When to Choose a Single Stage Air Conditioner – Advantage of Single Stage ACs
Choose a single stage air conditioner when:
- Efficiency up to 17 or 18 SEER is enough for you
- You’re not overly picky about a little extra noise or minor temperature swings of 1 or 2 degrees
- You don’t need advanced humidity removal / your climate isn’t super-humid
- Lower cost is a high priority both for equipment and for potential repairs
That is your answer in a nutshell. The rest of this post discusses these important single stage air conditioner topics with pros, cons, cost differences between single stage and two stage ACs and the highest SEER single stage air conditioners for each brand.
What is a Single Stage Air Conditioner?
We’ll make this brief, because you likely already know the basics.
Performance: Single stage air conditioners run at 100% capacity, or “full speed,” whenever they are on. Their compressors have one stage rather than low/high like a two stage air conditioner.
Airflow: They are typically supported by fixed-speed blowers in the air handler, so when the blower comes on, it’s “full blast,” which makes it “full noise” too.
Pros and Cons of Single Stage Air Conditioners
There are times when a single stage AC is a very good choice and times when you’ll be happier with a two stage unit.
There are important reasons to consider a single stage air conditioner for your home.
They cost less – Single stage central ACs cost $500 to $1,000 less than comparable two stage units. For example, we recently priced a 3 ton Goodman 16 SEER AC at $4,800 for the single stage vs $5,600 for the 2 stage unit, a difference of $800.
The difference for the Lennox single stage vs two stage AC was $5,500 vs $6,300, a $700 difference.
Those are installed prices.
Lower costs on major repairs – One HVAC installer says what every industry pro knows – single stage air conditioner repairs cost a lot less when a major part fails.
First, single stage compressors are less complex, and so they cost less than two stage and variable capacity compressors. Makes sense, right?
Secondly, single stage compressors can be replaced with universal parts while two stage compressors are usually proprietary items that must come from the brand manufacturer. That means they generally cost more.
Repairs might be faster – Most HVAC service trucks are stocked with universal single stage compressors. Whether it’s a Trane, Carrier or Goodman – or whatever brand – that breaks down, that single stage compressor will probably work on it and get your AC up and running again.
But if it’s a two stage compressor, it is usually a proprietary part made by the manufacturer with no universal replacement. The part usually has to be picked up at a parts warehouse causing a short delay or ordered – causing a delay of several days to a week or more.
Efficiency can be pretty good – The table below shows that most brands make single stage central air conditioners with certified Energy Star efficiency. The most efficient single-stage models are made by Johnson Controls brands Coleman, York and Luxaire at 18.5 SEER.
Quality tip: Johnson Controls brands are not highly respected for quality. In fact, they are among the lowest-rated brands. We do not recommend them.
Think twice about buying a single stage AC if you’re concerned about these disadvantages in very hot and/or very humid regions of the US.
Less efficient – While 17 to 18+ SEER is Energy Star-level efficient, the highest SEER central air conditioners are 25+ SEER. Lennox sells a 28 SEER variable capacity AC. If your climate is brutally hot much of the year, and you want to control energy costs, upgrading to a two stage AC might make sense.
Less comfortable climate control – Because single stage air conditioners run full speed when on, their cycles are shorter. Boom, they come on, cool down the air, and shut off until the heat rises significantly again. Then the cycle repeats. The problem is that the cycles are too short to remove a lot of humidity.
Cooled air that is humid feels clammy. No thanks! That can happen with a single stage air conditioner. Weather can be terribly humid in parts of the US. So, if that’s true where you live, consider a two stage AC.
The Most Efficient Single Stage Central Air Conditioners
Are you in the market for an efficient single stage AC?
The major brands have focused on energy efficiency in the last decade, and it shows in the SEER ratings of 17 and higher for single stage air conditioners.
Here are leading brands and their most efficient single stage central AC.
Most Efficient (Highest SEER) Single Stage Air Conditioner by Brands
|Carrier||24ACC6 & 24ABC6||17 Seer|
|Lennox||EL16XC1 & ML14XC1||17 Seer|
|American Standard||Silver 16||17 Seer|
According to the table, there are two models with 17 SEER efficiency, the 24ACC6 & 24ABC6.What is the most efficient single stage air conditioner Carrier makes?
