High Efficiency Air Conditioning FAQs
Learn how to select a contractor, how air conditioners are sized, and more.
Being aware of certain technical details regarding your home’s central air conditioning system can make all the difference in ensuring you receive the best service and equipment. It also helps ensure you receive the appropriate equipment for your space and your budget, so that you enjoy maximum efficiency.
Airflow and Charge Check (AC Check) trained contractors promote efficient installations. Through AC Check you can maximize the energy savings of your central AC or heat pump equipment, increase system efficiency, have fewer repairs and longer equipment life expectancy, and enjoy a higher level of comfort.
How Do I select the Right Contractor?
System sizing and proper installation of air conditioning equipment are critical to energy efficiency and home comfort. It’s important to hire a qualified contractor who will calculate the right-sized equipment for your home.
The industry standard for that calculation uses Manual J of the Air Conditioning Contractors Association (ACCA), as required by the state building code. Make sure to ask your contractor to perform this calculation.
In addition, Mass Save® also provides Airflow and Charge (AC) Check training for contractors. AC Check is a test procedure to help verify that a new central air conditioner or heat pump installation has been properly adjusted to deliver optimal comfort, efficiency and savings.
How are air conditioners typically sized to meet the cooling needs for my home?
Your comfort while using air conditioning depends both on reducing air temperature and removing humidity. An air conditioner must run for eight to ten minutes before it begins to dehumidify your home. Properly-sized air conditioning systems will run longer, but use less electricity. Just like a car gets better fuel economy traveling a constant 65 MPH on the highway than it does in stop-and-go traffic, AC equipment runs more efficiently when it runs steadily.
What is Meant by “BTU” and “Ton”?
An air conditioner's ability to remove heat is expressed in BTUs (British Thermal Units) per hour, or "tons" of cooling. Each ton equals 12,000 BTUs per hour, and is equal to the energy contained in one ton of ice, a term left over from the days when buildings were cooled with ice. Your air conditioner should be properly sized based on a Manual J load calculation, and the installing contractor must properly set up the system to condition your house, specific to the climate you live in. AC systems need to perform differently in Phoenix, Miami, or Massachusetts, as the local climates have different temperature and humidity removal needs.
How Does Insulation Affect My Cooling Needs?
A poorly-shaded home with little insulation and lots of air leaks will need more cooling capacity (i.e., more tons of cooling) than a well-insulated and well-shaded home with few air leaks. If you intend to upgrade the energy efficiency of your home with the Mass Save programs, be sure to let your AC contractor know your plans so that they can size your equipment accordingly.
What is the difference between EER and SEER?
EER (energy efficiency ratio) is a measure of how efficiently a cooling system will operate when the outdoor temperature is at a specific level (usually 95° degrees Fahrenheit). It is based on a standard test methodology intended to allow consumers to compare the general efficiency of equipment. A higher EER means the system is more efficient. You can calculate kilowatts if you know the EER and the size, in tons. SEER (seasonal energy efficiency ratio) is a measure of efficiency over an entire cooling season, as opposed to a single outdoor temperature. Residential units are almost always rated in SEER. SEER came into use as a more practical measure, since the temperature outside is not always 95° degrees Fahrenheit. The same relationship holds — a higher SEER means the system is more efficient. SEER is an indicator of the total amount of cooling the air conditioner will provide over the entire cooling season, divided by the total number of watt-hours it will consume.
What is the importance of EER?
Your local sponsors, and the country as a whole, are concerned about using energy efficiently. Efficient usage occurs both in the seasonal and peak arenas. Many advocacy partners in the industry recognize SEER alone does not address demand savings. Use of EER as an industry standard is an attempt for continued improvement in demand performance.
Resources for Finding a Contractor
To find a contractor near you, please use our Find a Contractor tool.
Air Conditioning Contractors of America
North American Technician Excellence (NATE)