I’ve been learning about heat pumps and how they work, and I stumbled upon the SEER rating as one of the key numbers to look at.
I thought I’d write this article to explain what the Seer rating is and exactly how to figure it out. So, how do you determine the SEER rating of your heat pump?
There are two methods, 1) using a manual calculation and 2) finding the rating provided by the heat pump manufacturer. To find the manufacturer’s SEER rating, you can locate it on your heat pump, and you can also find it on the manufacturer’s official website.
The exact steps to find it needs further explanation, so I’ll explain exactly how to do it below. And once you’ve found it, you’ll probably be interested in how it compares to other heat pumps and whether it’s any good. So, I’ll include that information in this article for your reference.
How to Manually Calculate Your SEER Rating
Before I get into the exact method, in my opinion locating the special sticker on your heat pump is the fastest way to find it. I explain what it looks like and exactly where to find it in this article.
But, sometimes, the label can be worn off or not be there at all. When that’s the case:
- New heat pumps will sometimes have a document sealed in plastic stuck to the side of the heat pump. This will typically have the SEER rating on it.
- You can find the SEER number on your building permit.
- Some manufacturers will list the SEER rating as part of the model number.
- Doing a quick Google search for the make and model online.
- Giving a call to the manufacturer or sending them an email.
If none of these options are available for your heat pump, you’ll want to do a manual calculation. Here’s exactly how to do that.
Bear in mind that you need to do many numbers and calculations, so it’s a good idea to use a spreadsheet to keep track of all the numbers.
1. Find the British Thermal Unit (BTU) Usage of Your Heat Pump.
The steps to find the BTU of your heat pump is the same as finding the SEER number. Hopefully, you’ll have better luck finding the BTU number.
You can also find the BTU if you know the ton of your heat pump or your heat pump’s kWh.
If you only have the ton of your heat pump, you can get a rough estimate of the BTU using the formula:
1 US ton (907 kg or 0.9 tonnes) = 12,000 BTUs according to Wikipedia.
This table gives some average numbers:
|Ton of your heat pump in US tons||BTUs|
If you have the kWh of your heat pump, you can convert that into BTUs. Using, the known quantity 3.5 kW = 12,000 BTUs. Which I’ll demonstrate below so you can work it out.
An important note here: If you see kiloWatts (kW), or Watts (W), it’s interchangeable with kiloWatt hours (kWh) and Watt hours (Wh). Which is how many kW or W your heat pump uses in an hour. They’re equivalent.
Using some fancy algebra, I found that 1 kW = 3248 BTUs.
You can multiply the number 3248 by the kW your heat pump uses.
For example, to calculate the BTUs of a 3 kW heat pump, you can do:
3 kW * 3248 BTUs
Which is 10,285 or 10,285 BTUs.
Now that you have the BTU your heat pump produces, you can move on to the next step.
Insider’s Tip: You can also find the heat pump tonnage in the heat pump model number. Look for a number like 18, 24, 30, 36, 42, 48, 54, or 60 divisible by 6. The result is the heat pump tonnage.
2. Calculate the BTU Used Per Hour (BTU/h)
Wikipedia states that 1 Watt per hour (Wh) = 3.412 BTU/h
Since we’ve got the kWh from the last step, you can use that to get the BTU/h.
To convert the Watts per hour to kWh, you can multiply by 1000 since there are 1000 Watts in kiloWatt.
In long-form math, we multiply both sides by 1000, but you can think of multiplying the whole formula by 1000.
1 Wh * 1000 = 3.412 * 1000
1kWh = 3412 BTU/h
To calculate it for a heat pump with a different kWh, you need to multiply both sides of the equation by whatever will turn 1W into your kWh.
For example, if it’s 2.5 kWh, you need to multiply 1 W by 2,500 to turn it into 2.5 kWh.
1 Wh * 2,500 = 3.412 * 2,500
2.5 kWh = 8,530 BTU/h
3. Finally, Calculate the SEER Rating
Yay, finally at the final step. In this step, you divide the BTU/h by the Wh to get the SEER rating.
According to this scientific paper, the SEER rating is calculated by dividing the BTU/h by the Wh of your heat pump. So, you first need to find the Wh of your heat pump.
Using the example above, I get:
8,530 BTU/h / 2500 Wh = a SEER rating of 3.4
You can substitute in your numbers to find the SEER rating.
What is the Minimum SEER Rating for Heat Pumps?
In the USA, the minimum is a SEER rating; a heat pump sold needs to be 13+ in the north half of the country, and a SEER rating of 14+ in the rest of the country, according to the US Energy Information Administration.
It’s said that in 2019, the US Department of Energy proposed that the minimum SEER rating is set to rise by 1 for both regions in 2023.
This would mean the minimum SEER rating for heat pumps sold in the north of the country will be 14 in 2023 and 15 in the rest of the country.
The South, as defined by the US Energy Information Administration, which has a SEER rating minimum of 14 currently, includes the states of:
- New Mexico
- South Carolina
- North Carolina
And all other States have a minimum SEER rating of 13. It looks like it’s to reduce the cost of air conditioning since most of the States in the South has hot summers and mild winters.
