost of central air conditioning depends on what “new AC” includes. Replacing only an outdoor condensing unit is different from replacing a matched cooling system, rebuilding ducts, or adding central cooling to a house that never had it. Ask for the installed scope before comparing numbers.
A current manufacturer reference provides context: Carrier lists $3,000–$15,000 or more including installation. Its page also says that range excludes a furnace, evaporator coil, and duct modifications. It is a broad manufacturer estimate, not a representative national transaction dataset or a promise for your home.
Separate the outdoor unit from the complete system
Start your worksheet with the outdoor model, indoor coil, and the furnace or air handler that supplies airflow. If the blower stays, ask how the proposed combination is approved and rated. An estimate that names only the outdoor unit leaves an important comparison unfinished.
| Quote field | What to ask for |
|---|---|
| Outdoor equipment | Model, capacity, refrigerant, and staging |
| Indoor equipment | Coil model; whether the existing blower stays |
| Rated efficiency | Rating for the proposed matched combination |
| Refrigerant piping | Reuse or replacement scope and conditions |
| Drainage | Work included; protection required for the location |
| Electrical | Circuit work, disconnect, and responsibility |
| Closeout | Startup checks, permits, removal, warranties |
This is a purchasing checklist, not an instruction to inspect wiring or handle refrigerant. Have qualified contractors determine compatibility and required work.
Build a price you can compare
Consider two hypothetical proposals. These figures are original arithmetic examples, not collected quotes.
| Illustrative scope | Proposal A | Proposal B |
|---|---|---|
| Cooling equipment and installation | $6,800 | $7,400 |
| Coil included? | No; add $1,200 | Yes |
| Removal included? | No; add $200 | Yes |
| Permit included? | No; add $250 | Yes |
| Comparable total | $8,450 | $7,400 |
A lower headline became a higher comparable price. The lesson is not that bundled proposals are always better. It is that blank or excluded items must be resolved before totals mean the same thing. Real labor may be bundled; avoid adding it twice.
Ask whether sales tax is included, whether the contractor’s allowance can increase, and whether any electrical or wall-repair work is outside the contract. Get an approval process for changes rather than assuming an allowance is a fixed price.
What a higher efficiency premium buys
SEER2 describes seasonal cooling efficiency, not a fixed electrical draw. DOE’s FEMP guidance defines it in BTU per watt-hour and demonstrates climate-dependent cost comparisons. A unit that saves more in a long cooling season may have a weaker financial case where cooling is occasional.
For an illustrative upgrade, assume the premium is $1,500 and modeled electricity savings are 600 kWh per year. At an assumed $0.20/kWh, savings equal $120 annually and simple payback is 12.5 years. If the actual saving is 300 kWh, payback doubles to 25 years. That is a sensitivity test, not a forecast.
Do not apply the efficiency percentage to your entire utility bill. Water heating, lighting, appliances, and fixed service charges do not disappear when the AC becomes more efficient. Our SEER2 guide explains the comparison limits.
Capacity is a design outcome
Buying a larger unit because the old system struggled can lock in the wrong solution. The problem may involve ducts, the building envelope, or installation. ENERGY STAR warns that oversized equipment can cycle too frequently and identifies airflow as a commissioning priority.
Request a load-based equipment selection and written design assumptions. If you intend to insulate an attic or change windows, tell the contractor before selection. For capacity terminology, see 2-ton, 3-ton, and 4-ton systems.
Before accepting the proposal
Clarify scheduling, disruption, payment milestones, warranty labor, and who handles an inspection correction. Ask what happens if an existing component cannot be reused after work begins. A documented contingency process is more useful than an unrealistically precise internet estimate.
Finally, compare an AC replacement with a heat-pump option when heating is also part of the decision. Price each on the same scope. A cooling-only quote and a complete heating conversion are not interchangeable budgets, even if both include an outdoor unit.