Selecting an Air Conditioner – The Big Four Choices

When it comes time to replace the air conditioner for your home, it’s easy to become overwhelmed with information about features, efficiency, and cost. We want to provide you, the customer with an easy checklist when it comes to selecting an air conditioner. In the couple of paragraphs below we will define a few terms for you, and tell you why they matter. If you have any questions at all about what you have read, we are happy to discuss in more detail.



According to, a ton is a unit of measurement for determining cooling capacity. Most air conditioners we offer to customers range from 1.5 to 5 tons. To size equipment properly, we use a ratio of one ton of cooling for every seven-hundred square feet of floor space that is located above the grade level of your home. Basements typically have much lower cooling requirements due to the insulation that comes from the earth surrounding them, so we leave that square footage out of our calculations.

  • If you had a ranch style home with 1500 square foot above grade level, you would need approximately 2.14 tons of cooling to adequately control the temperature in your home. Most equipment is offered in half-ton incremements, so we would round up(to a 2.5 ton unit) to ensure that the air conditioner is large enough.


According to, the Seasonal Energy Efficiency Ratio (SEER) is a measure of the cooling efficiency of an air conditioner. The higher the SEER, the better the energy performance, and the more you will save on your energy bills. In 2015, the federal government put into law a requirement for all air conditioners in the northern portion of the country to have a rating of 13 SEER or higher.

  • What does this mean for you? By law, we have to offer air conditioners that are higher than 13 SEER. We recommend choosing the highest efficiency unit possible so you can get the most out of the investment that you are making in your home by replacing your equipment. The higher the SEER, the more of your hard-earned money you will be saving on your monthly energy bills.

Sound Rating (dB)

Air conditioners are also graded on their sound rating. A sound rating is an expected intensity of sound that can be heard while an air conditioner is running a cooling cycle. A sound rating is measured in decibels (dB). According to, sound levels in a library are normally about 40 dB, normal conversations range from about 50 to 60 dB, and an operating motorcycle or garbage truck can be as high as 100 dB.

  • Sound ratings on the air conditioners we offer ranges from 59dB to 76dB. Since many homeowners have air conditioning units outside a bedroom window, we recommend that you select the quietest equipment possible. Do you want your air conditioner to sound more like a library, or more like a garbage truck?

Stages of Cooling

Most manufacturers of equipment will all have a variable-capacity, two-stage, and single-stage air conditioner in their lineup of products. Lennox is no different. The more stages of cooling the air conditioner has, the more consistently the air conditioner will cool your home. Below, we have described the operation of each type of air conditioner:

  • Variable-Capacity - When the thermostat calls for cooling, the furnace will cool at 35% of its cooling capacity, increasing the cooling rate by 1% until the space reaches the required temperature.
  • Two-Stage - When the thermostat calls for cooling, the furnace will burn at 65% of the cooling capacity for approximately twelve minutes. If the space does not reach the required temperature, the air conditioner will move to cool at 100% of the BTUh capacity until the space reaches the required temperature.
  • Single-Stage - When the thermostat calls for cooling, the air conditioner will cool at 100% of the BTUh capacity until the space reaches the required temperature.

With more stages of cooling, comes more consistent temperatures and lower energy bills since you are using less of the total cooling capacity of the system. For a helpful illustration of the differences between these different types, watch the video included below:


As you decide which Lennox air conditioner you would like to install, you can use these terms as a way to guide your discussion with our team. We offer many different models with all sorts of benefits for your home and family. Let us give you a free estimate today, click below to get started!

"At Paul's, we believe heating and air conditioning can be done in the most professional, timely and effective manner possible. If we can repair what you have, we'll do that. If not, we'll find something that makes sense for your home and your budget. That's our promise, the Paul's Promise."