Air Conditioning Buying Guide

Buying air conditioning used to mean one decision: how many tons. Today you also choose between central split, packaged, ductless and ducted mini split systems, single-stage and inverter compressors, an air handler or a furnace indoors, and the new R-32 and R-454B equipment replacing R-410A. This page covers each choice briefly and links to the collection and detailed article for each.

The quick answer: Most US homes with ductwork are best served by a central split system, an outdoor condenser matched to an evaporator coil on a gas furnace or in an air handler, sized by a Manual J load calculation (not square footage), rated at or above the regional minimum of 13.4 SEER2 in the North or 14.3 SEER2 in the South, and built for R-32 or R-454B refrigerant. Homes without ducts, additions and single rooms are better served by a single-zone or multi-zone ductless mini split. Pick an inverter model for humidity control, quiet and lower bills. Central systems last roughly 15 to 20 years; when the compressor fails on a unit that age, replacement usually beats repair.

System types

• Central split system. Outdoor condenser plus an indoor evaporator coil on a furnace or in an air handler, connected by a line set and sharing the home's ducts. The standard for US houses with ductwork.
• Packaged unit. Condenser, coil, blower and optional gas heat in one outdoor cabinet on a slab or roof. Common in the South and Southwest.
• Ductless mini split, single-zone. One outdoor unit and one wall, floor or ceiling indoor head for a room or open area; no ducts, just small refrigerant lines through a 3-inch hole.
• Ductless multi-zone. One outdoor unit feeding two to five indoor heads, each on its own control. Also called a multi-head split system.
• Ducted mini split. A compact concealed-duct air handler in a ceiling or closet serving a few rooms through short duct runs: mini split efficiency without visible wall units.
• Ceiling cassette and floor console. Alternative indoor heads: a cassette recesses into the ceiling with four-way airflow; a floor-standing console mounts low where a high wall unit will not fit.

Shop AC Condensers, Mini Splits and Ceiling Cassettes, or read the air conditioning systems guide and Ducted AC and multi-head split systems.

Sizing

Air conditioners are sized in tons; one ton is 12,000 BTU per hour, and residential equipment runs from 1.5 to 5 tons. A ducted system moves roughly 400 CFM of air per ton.

The correct size comes from an ACCA Manual J calculation covering climate, insulation, windows, orientation, air leakage and occupancy; square-footage rules of thumb miss by a full ton surprisingly often. Oversizing is the common mistake: the unit cools quickly, shuts off before it has removed enough moisture, and leaves the house clammy.

Shop AC Condensers or read Find the right AC and furnace size.

SEER2 and regional minimums

SEER2 is the DOE cooling efficiency rating in force since January 2023. Its test uses higher duct static pressure than the old SEER test, so SEER2 numbers run slightly lower for the same unit. Minimums for split-system air conditioners under 45,000 BTU/h are regional:

• North: 13.4 SEER2
• Southeast and Southwest: 14.3 SEER2 (the Southwest also sets EER2 minimums)

Split heat pumps are 14.3 SEER2 nationwide and packaged units 13.4 SEER2 nationwide. Each step up saves energy, but payback depends on how many cooling hours your climate has.

Shop AC Condensers or read the USA SEER2 guide.

Inverter vs single-stage

A single-stage compressor is on or off: lowest cost, simple to diagnose, fine in dry or mild climates. Two-stage units add a low-capacity step for longer, gentler cycles.

An inverter (variable-speed) compressor ramps from roughly a quarter capacity to full to match the load. Long, low-speed cycles pull more moisture from the air, hold temperature within a degree and run quieter. Virtually all mini splits are inverter-driven; in central equipment, Goodman, ACiQ, York and Daikin all offer inverter condensers.

Shop AC Condensers or read the air conditioning systems guide.

