Yes, a two stage central air conditioner can be worth the extra money in terms of energy cost savings and humidity control.
This is especially true in warm and humid climates and for homeowners who want the lowest possible energy bills.
Did you know? Two stage air conditioners might last longer – not just give higher efficiency and humidity control. The reason two stage central air conditioners might be more durable is that some are built with better components, like a high quality compressor, compared to the cheapest single stage ACs. Not all single stage models are poor quality, but most brands make some cheapies to attract budget-conscious consumers.
What’s On This Page
This page compares the benefits of a two stage AC vs single stage, extra cost, best brands and recommendations by state – yep. We’ll give our pro recommendation considering the climate of each state.
What is a Two Stage Air Conditioner?
It’s about the compressor – the part of the system that compresses refrigerant and effectively pumps it through the system.
A two stage or 2-stage air conditioner has a compressor that has a low speed and a high speed.
Low stage: The compressor runs at 60% to 70% of capacity depending on the model. The advantages are quieter cooling, better humidity control and higher energy efficiency and cost savings. Why is low better for humidity? Low stage produces longer cycles that move the air over the cold indoor coil for a longer period of time, so more moisture is condensed onto the coil and drained – removing it from the air in your home.
High stage: The compressor only runs at full blast, 100% capacity, when, 1). It has to because the outside air is really hot and the temperature is rising, so it needs all its power to keep up with cooling your home, or 2). You adjust the thermostat down by several degrees. On a warm day, if the thermostat is set to 76 and you turn it down to 72, the AC will probably run on “high” or 100% to cool the house by 4 degrees. Under normal circumstances, the high stage of air conditioning is only needed 15% to 25% of the time.
By contrast, a single stage AC compressor runs at 100% all the time during the cycle. Let’s look at more differences between single stage and two stage air conditioners. Here is an overview of how Lennox two stage air conditioners work.
Single Stage vs Two Stage AC
We’ve said that a two stage compressor has advantages over a single stage in terms of climate control and possibly efficiency. We say “possibly,” because there is an overlap at 16 and 17 SEER. You can buy a 16 or 17 SEER AC in either single stage or two stage versions.
But the 2 stage AC always costs more. This chart shows the differences when you compare single stage vs two stage AC models.
|Efficiency||Humidity Control||Cost Range|
|Single stage||13 - 17 SEER||Average||$3,600 - $7,400|
|Two stage||16 - 20 SEER||Average & Better||$4,400 - $10,000|
Cost Difference Between Single Stage And Two Stage AC
It’s pretty easy to compare the cost of two stage AC vs single stage AC models. You can compare apples to apples, for example two 16 SEER units. Or you can compare all single stage ACs in the 13-16 SEER range to all two stage ACs, which fall into the 16 to 20 SEER range.
We do both.
16 SEER single stage vs two stage air conditioner cost:
Two stage ACs cost $650 to $1,000 more than a comparable single stage AC depending on the brand, model and size. For example, here are price ranges for Goodman vs Lennox single stage and two stage central ACs from 1.5 tons to 5.0 tons:
- Goodman 16 SEER single stage AC installed: $3,600 – $6,000 based on size
- Goodman 16 SEER two stage AC installed: $4,400 – $7,000 based on size
Price difference: $800 – $1,000
- Lennox 16 SEER single stage AC installed: $4,300 – $6,900 based on size
- Lennox 16 SEER two stage AC installed: $5,100 – $7,600 based on size
Price difference: $700 – $800
Those are prices for ACs with the same SEER rating.
All single stage vs two stage air conditioner cost comparison – 13 SEER to 20 SEER:
The most expensive 18 to 21 SEER two stage models can cost $1,500 to $3,000 more than 13-16 seer single stage models.
- Lennox 14 SEER single stage AC installed: $3,500 – $6,000 for 1.5 to 5.0 tons
- Lennox 20 SEER two stage AC installed: $5,700 – $8,800 for 1.5 to 5.0 tons
Price difference: $2,200 – $2,800
Is A Two Stage Air Conditioner Worth It
YES: If your climate is warm – and especially if you have high humidity – yes, consider upgrading to a 2 stage AC. You will enjoy drier, more comfortable air and you will see cost savings on energy if the two stage unit has a higher SEER rating than the single stage AC you compare it with. Regions of the country prone to high humidity include the South, Southeast, Northeast and Northwest. Parts of the Great Lakes region can be pretty sticky too.
