Did you know that the average lifespan of an heating, ventilation and air conditioning (HVAC) system is 15-20 years? Many systems can (and often do) last much longer, especially with proper maintenance, but in the U.S. many homeowners choose to replace or upgrade their systems more frequently. If your system is older than 20 years, you may want to consider replacement, even if it is still in good working order.

Why replace a functioning HVAC system?

In the long term, replacing your air conditioner after only 10-15 years can actually be more economical. This is due to improved efficiency and lowered maintenance costs on newer models.

Newer models also have the added benefit of new features (such as smart home technology or integrated weather monitoring.)

Many utility companies as well as local, state and federal governments offer rebate programs for new energy efficient systems which also helps bring the initial costs down.

So how do you know if and when it would be a good time to replace your HVAC system?  

Well, to answer that question you first need to determine exactly how much your current system is costing you versus what it would cost to install an
d run a new system.   Here are some factors you want to consider when looking at a replacement system.

1. The SEER rating (efficiency)

Every system has a Seasonable Energy Efficiency Rating (or SEER) which is a standard measure of how much cooling a system can provide per each unit of energy.   It is comparable to a miles per gallon rating on automobiles.

The higher your system’s SEER rating, the more efficient it is and the less you will spend on energy costs to cool your home.   Federal standards require that all systems meet a 13 SEER rating standard, and some states (such as California) have even higher requirements.

2. How they work (Single Stage vs. Two Stage)

There are two main types of air conditioner compressors available for residential homes.  They function in two distinct ways and therefore have unique benefits and drawbacks.

Single-stage air conditioner compressors operate on one speed all the time.  They are either ON or OFF, there is no middle ground.  These units tend to have short and frequent on and off cycles in order to maintain a fixed temperature.  They also tend to be the least efficient and most expensive to operate but they are the least expensive to purchase and install.

Variable-speed compressors change their speed based on how much cooling is required.  They mainly operate at low speed to keep the temperatures stable for long periods of time, and only use higher speeds when outdoor temperatures get really high or if a burst of cooling is required.  These are the most efficient systems on the market and have the lowest operating costs.

Two-stage air conditioner compressors are the middle ground between the previous types.  They use HIGH, LOW and OFF settings to maintain your home’s temperatures and reduce the need for constantly cycling on an offer.  As for cost and efficiency, they fall in the middle between single stage and variable speed units.

3. Size, location and lifestyle 

How many square feet you need to cool, where your home is located (desert vs. mountains) and what your typical comfort level is (do you like your home really cool or do you avoid using the AC unless you are really uncomfortable?) are all huge factors when choosing an HVAC system. An HVAC system size is measured by in tonnage.  How many tons your unit is, is comparable to the size engine in an automobile.  A two-ton unit would be like a V8 engine while a one-ton unit would be smaller and less powerful (like a V6).  Any unit over 5 tons is considered a commercial system.

The tonnage of your AC unit does impact the efficiency but this impact is factored into its SEER rating when you want to calculate operating costs.  Bigger isn’t necessarily better, especially if your target is efficiency and costs savings, so making sure you have the CORRECT size of air conditioner is crucial.  A unit that is too small is just as inefficient since it will have to run almost constantly to keep up with demand.

So how do you compare these factors quickly and easily?  Luckily there is an app that does exactly that.

If you are homeowner considering replacing your HVAC system, the Emerson e-Saver app can help you compare the costs and calculate your annual savings based on the type of system,  SEER rating and energy costs in your local area.  You can compare this information against your current model as well as industry standards.


If you are a contractor this Is the perfect app to show find the perfect system for your customers. Being able to immediately calculate the annual costs to own and operate a unit can demonstrate if certain features are worth the initial up front costs.

If you haven't considered the operating costs of your current HVAC system or compared them to newer more efficient models currently on the market, it may be a good time to do so.  An up front investment in a new HVAC system may end up paying for itself long term, but make sure you do the research and know exactly what to look for when investing in a new systems.


Thank you to Emerson for providing the information for this post. Interested in learning more? Check out other heating and cooling tips here.