4 Questions to Ask to Make Sure You Buy the Right Air Conditioner

Buying a new air conditioner is a large purchase that we hope will be well worth the investment for years to come. In Arizona, our air conditioners get heavy use for much of the year, so we need to be sure we’re making the right choice when purchasing a new one.

Here are four questions to ask to help you decide on the right air conditioner:

  1. What size air conditioner do I need for my home?

Buying the correct size air conditioner is crucial for maximum cooling efficiency.

If you buy an air conditioner too large for your home, the compressor will have to turn on and off more than it should, meaning higher operating costs and more wear and tear on the system.

A too-large air conditioner won’t remove as much humidity from the air as a correctly-sized system.

A unit that’s too small won’t get your home as cool as you’d like on the hottest days.

It helps to understand BTUs when choosing a new air conditioner.

BTUs, which stands for British Thermal Units, is a measurement of heat energy that will help you determine the correct size air conditioner to buy.

When applying BTU measurements to air conditioners, the BTU number refers to the amount of heat that the air conditioner can remove from the air in one hour.

Residential air conditioning systems generally have a rating of 12,000-60,000 BTUs.  The square footage of your home, the floorplan, the ceiling height, and whether it’s a one or two-story home all factor into the number of BTUs your new air conditioner should have.

A west-facing home with lots of sun exposure may require more BTUs, while a well-insulated house may require less.

As a rough estimate, a home of 1,500-2000 square feet would need an air conditioner with 30,000 BTUs, and one with 2,000-2,500 square feet would require 34,000 BTUs.

HVAC professionals often use a calculation called the Manual J Load Calculation, which considers your home’s size, layout, and other factors in determining what size air conditioner is best for your home.

While you can estimate what size air conditioner is the best choice, it’s best to consult an HVAC pro for guidance.

The experts at Chas Roberts can help you choose the correct size air conditioner to keep your home cool.

  1. What is SEER, and should I consider it in deciding what air conditioner to buy?

The Seasonal Energy Efficiency Ratio is known as SEER, and it’s used to indicate an air conditioner’s efficiency and performance.  The SEER rating shows how much energy an air conditioner will use over one year.

According to the U.S. Department of Energy, even if your air conditioner is only ten years old, you may save 20-40% of your cooling energy costs with a new, more energy-efficient model.

So yes, you should consider SEER in choosing a new air conditioner as it’s an essential indicator of energy efficiency.

Generally, the higher the SEER, the less energy the air conditioner will use to cool your home.

The categories for SEER ratings for cooling systems are:

  • Baseline efficiency: 13-16 SEER
  • Mid-efficiency: 16-18 SEER
  • High-efficiency: 20+ SEER

In Arizona and other states with long hot summers, the Department of Energy has set minimum standards that new air conditioners must have a SEER rating of 14.

That means a new air conditioner you buy now will be at least 14 SEER.

As of January 1, 2023, the minimum SEER rating required for new air conditioners sold in Arizona will rise to 15.

Other variables influence the best SEER rating for a new air conditioner for your home, including your comfort level, how low you set your thermostat, and how much you run your air conditioner.

A 16 SEER A/C unit uses about 13% less energy to produce the same amount of cooling as a 14 SEER unit, but the upfront cost of a 16 SEER unit is higher.

Many air conditioners 16 SEER and higher also have a two-stage compressor, allowing the unit to better adapt to conditions in your home and run at a lower speed. Since a 16 SEER unit can run at a lower speed, it may also be quieter.

Units with a two-stage compressor are also better at reducing the humidity in your home.

When deciding on an air conditioner with the best SEER rating for your needs, you should consider all the variables.

  1. Are Energy Star models more efficient?

Energy Star is a government-backed symbol for energy efficiency, and Energy Star products are more energy-efficient and can save you money. They can also help protect the environment.

An Energy Star system meets or exceeds EPA energy requirements, and Energy Star air conditioning systems have a SEER rating of 15 or higher.

According to the energy.gov website, Energy Star qualified central air conditioners are 15% more efficient than standard models, and Americans purchased more than 300 million Energy Star products in 2019.

Energy Star qualified air conditioners are certainly worth considering for maximum energy savings.

  1. Will a new air conditioner work with my home’s existing ductwork and thermostat?

Unless the ductwork is in terrible condition, a new system will generally work with the existing ductwork in your home. A qualified technician should inspect the ducts to see if any repairs are needed.

A new air conditioning system can’t work efficiently if the ducts are leaky.

However, if you currently have an older manual thermostat, it’s time to upgrade to a new programmable model.

The U.S. Department of Energy states that you can save as much as 10% on your energy bills by installing a programmable thermostat.

A programmable thermostat gives you precise temperature control throughout the day, reducing the amount of time your air conditioner runs. That means saving money on energy costs and reducing the wear and tear on your system.

If you’re buying a new air conditioner, it’s an ideal time to install a programmable thermostat.

A Chas Roberts professional can help you choose the best programmable thermostat for your new air conditioner.


The best time to buy a new air conditioner is before your old one gives out on a hot summer day. A new air conditioner will be more efficient than your old one and save you money in energy costs.

An HVAC pro can help you decide on a new energy-efficient air conditioner for your home that will keep you cool for years to come.

Chas Roberts is the largest and oldest residential HVAC company in Arizona and has been family-owned and operated for over 75 years. Contact us for reliable quality service.