What Is a SEER Rating?

SEER ratings explained

If you’re looking to buy a new heat pump or air conditioner, you’ll likely see different SEER ratings for each model. Even if you know SEER’s definition (Seasonal Energy Efficiency Ratio), you might be left with questions about what it really means.

What’s a good SEER number? What’s the typical range? How much more should I pay for one SEER rating over another? And why are SEER standards different in the north and south of the U.S.?

Let’s dig into SEER, a number that means well, but doesn’t explain itself properly.

What does SEER mean?

The Seasonal Energy Efficiency Ratio (SEER) is how the HVAC industry measures the efficiency of air conditioners and heat pumps. 

SEER is essentially some very simple math that gets more complicated if you dig in. It’s how much cooling a unit puts out during a typical warm period, divided by the energy needed for that unit to produce that cooling.

But the practical value of a SEER rating is its ability to estimate how much electricity and money is required to cool a home each year.

What SEER rating should I buy?

All things being equal, it’s better to buy a higher SEER-rated cooling system. But things will not be equal. The upfront cost of a unit, the amount of space you’re cooling, the length and temperature of your summers—all these things play into the efficiency decision.

In general you should consider upgrading to a higher SEER if you live in a very hot climate (we’re looking at you, folks in Texas and Florida) and/or if you have a large home.

The best way to see how much a higher SEER unit can save you is by checking online SEER calculator. Be sure to double-check your electricity costs, the tonnage size of your unit, and other factors.

Let’s run through some examples to see if higher SEER units are worth the additional cost.

How much does a higher SEER unit cost?

Higher SEER units generally don’t require more labor to install. And they generally use the same air handler (the inside unit). So by looking at the cost of various condensers (the big box that sits outside your house), we can see how much higher SEER units cost.

Buying a 3-ton, 13 SEER Goodman outdoor A/C unit from direct-to-consumer site eComfort costs $1,354 (at time of publishing). The same unit with a 14 SEER rating is a bit more, at $1,516. The 16 SEER version is $1,681. Then the prices rise substantially: An 18 SEER unit is $2,935, and a 20 SEER unit is $6,140.

Heat pumps from the same manufacturer have a slightly different price curve. A 3-ton, 14 SEER unit costs $2,034, 16 SEER is $3,112, 18 is $3,679, and 20 tops out at $7,069.

It’s worth noting that the 13/14 SEER A/C and heat pump units are single-stage, while the middle and higher-end units are almost all dual-stage or variable speed. So in addition to getting a unit that is more efficient, you’re also getting something that makes your home more comfortable.

In addition to that, heat pumps also provide more efficient heating in the winter. That’s why if you’re thinking about investing in a more efficient AC unit, we recommend installing a heat pump. As we covered in this article, the total savings can add up to $10,000 over 15 years, which puts the numbers above to shame.

How much will a higher SEER unit save?

Using the calculator linked above, If I live in Baltimore, Maryland, ran my A/C or heat pump for about 1,100 hours a year, and bought a 3-ton, 20 SEER air conditioner or heat pump instead of a legal-minimum 13 SEER unit, I’d see 35% savings, or about $143, given the weather and cost of electricity there. That’s $715 in five years, or $1,430 in 10.

But move me to Atlanta, Georgia, where I’m running my A/C or heat pump 1,700 hours a year, in hotter weather? Now I’m saving $212 per year, $1,059 in five years, $2,188 over 10 years. And if I bought a heat pump? I’m saving a lot more on my winter heating too.

Given that a 20 SEER unit cost nearly $5,000 more than a 13 in our online shopping, the jump may not be worth it, unless your home is enormous, your electricity remarkably expensive, or you live in Death Valley.

As we mentioned above, you’re better off getting a low SEER heat pump than a high SEER AC unit.

What about a 16 SEER vs 13 SEER?

