Sizing, SEER & Selection Basics You Need to Know Before You Buy a New A/C

Fan Blowing

In past eras, people have tried some pretty zany stuff to keep cool.

Long before what we think of today as “modern” air conditioning was invented, our ancestors were doing everything from running cool water through walls to transporting piles of snow from the mountains to try to cool down.

One of the first semi-modern A/C units required horsepower (literally) to work.

And before we arrived at the sleek, high-efficiency units we enjoy today, early inventors sold ice in blocks and even blew electric fans across them trying to come up with something that would stick.

Thankfully, choosing a new air conditioner is much easier today! Learn what you need to know to pick the right unit for your needs!

Air Conditioning Basics & Options

Today’s modern air conditioners can be separated into three main categories or basic types.

The first is called a central or split air conditioner. The second is called a packaged air conditioner. The third is called a ductless air conditioner.

Split A/C

A split A/C is often confused with a mini-split, but these are not the same systems.

Here, the word “split” means that the mechanics required to cool your home or workplace have been split into two separate components – indoor and outdoor.

Inside, this unit has an air handler (also called the blower) and an evaporator. Outside, the unit has a condenser and compressor.

These two components work together with a system of indoor air ducts that conduct the cooled air to each room in your space.

Packaged A/C

Unlike the split central A/C system, a packaged A/C system houses all of the mechanics required to cool your air together in a single component. Because this type of system can be larger, packaged air conditioners are often installed on the roof.

Packaged systems, like split systems, work with indoor air ducts to conduct cooled air wherever it needs to go.

Ductless A/C

A ductless air conditioner, as its name suggests, doesn’t require indoor air ducts to work. This makes ductless systems ideal for smaller spaces, add-on rooms, seasonal dwellings and areas where existing ductwork isn’t efficient at cooling the air.

Ductless systems are small and streamlined and require no floor space – they can just as easily be mounted on a wall or ceiling. Some ductless air conditioners also produce heat, and these are called ductless mini-split HVAC units.

How to Pick the Best A/C for Your Space

In most cases, homeowners and employers who have existing indoor duct systems will elect to install either a split or a packaged air conditioning system. For spaces that do not have ductwork or in cases where installing ducts would be too invasive (such as for a historic home), ductless systems are the clear front-runner.

But whichever system type you pick, you want to look for certain features that can help you control costs and deliver the most efficient cooling throughout your space.

Size matters

If anyone tells you to buy as much air conditioner as you can afford, run, don’t walk, in the other direction. This old-school thinking has saddled many a homeowner with escalating energy bills, humidity issues and continual repairs.

Rather, you want to match the capacity to the size and configuration of your home or workplace. There are two measures of capacity: BTUs and tonnage. You can use either (12,000 BTUs = 1 ton of capacity).

There is a rather complicated calculation HVAC professionals use to size a new air conditioning system properly for a space. But it is important not to skip this step or you may find you’ve just paid for a system that can’t cool your home or office well.


SEER ratings are another important facet of choosing the best new A/C unit for your space. SEER stands for Seasonal Energy Efficiency Ratio. This measurement takes a look at how well an air conditioner performs during the hottest months of the year and compares that performance to every other similar air conditioner on the market.

So if your new air conditioner has a SEER rating of 13, for example, and your neighbor’s identically sized A/C has a SEER rating of 8, this means you will get better energy efficiency (and pay less for energy) than your neighbor will, all else remaining equal.

Energy-saving features

Today’s air conditioning systems really are built with an eye toward reducing energy consumption and helping owners manage their energy use to lower bills.

Programmable thermostat

Most homeowners and employers today are aware of how valuable it can be to have a programmable thermostat and actually use it.

A programmable thermostat is the only thing standing between you and paying to cool an empty home or office!

Some programmable thermostats can also give you monthly energy-use data you can use to program your thermostat for more savings in future months.

Zone control

Ductless air conditioning systems are especially good at giving you individualized temperature control over different parts of your home or workplace.

Energy Star certification

Energy Star-certified systems deliver a higher level of efficient operation to trim your monthly energy bill. On average, Energy Star certified air conditioners use 8 percent less energy to do the same work as non-certified A/C systems.

According to the U.S. Department of Energy, when you choose to replace an air conditioning that is 10 years or older with a newer, Energy Star-certified system, you may save up to 40 percent on your annual energy bill.

Get in Touch

Is your air conditioner ready for its spring maintenance service? Do you need a free quote to install a new system? We can help!

Check us out online or give us a call at 905-549-4616.

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