What about in hot, dry climates? If you live in the Southwest or eastern side of the Rockies where parts are considered high mountain desert, then you might want a two stage unit for the higher efficiency, if you choose a 17 SEER or higher rating.
NO: If you live in a northern climate where you don’t use a lot of air conditioning, then no. You will waste money buying a two stage AC.
A 2-stage AC is also worth the extra cost wherever you live if ecofriendly air conditioning is important to you. Consider buying the most efficient 2-stage unit you can afford. Most are 18 SEER, but there are a couple with SEER ratings as high as 20 or 21. The Lennox XC21 AC is 21 SEER, for example.
Recommendation by State
Here are general answers for each state with a few notes where applicable.
|States||Worth it or Not (Yes, No, Possible)|
|California||Yes in southern Cal; less important in northern & central|
|Arizona||Yes - especially for efficiency|
|Pennsylvania||Yes for humidity control if desired|
|Colorado||Possibly in non-mountainous regions of SW CO|
|Connecticut||Nice to have for humidity, but not essential|
|Delaware||Nice for humidity control|
|Illinois||Nice to have in southern part of the state|
|Indiana||No in northern IN, possibly in southern IN|
|Kansas||Possible - Yes, if you want high efficiency cooling|
|Kentucky||Yes, except in the mountains|
|Massachusetts||Possible - if you want better humidity control, yes|
|Michigan||Possibly only in southern MI|
|Minnesota||Possibly for the efficiency during heat waves|
|Nevada||Yes for efficiency in hottest areas|
|New Jersey||Yes, if you want better humidity control|
|New Mexico||Yes in hottest parts of the state|
|New York||No in upstate NY, possible everywhere else|
|North Carolina||Yes - preferred for heat and humidity control|
|Ohio||Possible, especially in southern OH|
|Rhode Island||Possible - preferred but not essential for humidity control|
|West Virginia||Possible - preferred|
Calculate Savings with a Higher SEER 2 Stage AC
We’ve got a good way to compare air conditioners based on efficiency and your local climate and energy costs. The exclusive Pick HVAC SEER Savings Calculator allows you to plug in 2 different SEER ratings to show how much energy savings you’ll enjoy with the more efficient unit. You can also choose your state, and local electric costs will be used for the calculation.
Is Variable Speed AC A Good Upgrade For Two-Stage AC?
In our opinion and the opinion of most AC technicians, it is rarely a cost-effective upgrade to choose a variable capacity aka variable speed air conditioner over a two stage air conditioner.
Only if your climate is quite hot and/or very humid – or if you put a premium on indoor climate control and lower energy costs is upgrading to a variable speed AC worth it.
Top Two Stage Air Conditioners
We’ve selected a handful of the very best two stage central air conditioners on the market. They rate high in reliability and homeowner satisfaction.
The table below shows installed costs for the whole range of sizes.
Top Two Stage Air Conditioners
|Trane||XR17||2-5 ton||18||$7,650 - $10,300|
|Lennox||XC21||2-5 ton||21||$8,200 - $11,000|
|Carrier||24ACB7||2-5 ton||17||$7,400 - $9,900|
|Goodman||GSXC18||2-5 ton||19||$5,400 - $8,400|
|Rheem||RA17||2-5 ton||17||$6,950 - $9,200|
|Bryant||127A||2-5 ton||17||$7,250 - $9,700|
Do I need a two-stage thermostat for a two-stage air conditioner?
Yes. To take advantage of the two stage compressor, you must install a two stage thermostat.
How do I know if the air conditioner is one stage or two stage?
There are a few ways.
1). Listen to it run at different parts of the day like in the morning when it isn’t super-hot outside and then again in the warmest part of the day. Does it seem to run louder or more powerfully during the hot part of the day? That’s a sign of it having two stages. Or turn the thermostat setting down by 4-6 degrees, and see if it runs louder than normal.
2). Check your owner’s information – which we assume you’ve already done. It should list the model number, size and number of stages.
3). Search the brand name and model number online, and you should find the information. The model number is found on a tag on the jacket of the outside condensing unit. For example, try searching Rheem RA1624AJ1NBRHC, and you will see that this is a Rheem 2 Ton 16 SEER Single Stage AC.
What happens if you only use the high stage of a two stage air conditioner?
The only way this would happen is if the AC is much too small for the application and it always needs to use the high stage to keep up with the cooling demand. It’s rare, but if this is happening, have an HVAC technician evaluate the system. It is also possible it needs maintenance or a good cleaning of the coils. And check your air filter – a dirty filter reduces air flow and makes an AC run on the high stage more than it should.