Here’s where the math may better line up. The Baltimore homeowner with the 3-ton unit is saving just $85 per year with a 13-to-16 SEER increase. Then again, their 16 SEER unit only cost $327 more than the 13, so they’d handily make that up in less than 5 years, and keep saving beyond that.

In Atlanta, the 3-ton 16 SEER unit is saving $113 a year, paying for itself in less than 3 years.

The difference between SEER and EER

The “S” stands for “seasonal,” and that’s the big difference. EER (Energy efficiency ratio), like its sibling SEER, also measures how much power it takes to produce a certain amount of cooling, but it’s not scaled to the real costs of a typical season.

EER’s baseline model is a unit running when it’s 95 °F (35 °C) outside and 80 °F (27 °C) inside, at about 50% relative humidity inside. The SEER model takes into account a range of temperatures from 65 °F (18 °C) to 104 °F (40 °C).

In other words, SEER tries to account for the fact that temperatures outside change, and with them the efficiency of cooling units do too. EER, by comparison, measures efficiency in a fixed environment. 

What about HSPF?

HSPF stands for Heating Seasonal Performance Factor. It’s a measure of how much electricity it takes to provide a certain amount of heating. In other words, HSPF measures how efficient a heat pump — an air conditioner that can also heat a home — is at providing heat to a building. 

Comparing the HSPF of a heat pump against a traditional furnace is a good way to get a sense of how much a heat pump can save you over traditional fuel-based heating.

Other things to consider

SEER isn’t the only thing to consider when buying a cooling system. As we’ve seen, there is a point of diminishing returns, where buying a slightly higher number doesn’t really pay off. But it’s a helpful starting point when comparing different heat pumps and air conditioners.

Here are some other things to consider and know about SEER ratings.

The minimum SEER rating

The U.S. Department of Energy made this part easy for most of us. If you live in the southeast or southwest, your new system must be at least 14 SEER. In the northern half of the country the minimum SEER is 13. Starting in 2023, each of those numbers goes up by one point.

The SEER range

Most air conditioners and heat pumps in the U.S. have a SEER rating from the current legal minimum of 13 up to around 20-25, depending on the region of the U.S. That’s progress—in 1992, the minimum legal amount was 10. The upcoming minimum of 14 is at least a 20% energy savings for most of the country.

There are some remarkably high-SEER units around, especially in mini-split configuration. Carrier announced a 42 SEER mini-split for a single zone in 2018, and there are higher-SEER units regularly announced and showcased within the industry.

Is a heat pump with a higher SEER also more efficient at heating?

Generally, yes. Because a heat pump essentially works like an air conditioner in reverse to provide heat, a unit that can use less power to compress and expand refrigerants to move heat around in the summer can do the same in winter.

Your heat pump should also have an HSPF rating though, which is a better measure of its heating performance. 

Do ductless mini-splits have higher SEER ratings?

Generally, yes, ductless mini-split systems, whether heat pump or traditional A/C, are more efficient and have higher SEER ratings than traditional “split” systems. This is for two reasons.

One reason is that mini-split systems allow for individual rooms, or zones in a home, to be set to different temperatures, depending on need. A standard forced-air system pushes air to the entire house, doing so whenever a main thermostat tells it. You can somewhat control this with vent shutters, but distributed units will always be more effective.

The other reason is that forced air systems lose efficiency in their ducts. Mini-split systems run refrigerant to and from a main outdoor unit, a more efficient heat transfer system.

Do dual-stage and variable-speed cooling systems get higher SEER ratings?

Yes, dual-stage and variable-speed cooling systems are almost always more efficient than their single-stage counterparts. .

Cooling and heating systems are sized for a home based on the coolest or hottest day of the year. A single-stage system is always drawing the same power to run, whether it’s a slightly warm day or a swampy supernova. Dual-stage and variable-speed systems can work at lower energy levels when needed.

Because they’re running more often, dual-stage and variable-speed systems also do a better job of constantly moving air and keeping a home dehumidified. This in turn keeps temperatures down, and makes people feel cooler.