Does a Higher SEER Cool Better?
The formula for a SEER rating is calculated as the amount of cooling divided by the amount of energy it uses. So, a higher SEER heat pump or air conditioner won’t cool your home faster. It will only be more energy efficient.
If an air conditioner cools the air using less power, it will have a higher SEER rating.
A higher SEER rating will save on electricity costs, but the cost may not offset the fact that a higher SEER rating heat pump is more expensive. So, it does depend on the difference in price between the different units you’re looking at.
How Do I Know What SEER Rating I Need?
There is a minimum SEER rating that manufacturers can sell. It’s 13 in the northern states and 14 in the southern states. Other than that, a heat pump with a higher SEER rating will give you more heating and cooling for the same amount of power, and your electricity cost will be less.
So, you want to get the highest SEER rating you can. Additionally, each home is a different size, and you will need to figure out what size heat pump will be best for your home/office.
As a first step, according to Unique Heating Solutions, you can work it out roughly based on the size of your home.
For every 550 square feet (51 square meters) of heating or cooling, you need a 1-ton capacity.
For example, if you have a 1000 square foot (100 sq meter) apartment, you’ll need a 2-ton heat pump.
On top of that, there is a range of other factors that go into figuring out what heat pump size you need, such as:
- What the building’s made of (brick/wood)
- The amount of insulation it has
- The amount of sun the house gets
- Whether it has double glazed windows
- If there are spaces where air can circulate easily, such as large spaces under the doors
This can all be factored in using a calculation known as a Manual J. Here’s an excellent video that shows how it’s calculated:
Most folks aren’t engineering majors or HVAC experts, so it’s often easier to have a consultant do this all for you rather than work it all out yourself, which can take many hours, especially for someone who’s never done it before.
Is 14 SEER a Good Rating?
According to Trane, a leading heat pump manufacturer, most heat pumps have a SEER rating between 13 and 21. So, it’s technically on the low end, and more energy efficiency is available. But, the higher SEER heat pumps also can be much more expensive than a 14 SEER.
14 is also the minimum SEER rating in the South of the USA, and 13 in the country’s rest. And both minimum’s are going up to 14 and 15 respectively in 2023.
So, it can be a good idea to get ahead of the curve to be eligible for tax credits – more on this later in the article.
Also, that way you won’t have to buy another one in a few years.
How Much More Efficient is a 20 SEER vs. 14 SEER?
Based on the recent research in Complete Guide to Heat Pump SEER Ratings, a 20 SEER heat pump is roughly 30% more efficient than a 14 SEER heat pump. However, it will vary from model to model, translating to a 30% saving in electricity costs.
A 20 SEER heat pump is typically much more expensive than a 14 SEER heat pump, so to get the full picture, you’ll want to look at the electricity cost savings and compare it to the difference in price between the two units.
For example, cost savings between the different units, check out the same article I linked at Complete Guide to Heat Pump SEER Ratings.
Should I Get a 14 SEER or 16 SEER?
A higher SEER rating is more energy-efficient, so you’ll use less electricity to get a 16 SEER. If you use less electricity, you’ll have a lower electricity bill at the end of the day, and you’ll spend less to get the same amount of heating and cooling.
However, 16 SEER heat pumps are more expensive than 14 SEER heat pumps. Based on some analysis I did in this previous article. The cost savings are around $100 a year. If a SEER 16 heat pump is $1000 more expensive, it will take ten years to offset the cost.
Therefore, it depends on the prices of the different models you’re looking at. I recommend bookmarking that article as a reference when you’re choosing between two other heat pumps of varying SEER ratings.
What HVAC System Qualifies for Tax Credits in 2021?
According to Energystar.gov you can get a $300 federal tax credit for split heat pump systems with an HSPF >= 8.5, an EER >= 12.5, and a SEER => 15. You can get a tax credit of $300 for packages systems for those that have an HSPF >= 8, an EER >= 12, and a SEER => 14.
For AC units, the requirements are different. For split systems, you need a SEER rating >= 16 and an EER >= 12. Package systems need to have a SEER >= 14 and an EER >= 12.
The numbers above expire on December 31st, 2021. For all the details provided on the official US government website, click here.
You can also use it to double-check the latest requirements after the expiry date.
There are many state tax credits you may be eligible for. You can take a look at the options by the state on this website. Many of them have their requirements, so it can save you some time to speak with an accountant who specializes in this area.
To figure out your heat pumps SEER rating, you can use formulas that involve knowing some critical numbers about your heat pump, such as the BTU and kW usage of your heat pump.
The higher the SEER rating, the more energy-efficient it is.
The easiest first step is to find the sticker or label on your heat pump. But, if it doesn’t have one, you can also look online for the make and model to find it.
Failing that, I would do a manual calculation.
There are tax credits for energy-efficient heat pumps at the federal level, and there are also state tax credits for each state.