When it’s hot and humid outside, it can be sticky and uncomfortable inside your South Houston home, especially when your old A/C is having a difficult time keeping up with heat gain. If you’re shopping for a new A/C, pay close attention to A/C efficiency ratings so you are sure to select the right system.
Making Sense of EER and SEER
With all the talk about A/C efficiency ratings, you may be wondering what all those numbers and acronyms mean. A/C systems are rated for efficiency using two methods.
- Energy efficiency ratio (EER) – The EER rating is a ratio of cooling output to energy input (electricity). EER is a steady-state test performed with controlled outdoor and indoor temperatures and humidity for a set period of time.
- Seasonal energy efficiency ratio (SEER) – The SEER rating, like EER, is a ratio of cooling output to energy input (electricity). However, SEER isn’t a steady-state test, as the seasonal indicates. Systems are tested for a simulated season with temperature, humidity and usage changes. Seasonal was added to the EER test because some A/C systems reach peak performance faster than others, giving them an advantage in a timed and limited test. SEER testing levels the playing field. Like EER, the higher the efficiency number (e.g. 17 SEER versus 20 SEER), the greater energy efficiency the system offers.
How to Use A/C Efficiency Ratings
A/C efficiency ratings can be used similarly to the MPG ratings of automobiles when comparing models. For instance, if you’re deciding between two different vehicles, and one vehicle gets 25 percent better gas mileage, you’ll have a good idea how much money you are going to save in gasoline, based on your average usage, for the life of the higher-efficiency vehicle.
EER and SEER can help you determine which A/C system is best for your home and budget. Here’s how:
- Lifetime cost – The lifetime cost of a new A/C is the sum of the purchase price, installation expenses, estimated electricity consumption, and the projected maintenance and repairs from day one through the estimated lifetime of the A/C. If you’re undecided about which A/C to choose, ask your HVAC contractor to conduct a lifetime cost analysis of the systems. In this way, you can see the true investment, from day one, of the systems you are considering.
- Long-term gains – High-efficiency A/C systems with better A/C efficiency ratings than a standard or mid-efficiency unit deliver two big advantages to homeowners. High-efficiency systems deliver better performance for cooling and dehumidification, and high-efficiency systems use less energy to operate. Using the figures from the lifetime cost analysis, your HVAC professional can determine the return on investment (ROI) for a higher-efficiency A/C. The ROI is the point at which a higher-efficiency unit recoups its higher purchase price in energy savings. This is an important point, because from here on out, energy savings above and beyond lesser-efficient models is money in your pocket.
- Energy Star – The Energy Star program uses efficiency ratings to qualify A/C systems (and many other products) to bear the blue Energy Star logo. Central A/C systems must receive minimum 14.5 SEER and 12 EER to become Energy Star qualified. A/C systems must also offer advanced features not available on less efficient models of the same category to earn the Star. Moreover, the ROI must be attainable in a reasonable amount of time. If you want an efficient A/C for your South Houston home, start with Energy Star qualified systems.
- Performance features – The analogy between A/C efficiency ratings and vehicle MPG averages stop when it comes to system output and performance. Yes, a well-designed 4-cylinder motor is going to get higher MPG than a high-performance 8-cylinder work truck, but it won’t have the horsepower and performance. With HVAC systems, however, the opposite is true. In order for a compressor and coils of to be more efficient, they must perform better — better cooling and better dehumidification — while using the same or less amount of electricity. That’s a formula you can work with.
Prepare for Installation
Your new A/C is going to work hard in our Houston climate, and its performance and efficiency are only going to be as good as the efficiency of your home, air ducts and advanced features. Ask your HVAC professional to do a thorough check for air leaks in the home shell and air ducts, and ask about devices that drive performance and efficiency.
For more information about A/C efficiency ratings, please contact Valderrama A/C & Refrigeration.
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