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How to Calculate HVAC Energy Savings Like the Pros

Calculate HVAC energy savings

Are you considering replacing your older air conditioning and/or heating equipment in the hopes of reducing your energy bills? If your equipment is 10 years old or more, and especially if you have had a number of recent repair issues, it’s smart to look into it. But how much HVAC energy savings could you see, and is it worth investing in new equipment?

In this article, we’ll share a free tool used by HVAC experts that makes it easy to crunch the numbers. Plus we’ll explain the terms and ratings used to compare new energy-efficient air conditioning and heating equipment.

HVAC energy savings: how much savings will you get with new equipment?

If your HVAC equipment is nearing the end of its life span (typically 10 years for residential systems, and closer to 15 years for commercial systems), and it’s been unreliable or under-performing, chances are your energy bills are spiking. That’s because older equipment loses efficiency over time. It runs longer to reach set temperature, which uses more energy.

When you invest in more energy-efficient equipment, your energy usage will go down. The question is, will your HVAC energy savings add up to enough to justify the up-front expense of new equipment? 

To answer that question, you need some reasonable estimates of how much energy savings you could get by replacing equipment. And of course, the equipment you choose impacts how much you can save. 

So let’s start with a quick primer on the energy efficiency terms and ratings used to compare the efficiency of new HVAC equipment.

Terms for comparing HVAC energy efficiency

SEER measures energy efficiency for air conditioners

SEER stands for Seasonal Energy Efficiency Rating. SEER measures the energy efficiency of cooling equipment, calculated based on a seasonal average. Every new unit has been assigned a SEER rating, and you can compare ratings between the different units you are considering. A higher SEER rating means the unit has better energy efficiency and lower electricity usage. 

According to U.S. Department of Energy regulations, all new air conditioning systems installed in our area (New York) must have a minimum rating of 13. Today’s most efficient central air conditioning systems have SEER ratings between 20 and 28. Heat pumps and ductless mini-split systems can have ratings of 30 or higher. Chances are, your older unit’s SEER rating is less than 10.

AFUE measures energy efficiency for heating systems

AFUE stands for Annual Fuel Utilization Efficiency. AFUE measures the energy efficiency of heating equipment, specifically furnaces powered by natural gas, oil, or propane. Like SEER ratings for AC units, new heating systems have AFUE ratings to help you compare the energy efficiency. Higher AFUE ratings mean better energy efficiency and lower fuel usage.

The U.S. Department of Energy regulations set the minimum AFUE at 90 percent efficiency for new systems installed in the northern part of the country. Many new high efficiency gas furnaces have ratings as high as 98 percent.

A helpful tool for calculating HVAC energy savings 

So how can you figure out how much energy you stand to save by upgrading to more efficient equipment? An online calculator from ServiceTitan, a company that provides tools to the HVAC industry, makes it simple to get a good estimate.

How to calculate HVAC energy savings for new AC systems 

To calculate HVAC energy efficiency for a new air conditioner, you’ll need the following information:

Capacity of your existing air conditioner. This is measured in BTUs (British Thermal Units), representing the amount of heat the unit can remove from the air in an hour. Professionals also refer to a unit’s capacity as “size” but it has nothing to do with how big the unit is. You can find it on the unit’s manufacturer label, near the model and serial number.

Cost of Electricity (KWH). To get an accurate estimate, find out the rate you are paying for electricity per kilowatt hour. You can find this on your electricity bill.

SEER rating of your existing unit’s SEER rating. Look for a yellow “Energy Guide” sticker on your unit, which shows its SEER rating. 

SEER ratings of new systems you are considering. You can find these in sales quotes, on product tags, and on product website pages.

With this information, it’s quick and easy to calculate HVAC energy savings. In the calculator tool, select COOLING at the top. Enter your state, your electricity rate, the SEER of your old unit, and the SEER of a new unit you’re considering. Then hit CALCULATE. 

The chart on the right shows you how much money you will save over 5 years, 10 years, and 15 years with a new system that has the specified SEER rating.

You can also easily do a similar calculation for a new heating system by selecting the HEATING option of the top of the tool.

How to make sure you get the energy savings you expect

It’s important to realize that the calculated HVAC energy savings represent optimal values for a system that’s correctly sized, properly installed, and regularly maintained.

So make sure you work with a trusted professional to select and install your new equipment, and don’t neglect regular maintenance to keep your system in good condition.

Learn more about the best options for new commercial replacement AC systems with Arista’s helpful guide: The Ultimate Guide to NYC Light Commercial Air Conditioning.

If you’re in the NYC area, contact Arista for a maintenance agreement estimate.