Central air conditioners cool a home by circulating cool air through a series of ducts. High efficiency air conditioners require less energy to cool a home, resulting in savings in energy and utility bills.
Like a heat pump, a central air conditioner uses electricity to transfer heat. A central air conditioning system will provide the most even, comfortable cooling throughout a home. And installing a high efficiency central air conditioner can save a homeowner 20-50 percent in comparison with an older system.
How efficiency is measured
SEER is determined by taking the total cooling energy needed for a cooling season and dividing it by the total electrical energy used by the air conditioner during the cooling season. A higher SEER indicates higher efficiency.
EER is an older method of calculating efficiency. Like SEER, the EER of a cooling unit is determined by the total cooling energy output divided by the total electrical output. EER ratings are most often used with room air conditioners, but there are EER requirements for high efficiency central air conditioners.
The difference between the two is that EER measures efficiency at one constant temperature, while SEER calculates efficiency at varying temperatures. The difference can be seen by the S, which stands for Seasonal, in SEER.
High efficiency central air conditioners have efficiency ratings of 15 SEER or greater and 12.5 EER or greater for split systems, and 15 SEER or greater and 12 EER or greater for package units. High efficiency central air conditioners have the Energy Star label.
As of July 16, 2016, all central air conditioners sold in the United States had to meet minimum efficiency levels of 14 SEER. In the states of California, New Mexico, Nevada and Arizona standards also included minimum EER values (energy demand on a very hot day). The minimum efficiency levels in these states are 14 SEER and 12.2 EER.
On January 1, 2022, new standards will be implemented which raise the minimum central air conditioner efficiency levels to 15 SEER. The new efficiency levels in California, New Mexico, Nevada and Arizona will be 15 SEER and 12.5 EER.
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Types of Central Air Conditioners
Central air conditioners are either split-system or packaged units.
Most central air conditioners are split-system. These systems have an outside unit next to the house and a furnace or air handler inside. In these systems, ductwork is connected to the inside units. If a furnace is already installed in the house, this is the least expensive central air conditioner to install.
Packaged systems have the coils and fan contained in one outdoor cabinet, located either on the ground on a cement slab or on the roof of the building. Ductwork connects to a packaged system by passing through a wall or roof. Packaged air conditioners often have electric heating coils and can be used as an alternative to having a furnace indoors.
Benefits and drawbacks of a high efficiency central air conditioner
The main benefit of a high efficiency central air conditioner is that the higher efficiency can save money on electric bills because it will need to run less. A high efficiency unit is much more efficient than a model manufactured only 10 years ago, often by 20 to 50 percent, and it is estimated that high efficiency central air conditioners are about 15 percent more efficient than today’s standard models. They also deliver more comfortable and consistent temperatures, are better for the environment than older or less efficient models, and tend to run at much lower operating sound levels.
Another benefit is a federal tax credit of 10% up to $500 or a specific amount from $50 to $300 on Energy Star labeled, high efficiency central air conditioners. This tax credit expires on December 31, 2016.
The main drawback of high efficiency central air conditioners is that the purchase price can sometimes be higher than that of mid-efficiency units. Much of the upfront cost, though, depends on factors such as the size of the unit and whether it is a split or packaged unit. Also, cost can vary by the brand and model of air conditioner.
eAnother drawback that deserves serious consideration is that, with a split-system high efficiency air conditioner, the furnace may need to be replaced at the same time as the outside air conditioning unit. This is because the blower motor, which blows the cool air through the ductwork, is located inside the furnace. If a new high efficiency air conditioner is connected to an older furnace, it will not perform to its rated capacity. It is recommended that if a furnace is over 15 years old, it should be replaced when the new central air conditioner is installed.
Should you buy a high efficiency central air conditioner?
The decision of whether or not to purchase a high efficiency central air conditioner will vary from one homeowner to the next. Today’s high efficiency central air conditioners can save homeowners substantial amounts on energy while being eco-friendly. For many people, the higher efficiency is worth it. For those with an older furnace that will also need to be replaced along with the old air conditioner, the price may prove too high.