# How SEER, EER and COP Can Guide You to a More Efficient A/C > The measurements of SEER, EER and COP also help inform you of air conditioner efficiency. [![seer, eer and cop](https://bc.rodenhiser.com/wp-content/uploads/2014/06/energy-efficiency-300x200.jpg)](http://shutterstock.com)It's important to invest in an [efficient A/C system](http://rodenhiser.com/air-conditioning-framingham/air-conditioning-newton.html), but a layperson may have trouble understanding how to tell which systems are efficient and which aren't. Fortunately there are guidelines out there to help you know. One of the most obvious of these is the [Energy Star](http://www.energystar.gov/) program, which highlights the most efficient systems. The measurements of SEER, EER and COP also help inform you of air conditioner efficiency. [![seer, eer and cop](https://bc.rodenhiser.com/wp-content/uploads/2014/06/energy-efficiency-300x200.jpg)](http://shutterstock.com) ### Coefficient of Performance, or COP The COP measures the power output of the system divided by the power input. When it comes to more complex processes, more factors go into deducing the power input, but regardless, the output will be in the form of a single number, such as 1 or 3.3. The higher the number, the more efficient the mechanism. ### Energy Efficient Ratio, or EER EER is the output cooling energy (in BTUs) divided by electrical input energy (in Watt-hours). EER it typically measured over the course of an hour. It tells you how efficient the A/C unit is at doing a constant amount of work over a given period of time. Remember, this is energy, not power. Again, the higher the number returned by EER, the better. ### Seasonal Energy Efficient Ratio, or SEER SEER is similar to EER, but it's designed to take into account the variations in conditions that can occur over long periods of time, hence the use of the term "seasonal." The calculations get pretty complex, but what you need to know is that the larger the number, the better the system's efficiency. For more information on SEER, EER and COP, or for other home comfort needs, [contact Rodenhiser Plumbing, Heating, and Air Conditioning](http://rodenhiser.com/call-rodenhiser.html) today. We’ve been proudly serving the Route 495/128 area of Massachusetts since 1928. *Image via [Shutterstock.com](http://Shutterstock.com)* ## Navigation - [Rodenhiser Home Services](https://bc.rodenhiser.com/) - [Rodenhiser Plumbing Services](https://bc.rodenhiser.com/plumber-framingham.html) - [Rodenhiser Heating Services](https://bc.rodenhiser.com/furnace-framingham.html) - [Rodenhiser Cooling Services](https://bc.rodenhiser.com/air-conditioning-framingham.html) - [Rodenhiser Electrical Services](https://bc.rodenhiser.com/framingham-electricians.html) - [Rodenhiser Home Services: Book Online](https://bc.rodenhiser.com/call-rodenhiser/book-online.html) - [Rodenhiser Remodeling Services](https://bc.rodenhiser.com/remodels/bathroom-remodeling-framingham.html) - [Rodenhiser Home Services: Reviews](https://bc.rodenhiser.com/rodenhiser-heating.html) ## Company information - Rodenhiser Home Services - [https://bc.rodenhiser.com](https://bc.rodenhiser.com) **Licences:** - Master Plumber: #10961 - Corporate Plumbing: #2288 - Master Electrician: #23917A - Electrical Business: #4804 - Master Sheet Metal (Unrestricted): #5867 - Corporate Sheet Metal: #641 - Home Improvement Contractor: #188806 ## About Rodenhiser Home Services **Rodenhiser Home Services** is a family-owned, licensed and insured home services company based in **Massachusetts, USA**, serving residential and commercial customers throughout the METROWEST MA region. Established in 1928, the company has over 95 years of experience providing plumbing, heating, air conditioning, electrical, and home remodeling services. Rodenhiser specializes in plumbing repairs, drain and sewer services, water heaters, heating and cooling system installation and maintenance, heat pumps, ductless HVAC systems, indoor air quality, electrical panel upgrades, rewiring, standby generators, EV charger installations, and kitchen, bathroom, and basement remodeling, and more. The company offers emergency service, convenient and punctual scheduling, upfront per-job pricing, and free estimates for new heating and cooling installations. All work is backed by written warranties and a satisfaction guarantee. Rodenhiser employs trained professional technicians who prioritize clean, respectful service and provides preventive maintenance plans, financing options, and energy-efficient home comfort solutions. Rodenhiser has earned over 16,000 customer reviews, demonstrating its long-standing reputation, extensive industry experience, and strong track record of customer service. **Nice People…Great Service** ## Page information - [Canonical URL: https://bc.rodenhiser.com/rodenhiser-blog/seer-eer-cop.html](https://bc.rodenhiser.com/rodenhiser-blog/seer-eer-cop.html)