What SEER Rating Do I Need for My HVAC System? Factors for Good SEER Rating

We all want to keep our homes comfortable through air conditioning while keeping our electricity bills low. 

To do that, we need heating, ventilation, and air conditioning systems with the best energy efficiency. A good measure of an HVAC system’s energy efficiency is the SEER, an acronym for Seasonal Energy Efficiency Ratio. 

But, what SEER rating do I need? Read along to find out a detailed interpretation of SEER and what value will be best for your home. 

What SEER Rating Do I Need for my HVAC System

You need a SEER rating that will allow you to spend the least possible amount on your cooling and heating bills and qualify for a tax credit and manufacturer’s rebates. Ideally, this is any value between 14 and 17 SEER. 

Based on US Department of Energy guidelines, any SEER value over 13 is excellent. In light of these guidelines, today’s most efficient AC models have a SEER of between 15 and 17.  

You have probably heard that the greater the SEER value, the better. This is true, but the highest SEER value may not be the best for you. 

Why the Highest SEER rating may not always be the Best

While some new central AC systems have SEER values as high as 26, anything with a SEER value above 20 will often be much more expensive to purchase. 

The whole idea of buying a more energy-efficient unit is to save money on your energy bills.

Considering how electricity prices have risen in recent years, homeowners have become more conscious about ways to cut their energy consumption.

And, because the SEER rating provides a way to make an intelligent choice regarding AC power consumption, you want to choose an option that helps you maximize your savings. 

The problem is that high SEER units can cost a lot more than a base model. For example, you can spend about $2,500 to $4,000 more on a high SEER air conditioning system.  

If you add the cost of installation and ductwork, you could be looking at a figure north of $13,000. Now, a more efficient unit will cost less to provide cooling in the long run indeed.

But a typical air conditioning system lasts about 15 to 20 years, which means the estimated $4,000 price difference is pretty much on the higher side.   

It would be a tough call to expend more money upfront with the hope of saving more in the long run. The colossal upfront figure is likely to cancel out the long-term cost-benefit. 

So, it may be wiser to save money upfront by purchasing an AC unit with a lower SEER rating as long as it carries the Energy Star label.

The label indicates that the product has passed the federal government’s energy efficiency specifications and requirements. With that, you can qualify for as much as $1000 in tax credits and rebates.

Notice that rebates can be time-bound. So you need to submit all the required information for the rebate as soon as possible, usually within 30 days of purchasing your new HVAC system.

With a little more legwork, you could even take advantage of multiple incentives simultaneously – multiplying your savings on the same purchase.  

The best way to take advantage of these incentives is to work with a certified HVAC contractor. 

The HVAC specialist will be qualified to help you determine the most appropriate SEER rating for your prospective new AC system. 

What they do is use particular equations to average the maximum EER (Energy Efficiency Raito) over the range of expected seasonal temperatures in your area.

In addition, they can advise you better on the rebates associated with the AC unit you want to buy. These rebates are often specific to a brand, air conditioner system type, or efficiency levels.

With such information, you can go shopping knowing all the tax credits and rebates that can bring down the overall cost of your high SEER system.  

Other Factors that Determine the Best SEER Rating 

Determining the best SEER rating cannot happen in isolation. Several factors directly affect how efficiently an air conditioning system will run.

When determining the best SEER for your new appliance, you will want to consider all these factors. A SEER rating indicates the maximum potential of a unit when every other factor is at its optimum – over a given season. 

Therefore, an air conditioning unit with a 22 SEER, for instance, will not always perform at 22 SEER due to the limitations of the laws of thermodynamics. 

ACs energy efficiency and performance will constantly be subject to outdoor temperatures, sun exposure, thermostat settings, mechanical issues, and building envelope.

To better understand these dynamics around the Seasonal Energy Efficiency Ratio (SEER), some people liken it to a vehicle’s gas mileage.

The fuel economy you realize on bumper-to-bumper traffic with intermittent acceleration will not be the same as freeway driving.

If the conditions are unideal, your 22 SEER unit could, for example, perform at as low as 16 SEER. By interpretation, you will have spent the premium upfront cost only not to realize your projected long-term savings.  

When doing your AC installation, it is, therefore, crucial that you take into account the following factors to ensure the appliance will live up to its SEER rating. 

Proper ductwork

any duct leakages can lead to significant losses in energy. Leaks in the supply duct, in particular, can result in a direct loss in the air conditioner’s total capacity. 

And, return duct leaks can cause unfiltered, unconditioned air to enter the house from the crawl space or attic. 

Overall, leaky ducts can lead to losses of as much as 30% of cooled air. In addition, when this air seeps into the attic or basement instead of the living areas, a lot of wastage diminishes the AC’s overall energy efficiency.  

Proper airflow

The size of air ducts or how they are matched with other equipment can affect the airflow.

Any mismatch or too small air ducts can inhibit the flow, leading to reduced efficiency in achieving the desired change of temperature across the evaporator unit. 

The other factors that can inhibit airflow include a damaged fan motor or a poorly designed layout.

If you are installing a new unit, a thorough system audit can help reveal these issues so that you may address them before putting the new installation in place. 


 Your air conditioner needs a specific level of refrigerant to perform optimally. Overcharging or undercharging can affect the unit’s ability to perform up to its SEER rating.

Size of the air conditioner in reference to the size of your home

 A mismatch of these two can be disastrous. An AC that is too small would never stop running. It will be struggling to heat the relatively oversized home and burning up energy in the process.

An oversized unit is no better either. Its sheer size will lead to diminished functionality and poor energy use. 

Consuming more energy than desired would mean that the appliance is not as energy efficient as the SEER rating. 

Thankfully, it is easy to avoid this kind of scenario. Take the time to hire a qualified HVAC technician who will be sure to match up the AC unit size with the exact size of your home.

Working with an established contractor will also mean that you have protection against any issues arising from your installation.

For instance, if there is a problem with the installation, you can schedule an amendment to the system at no extra charges.

The level of insulation in your home

insulation determines how much energy is lost into the outside environment. If you have an under-insulated window or attic, you can expect more heat outside to get into your house.

The air conditioner will have more work cooling your home and keeping it that way. The hotter the summer heat, the more the cooling unit will struggle.

This way, it will have difficulty keeping its energy efficiency where it was designed to stay. You need to look into adequate insulation so that your AC unit can run at the standard rate and save energy. 

Some of the home insulation measures you could consider are:

  1. Sealing off any air gaps with foam sealant
  2. Installing triple-pane windows
  3. Using roofing materials such as reflective shingles that contribute to lower energy inside the house

Bonus Tips to Keep Your AC Unit Running at Peak SEER 

A lot goes into determining the best SEER for your home and keeping your AC running at its peak. So here are some two things to simplify your task. 

  1. Work with a reputable installer. The best way to ensure your cooling or heating unit will work at its peak SEER is to do it right from the get-go. Go for HVAC contractors with the best customer feedback. The feedback will indicate a track record of excellence, from which you can know what to expect. Here’s a guide for hiring professional HVAC technicians.
  2. Give your HVAC system the care and maintenance it requires. Proper maintenance means getting a reliable professional to check and tune up your cooling, heating, and ventilation system every few years to prevent any mechanical failure.

As you can see, indeed, there is a lot that goes into determining the SEER rating you need. But, if you are reading this, you are in luck. Now you have the tips in this guide to help you know how to approach the decision. 

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Jesse Pinkman is a passionate HVAC professional writer who grew up repairing any home appliance on which he could lay his hands. He is responsible for ensuring that every article we publish is SPOT ON. When he's not in the office, he enjoys hiking, watching football, and spending time with his family.