AC installation, priced honestly

What is ac installation?

AC installation means fitting a central air conditioning system: an outdoor condenser, an indoor evaporator coil sitting on your furnace or air handler, refrigerant lines between them, and the electrical and control wiring that ties it together. A straightforward install runs one day. The two things that decide whether you are happy with it five years from now are correct sizing and installation quality - not the brand.

Signs you need ac installation

• Your current AC is 12-15 years old and this is the second summer you have paid for a repair
• The system still uses R-22 refrigerant - servicing it is now expensive enough that repairs stop making sense
• Some rooms cool and some never do, and no amount of thermostat fiddling changes it
• The unit runs constantly on hot afternoons and still cannot hold the temperature you set
• It cools, but the air feels clammy - a sign the system is oversized and short-cycling before it can dehumidify
• You are finishing a basement, attic or addition and the existing system was never sized to cover it
• You have never had central air, and window units are no longer keeping up

Seeing something not on this list? Browse hvac problems by symptom →

How ac installation actually works

1. 1

   Load calculation and equipment sizing

   A Manual J calculation works out the actual cooling load of your house - insulation levels, window area and orientation, ceiling height, air leakage, how many people live there. That number, not your square footage, sets the tonnage.

   Watch forThe phrase "we'll put in the same size you have now". Your existing unit may have been wrong from the day it went in, and a lot of homes have had the same wrong size replaced three times. Ask to see the calculation.

2. 2

   Efficiency tier and the SEER2 decision

   SEER2 is the current efficiency rating. Higher tiers cost more up front and cut running cost - the payback depends almost entirely on how many cooling hours your climate actually has. In Phoenix a high tier pays back quickly. In Seattle it may never.

   Watch forAn efficiency upsell presented without a payback calculation for your climate and your electricity rate. Ask what the annual saving is in dollars, then divide it into the price difference yourself.

3. 3

   Matching the indoor coil to the outdoor unit

   The outdoor condenser and the indoor evaporator coil are engineered as a pair. Rated efficiency assumes a matched set. Bolting a new condenser onto an old coil is cheaper on the quote and quietly costs you capacity and efficiency for the life of the system.

   Watch forA quote that replaces the outdoor unit only. Sometimes that is legitimate - usually it is a way to win on price. Get it explained in writing, including what the resulting rated efficiency actually is.

4. 4

   Removal, refrigerant recovery and site prep

   The old condenser is disconnected and its refrigerant recovered - legally required, not a courtesy. The new pad is levelled with clearance on all sides for airflow, and clear of anywhere a dryer vent or a gutter downspout discharges.

   Watch forA unit crammed against a fence or wedged under a deck. Restricted airflow raises head pressure, which raises your bill and shortens compressor life. Manufacturers publish minimum clearances; they are not suggestions.

5. 5

   Line set, brazing and evacuation

   Refrigerant lines are run, brazed with dry nitrogen flowing through them, then pulled into a deep vacuum to remove air and moisture before the charge is released. This stage is invisible once the panels go on, which is exactly why it gets skipped.

   Watch forNo vacuum pump and micron gauge on site. A quick "purge" instead of a proper evacuation leaves moisture in the system, which forms acid and kills the compressor - typically three to six years later, long after the crew has gone.

6. 6

   Electrical, condensate and controls

   The condenser needs a correctly sized circuit and a service disconnect within sight of the unit. Indoors, the coil needs a condensate drain that actually drains, usually with a secondary pan or a float switch so a blocked line does not end up in your ceiling.

   Watch forNo float switch on an attic or above-ceiling coil. It is a small part, and it is the difference between a clogged drain being a nuisance and being a drywall claim.

7. 7

   Charging and commissioning

   The charge is set by superheat or subcooling - measured, not estimated by how the line feels. Airflow across the coil is measured, static pressure is checked, and the thermostat is configured for the equipment's staging.

   Watch forNo commissioning numbers handed over at the end. Ask for measured subcooling, superheat, static pressure and delta-T on the invoice. A crew that measures will write them down; a crew that guesses will tell you it "feels good".

8. 8

   Permit, inspection and warranty registration

   Most jurisdictions require a permit for AC replacement, and the inspection is a free second opinion on your installer's work. Manufacturer parts warranties usually need registering within a set window after installation.

   Watch forAn installer who suggests skipping the permit to save money. That is your protection they are saving on, and unpermitted work can surface awkwardly when you sell the house.

What does ac installation cost?

A new central air conditioning system with installation typically lands between $4,000 and $9,000 for a normal residential replacement. Tonnage, efficiency tier, whether the indoor coil is replaced too, and any electrical or ductwork remediation are what move you within that range.

See the full ac installation cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →

Size your system with the BTU calculator → A sanity check on the tonnage you are quoted - not a substitute for Manual J.