With so many different options, brands, and types of air conditioners available today, you could easily “lose your cool” deciding what’s right for you, your home, and your family. So we talked with our resident expert to help clue us in on what we need to know about air conditioning systems and what to compare when selecting among them.  

First, we’ll look at the three different types of AC units, then at the critical factors to consider in selecting the unit that best fits your budget and cooling needs.

Types of AC Systems

Central Air

When most of us think about getting AC for our homes, it’s a conventional, central air conditioner that we think of – this is also the most common type found in Minnesota homes. Often referred to as central air, these types of air conditioners move cool air through a home with a system that uses ducts and registers to distribute the conditioned air throughout the home. Central air conditioners fall into two types: a split-system unit and a packaged unit.

Keith Hill, the technical support manager at Minnesota Air, says that a split-system is so named because, “it’s two units connected together with copper refrigerant tubing and control wiring.” You can also think of it as ‘split,’ because the system is divided into two spaces – the big metal box that makes up the outside unit that houses the condenser and compressor and the part of the unit inside the home that contains the evaporator.

The Department of Energy says that “in many split-system air conditioners, this indoor cabinet also contains a furnace or the indoor part of a heat pump.”

The other type of central AC, called a packaged unit, gets its name because everything is all in one place. The unit is usually on a roof or spot next to the foundation of the home and the Department of Energy says they are commonly found in small commercial buildings, where ducts come from indoors to connect to the packaged AC unit located outdoors.

According to Keith, this isn’t a very popular option in places like Minnesota. “It’s sort of a central AC system that uses a very large window unit that sits on the ground. They are popular in regions where there are no basements,” he says. 

Room AC

If you’ve lived in a condo or apartment, you’re likely familiar with room air conditioners. These are a very popular option in smaller spaces, apartments, and condominiums. They are compact and packaged, ready to be installed in an existing window or a wall opening, and there is no need for ductwork.

Ductless Mini-Split AC

This air conditioning option has grown increasingly popular over the last few years. According to Keith, ductless mini-split AC is especially popular in homes that have hydronic (hot water) heat and no existing ductwork. “These are quite small units, but they are “split,” with a unit outside and a unit inside on the wall,” Keith says.

According to the Department of Energy, ductless mini-splits are able to go in many locations in a home – perfect for those who want zone heating/cooling. They also don’t need a window or wall cut-out for installation. Instead, the inside unit is typically installed toward the top of a wall. There are styles now that discreetly fit most decors.

Factors to Consider

If you’re in the market for home air conditioning, there are several important factors you’ll want to consider before making your final decision on the type of AC that’s best for your home comfort and your pocketbook. Here are the top four.

Efficiency

The efficiency of air conditioners is measured as the SEER rating. The SEER – or Seasonal Energy Efficiency Ratio – is determined by the Air Conditioning, Heating, and Refrigeration Institute (AHRI), a third-party that calculates the rating. Older AC models will have SEER ratings at 10 or below, but today’s models cannot be below 13 – and the best systems have ratings in the 20s. It’s also important to know that the entire system must be energy efficient to actually uphold the SEER rating.

“When comparing efficiency, make sure you are not just looking at the unit’s nominal efficiency. It takes a matched system to achieve the rated efficiency – a matching outdoor unit and indoor coil,” says Keith. “As an example, there are units with a nominal efficiency of 16 SEER, but realize an actual efficiency ranging from as low as 13.5 to an even higher value of 17, depending on the evaporator coil it’s paired with.” Keith says customers should make sure they know what they are buying by asking for the AHRI certificate that shows the matched rating of both the coil and the outdoor unit. 

Central and mini-split systems are quite efficient. By comparison, the efficiency of room ACs “is generally lower than that of central air conditioners,” according to the Department of Energy,

Furthermore, Keith says that when compared with window units, split systems are far more effective in moisture-removal: "Window air conditioners tend to remove the least amount of moisture as compared to all other types of air conditioners. And since humidity removal is a big part of air conditioning (many would say the most important) I would lean towards a split system where possible."

Ease Of Maintenance

Don’t just focus on efficiency. Having an AC that is easy to take care of is also a very important thing to compare. Keith says that ease of maintenance and serviceability shouldn’t be ignored when shopping for a new AC system.

“Whether you plan on doing the maintenance yourself or hiring a pro, if it’s easier to clean your AC unit, that will save you either your time or your money,” he says. “The size of the unit may also matter if you want to conceal the unit with landscaping.” Remember that where you plan on placing the outdoor unit is important not only in how easy it is for you or a technician to access, but also for its efficiency. You can read more about the importance of AC clearances here.

These days central and mini-split systems are pretty easy to maintain, requiring regular filter changes and recommended annual inspections. Room ACs are also easy to maintain but keep in mind that many homeowners prefer to remove or cover them for the winter months.

Noise Levels

Finally, make sure you take into account the sound levels that the air conditioner makes when running. “If the unit location is such that it may be objectionable to listen to – such as outside a bedroom window, or near a patio or deck, or maybe your neighbors’ bedroom window – then low sound levels should be important to you,” says Keith.

Room ACs also tend to make more noise than central and mini-split systems, although that may or may not be a factor, depending on your personal sensitivity to noise levels. In general, today’s models can run pretty quietly, but you get what you pay for. It’s usually the cheaper, bargain models that will run louder than the others.

Cost

Room ACs are the most affordable and the easiest to install, making them overall the least expensive of the three types. When it comes to central and mini-split systems, the costs can vary widely depending on the size of your home, if you need new or additional ductwork (for central), or how many rooms you want to cool (for mini-split).

If you’re considering either a central or a mini-split system, your best bet is to consult with a reputable HVAC pro. They’ll be able to assess your needs and make recommendations based on that and your budget.

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