In January 2023, the US Department of Energy introduced a new testing procedure to determine the efficiency ratings of air conditioners and heat pumps:
Seasonal Energy Efficiency Ratio (SEER)
Energy Efficiency Ratio (EER)
Heating Seasonal Performance Factor (HSPF)
The new M1 testing procedure exposes AC and heat pump units to operating conditions that are more demanding. In other words, if you carry out the old and new test for the same heat pump model, you can now expect slightly lower efficiency ratings.
HVAC manufacturers have added the number “2” to identify efficiency ratings determined with the new test. This means you will find the terms SEER2, EER2 and HSPF2 on their equipment specifications. The original nomenclature (SEER, EER and HSPF) is still being used for air conditioners and heat pumps that were manufactured before the new requirements took effect.
The US Department of Energy also increased the minimum efficiency requirements for air conditioners and heat pumps sold through the country. The updated efficiency requirements have been specified with both the new and old ratings, since there is still plenty of equipment with the previous nomenclature in the market (SEER, EER and HSPF).
Did you know? The US also introduced new federal tax credits for energy efficient HVAC equipment in 2023, covering up to 30% of their cost. As you might guess, the efficiency requirements for these tax credits are higher than the minimum nationwide requirements.
The units are divided by performance: 4 variable capacity options and 3 each for two-stage and single-stage models. Our strategy is to give you the most efficient options based on the performance level you want, as will be clear in the model reviews.
This guide is focused on the standard split system air source central air conditioners.
Each model is reviewed with the total cost installed, unit features and benefits, pros and cons, and information on how to use the AC for top ROI.
Split System Air Conditioner Options
As you shop for central ACs, considerations will include:
Size/Capacity: Residential air conditioning units can range in size from 1.5 to 5.0 tons, which corresponds to 18,000 BTU to 60,000 BTU.
Efficiency: ACs start at 13 SEER, though the least efficient from most brands are now 14 or 15 SEER. Maximum efficiency increases every year and tops out at 28 SEER with Lennox SL28XCV (024-230A) model for 2022.
SEER is Seasonal Energy Efficiency Ratio, a measurement of how effectively the unit uses electricity to move heat from inside to outside.
SEER ratings: Each model’s SEER rating is qualified with “Up to.” Why? Because the efficiency level drops slightly in larger models.
For example, the Carrier Infinity 26 offers 26 SEER in the 2-ton and 3-ton sizes, but the 3.5-ton to 5-ton models range from 22.5 to 25 SEER.
Installed Cost: Expect to pay $4,900 to about $12,500 to have a central AC installed. This includes the outdoor condensing unit, a matching coil placed in or adjoining your furnace or air handler, new refrigerant lines and possibly a new thermostat.
Average Cost: Most homeowners pay between $6,500 and $10,500 for a 3-ton, 18 SEER air conditioner with a two-stage compressor.
Cost factors are straight-forward: The central air conditioning unit’s size, quality, efficiency, performance level and the complexity of installation are the major determinants of final cost.
Let’s break down that question to find the answer:
Air source: The AC pulls heat from the air in your home and, here’s the key, releases it in the air outside.
While this is obvious, we mention it in distinction to a geothermal or ground-source air conditioner that releases the heat through piping beneath the ground or submerged in water.
As a result, air-source ACs are not as energy efficient as geothermal units. However…,
Central: This means it serves the whole house – or a large section of a very big house. The units in this list work in conjunction with an air handler, which in most homes is a gas furnace. Cooled and dehumidified air is pushed through supply ducts into each room or zone of the home. Return ductwork circulates warm, humid air back to the air handler to be “treated.”
Air conditioner: These units supply cooled and dehumidified air only. The refrigerant in the system absorbs heat indoors and carries it outside to be released. They do not have reversing valves like a heat pump, so central AC units cannot supply heat.
As noted, they DO require ductwork, unlike a ductless mini split central AC, or heat pump.
Top 10 Most Efficient Central Air Conditioners
1-4 are Variable-capacity ACs: They have compressors that operate between 40% (25% on some models) and 100%. The “speed” of the compressor modulates very slightly up or down to maintain very even indoor temperatures. They are the most expensive, most efficient and remove the most water from humid indoor air.
5-7 are 2-stage models: These units are top-sellers for their balance of efficiency, climate control and reasonable cost.
2-stage central AC units are manufactured with compressors that run at 65% of their potential to maintain your home’s comfort level. When outdoor temperatures rise quickly or you turn down the thermostat, they shift to 100% capacity to catch up.
8-10 are Single-stage ACs: Their compressors operate at 100%. They are the most affordable and least efficient. In very humid weather, they might not remove as much moisture from the air as you would like.
Remember, the list is grouped 1-4/variable capacity, 5-7/two-stage and 8-10/single-stage, so the most efficient air conditioners top the list.
Identical Brands – Most of the units in our list have a “twin” from another brand. For example, the Carrier Infinity 26 and the Bryant Evolution Extreme 26 are identical in all but the cabinet and name plate.
So, if you don’t see your favorite brand on our top 10 list, then check the Identical Models entry at the end of each Review. It might be there. Below the Reviews, we also list a who’s who in HVAC equipment manufacturers and the brands each makes.
Home and property owners like you have heard rumblings that latest central air prices are way up and are asking, “how bad is it?” This buying guide has all the details whether you are replacing an old AC or installing a new central air unit or improved efficiency.
What’s covered in this guide? Cooling Only – This guide is about adding a new central AC or replacing an old one. It does not cover the cost of a new air handler – the inside unit with a blower fan that is connected to the ductwork. If you have a forced air furnace, it doubles as an air handler to house the indoor coil and circulate air conditioned, dehumidified air.
Central AC Cost – Installed
Central air conditioners can be divided into entry-level, midrange (most popular) and premium models for the sake of discussion. Here are the latest prices and what you get for the money.
$2,700 – $4,600
$4,900 – $9,600
13 – 15
$4,400 – $9,200
$6,600 – $12,500
15 – 19
1 or 2
$6,300 – $12,700
$8,800 – $15,000+
18 – 28
2 or Variable
Yes, those are prices for just central air conditioning, plus a new thermostat if needed.