Trane most efficient single stage AC?
Trane’s XR16 has a 17 SEER efficiency rating.
Does Goodman make a 17 SEER single stage air conditioner?
No. Goodman’s most efficient single stage AC is the GSX16 with a 16 SEER rating.
Is Single Stage Air Conditioner Loud When Running
See the table below for the quietest single stage air conditioners from each major brand.
But first, an answer to the question – is a single stage AC loud when running?
The short answer is – Yes.
Because the units run at 100% capacity whenever on, then yes, single stage air conditioners run at “peak noise” all the time.
Both 2 stage and variable capacity air conditioners can run at 100% too.
Buyer beware! Cheap = Loud. Keep this in mind if noise is a big factor in which AC you choose. The cheapest single stage AC units from each brand are the loudest.
To keep costs down, the manufacturers spend almost nothing to dampen the sound. No sound blanket. No insulation inside the cabinet to quiet them. Just let them rip – and noise can reach the mid to upper 70s in decibels. As just one example, and it’s not worse than the loudest from most other brands, the Luxaire TC3B18 tops out at 77 decibels.
2 stage ACs: They run on the lower stage or speed most of the time, which is about 70% speed, which is quieter.
Variable capacity ACs: They have a different kind of compressor – an inverter compressor. And those compressors are naturally quieter than single stage compressors. Variable capacity compressors peak in the 50s decibels but can run as quiet as 30dB or quieter.
We’ve listed the quietest single stage ACs for you.
It is a list you won’t find anywhere else – unique research from Pick HVAC.
A few details follow the table.
Quietest (Lowest Decibels) Single Stage Air Conditioner By Brands
|Trane||XL16i||69 dB||17 Seer|
|Carrier||24ANB6||66 dB||17 Seer|
|Lennox||EL16XC1||71 dB||17 Seer|
|Goodman||GSX16||72 dB||16 Seer|
|Rheem/Ruud||RA16||70.7 dB||16 Seer|
|Bryant||124ANS||66 dB||14 Seer|
|Coleman||TF4||70 dB||16.25 Seer|
|Amana||ASX16||72 dB||16 Seer|
|Payne||NH4A4||66 dB||14 Seer|
|Armstrong||4SCU14LB||72 dB||16 Seer|
|American Standard||Silver 16||71 dB||17 Seer|
|Heil, Tempstar, KeepRite, Arcoaire, |
|NH4A4||66 dB||14 Seer|
|Ducane, Concord||4AC16L||73 dB||16 Seer|
It is a tie between the Carrier 24ANB6 and similar models from the ICP brands – Heil, Tempstar, etc., as the table shows.What is the quietest single stage air conditioner?
When To Choose a Single Stage AC
There are times when buying a single stage air conditioner can make sense:
- When low cost is your top priority
- When your summers are fairly mild and you don’t run the AC a lot
- When you will use it in a part-time location, so again, it doesn’t get heavy use
- Your climate is fairly dry rather than humid
How to control humidity with single stage central air conditioner?
These steps will help. First are DIY options followed by things an HVAC technician can do for you.
What you can do:
1 – Turn down the thermostat two to four degrees during the most humid part of the day. Yes, you’ll be chilly, but the AC has to run longer than usual to remove more moisture.
2 – Make your home more airtight. Humid air gets in through gaps in door frames, window frames, attic air leaks, etc. You can stop those leaks with new doors and windows or house wrap during an exterior remodel. Cheaper options include weather stripping and spray foam insulation to fill gaps.
3 – Use a room or whole-house dehumidifier.
Call a pro to:
1 – Slow down the air handler fan speed. This will produce longer cycles that will remove more humidity.
2 – Clean the coil. A dirty indoor coil won’t get as cold, so not as much humidity will condense onto it and be drained away, removing it from the air in your home. This will prevent mold growth too.
3 – Install a TXV valve. A thermal expansion valve (TXV) maximizes the capacity of the coil, which also maximizes its ability to condense and remove humidity.