The refrigerant transition

Under the EPA's phase-down of high-GWP refrigerants, new residential air conditioners and heat pumps moved from R-410A to lower-GWP alternatives starting in 2025. Most manufacturers chose R-454B; Goodman and Daikin chose R-32. Both are mildly flammable (A2L) refrigerants, and an R-410A indoor coil cannot be paired with an R-32 or R-454B condenser.

Existing R-410A systems remain legal to run and service, but when an R-410A compressor fails the matched replacement is now a complete R-32 or R-454B system, not a condenser swap.

Shop AC + Coil Systems or read R-410A equipment discontinued: replacement options.

Air handlers vs furnaces

Every ducted AC needs an indoor blower to move air across the evaporator coil. If the home has gas, that is usually the gas furnace with a cased coil on top. If the home is all-electric, or the condenser is a heat pump, you use an air handler: a cabinet with blower and coil built in, with optional electric heat strips.

Either way, the blower's airflow at your duct static pressure has to cover the coil's tonnage; a 3-ton coil on a 2-ton blower will freeze up.

Shop AC + Furnace Systems, AC + Air Handler Systems, Air Handlers and Ducted Air Handlers, or read Air handlers explained.

Lifespan and when to replace

A central air conditioner typically lasts 15 to 20 years, and mini splits are similar. Repair makes sense under about 10 years when the fix is a capacitor, contactor, fan motor or board. Replace when the compressor or a coil fails out of warranty, the system uses R-22, or a repair estimate approaches half the cost of a new system.

Shop AC Condensers or read How long furnaces, heaters and ACs last.

What it costs

As of 2026, replacing a central air conditioner in the US (condenser and matched coil, installed) typically runs roughly $5,000 to $12,000, more with a new furnace or air handler. These are rounded estimates that vary by region, tonnage, efficiency and the ductwork or electrical work involved.

Read Central air conditioner replacement cost in the US.

Accessories you need at install

• Line set in the sizes on the condenser label, long enough for the real run, with insulated suction line.
• Pad or wall brackets for the outdoor unit.
• Disconnect box, whip and breaker matched to the nameplate minimum circuit ampacity.
• Thermostat that supports the equipment's stages or communicating protocol.
• Locking caps, surge protector, drain pan and float switch, and for mini splits a line set cover and condensate pump.

Shop Installation Kits and Line Sets, or read the HVAC install prep checklist.

Brands we carry

Brand	Central split AC	Mini splits	Notes
Goodman	Single-stage, two-stage, inverter; AC + furnace and AC + air handler systems	No	R-32 on new models; broad parts support
ACiQ	Inverter condensers and systems	Yes	High-efficiency ducted systems
MRCOOL	No	DIY, Universal and Olympus; single and multi-zone, cassettes, ducted and floor units	Pre-charged DIY line sets
York	Yes	No	Contractor-grade central equipment
Guardian	Yes	No	Value central systems
Daikin	Yes	Yes	Inverter specialist; R-32

Shop Goodman, ACiQ, MRCOOL and Daikin, or read the air conditioner brands guide.

FAQ

What SEER2 rating should I buy?

At least the regional minimum (13.4 North, 14.3 South for split ACs). Going to 16 to 18 SEER2 pays back fastest in long cooling seasons; in short seasons spend the difference on correct sizing and good ductwork.

How long does a central air conditioner last?

About 15 to 20 years with annual coil cleaning and regular filter changes. Compressor failure after year 12 is usually where replacement wins.

What is a ducted AC unit?

Any system that delivers cooled air through ductwork: a conventional central split, a packaged unit, or a ducted mini split with a concealed air handler.

Will my old R-410A coil work with a new condenser?

No. New condensers use R-32 or R-454B and must be matched with a coil designed for the same refrigerant.

Shop at HVAC MORE

Browse AC Condensers, AC + Furnace Systems, AC + Air Handler Systems and Mini Splits, or use the system builder to pair a condenser with a matched coil, furnace or air handler. Contact us if you want a second opinion on sizing.