AC Unit Types, Sizes, And Their Energy Efficiencies

Home AC systems come in three primary varieties: conventional split-setup AC units, ductless systems, and packaged air conditioners. All three types share the same basic functionality to dehumidify air and lower temperature in our homes. These ACs need a condenser coil, evaporator coil, a refrigerant and compressor to basically pull humidity and heat out of the house while providing cool air to your personal spaces.

Irrespective of the system type that’s ideal for your house, sizing it right will offer the ideal results in performance, energy efficiency, and comfort. For most individuals, determining the right size would be best-taken care of by an expert HVAC contractor. Professional HVAC contractors would have expert knowledge and understanding of the various nuances in the system and can carry out cooling load computations required for correct AC system sizing.

However, comprehending the principles behind sizing the cooling system and its significance would help when contemplating a new setup for your house. For instance, as far as your home, AC’s size is concerned, bigger isn’t always better. Equipping your house with a bigger system with multiple cooling capacity tons not only utilizes more energy than required but the bigger size AC may even cycle off and on a bit too frequently without ridding the air of the humidity adequately enough, leaving behind a cool but damp feeling in the air.

On the other hand, an AC that is a bit too small for your household would have to work beyond its capabilities to cool your space, thereby consuming increased energy and still not doing its job correctly. An AC size that matches your space would offer optimal cooling and also not give you nightmares in the form of spiked up energy bills. Since there is no best or standard AC size and because the right size is imperative for proper energy consumption and solid comfort, it’s always recommended you get your property professionally assessed. Your local HVAC contractor will invariably account all the aspects involved and ascertain the correct AC size for your space.

How Do Air Conditioners Get Their Ratings?

Air conditioners are usually rated based on two major factors: energy efficiency and cooling capacity. When you want to know the correct AC size for your house, you should learn more about the AC’s cooling potential measured in tons or BTUh (British thermal units per hour). To compare different units’ energy efficiencies, you would typically check the SEER (Seasonal Energy Efficiency Ratio) numbers, which could be equated to your car’s miles per gallon (MPG) figures.

Cooling Capacity

An AC’s cooling capacity provides a solid measure to help ascertain whether a specific AC unit is the right fit for your home. The cooling capacity of an AC is expressed in tons (or tonnage) or BTUh. Both help you measure the cooling ability of your air conditioner over an hour’s period. A ton of cooling capacity can be equated to 12,000 BTUh. Residential ACs usually fall in the 1-5 to 5-ton or 18,000 to 60,000 BTU range. Anything with bigger cooling capacity will be termed as a ‘light commercial’ system.

Tonnage ratings are usually stated in 0.5-ton increments. In other words, residential ACs are typically rated as 1, 1.5, 2, 2.5, 3, 3.5, etc. Kindly note that there is a significant difference between BTUh and BTU (British Thermal Units). BTU basically measures the total heat required to raise a pound of water by a degree Fahrenheit. BTUh denotes a measure of the amount of heat in BTUs an AC could remove from your house over an hour’s period.

SEER Rating

Air conditioners employ SEER ratings to denote their energy efficiency. SEER numbers are used to help buyers make well-informed decisions about the AC systems they select for their houses. SEER ratings, by definition, represent the entire expanse of cooling offered during the complete cooling season. Similar to a car’s MPG, a higher SEER rating attached to an AC system means increased energy efficiency.

Speaking of which, two AC units having identical cooling capacity may not have the same SEER ratings. For instance, when you see two different three-ton AC models, one could have a 13 SEER rating, and the other one could be a lot more efficient 18 SEER units. Units with higher efficiency numbers could receive a special ENERGY STAR certification. Energy Star is basically an energy program department that recognizes consumer goods for their ability to save energy. If an air conditioning unit is certified by Energy Star, its SEER rating would be higher, and it will use 8 percent less energy at least compared to conventional models.

Estimate the Correct AC Unit Size for Your Space

While you could use formulas to estimate the correct AC unit size for your house, the most accurate and easiest method is to work on it with an HVAC dealer. These dealers would measure your space precisely, weigh in all the factors needed to make the equation, and offer a correct assessment of the proper AC equipment size for your house.

AC Unit Size Computation

To ascertain the correct for your home’s HVAC system, your local dealer would perform ‘load calculation.’ This should help determine the cooling capacity amount needed to maintain the right temperature within your house. Your dealer would compile data, such as square footage, door and window area, climate, and insulation quality to find out the amount of cooling and heating capacity your system requires.

Additional Variables

There are multiple variables that should be considered when choosing air conditioning. Factors your HVAC dealer would usually take into consideration are:

• Total interior space square footage requiring cooling
• Approximate quantity of direct hot sun exposure
• Number of people living in the house
• Numbers and types of equipment or appliances that create heat
• Climate or weather conditions
• Total number and quality of exterior windows
• R-value and quality of insulation
• Construction types, such as vinyl siding or brick exterior
• Airflow assessment/interior ductwork
• Features contributing to cooling and heating gain or loss, such as skylights or fireplaces