How to Choose the Right Cooling System for Your Needs

Photo by Andrey Matveev on Unsplash

Choosing an air conditioner can seem daunting, but once you understand the basic questions, it becomes a lot simpler. Follow this guide to learn about each type of system and how to find the best fit for your space, budget, and climate.

Consider Your Space and Climate First 

Every air conditioner functions differently, so climate and space are the first considerations when deciding. For hot, humid climates, centralized AC systems with built-in dehumidifiers are ideal. This is because they not only cool the air, but pull moisture from it as well. For dry climates, evaporative coolers, or swamp coolers, are more effective and cost less.

Heat pumps can also be a great choice for areas with mild or inconsistent summers. Because they heat and cool your home using the same system, you can eliminate the need for a separate furnace or AC system. Another climate-specific system is a variable speed air conditioner. These systems operate best in coastal areas or places with high elevation, as they rapidly adapt to changing temperatures outdoors.

The structure of your home is important, too. If your house has existing ductwork, installing central air will allow cool air to flow consistently throughout rooms using your furnace or air handler. If you don’t have ducts already, consider a mini-split style air conditioner.

Choose the Right System Type for Your Space

You should also figure out what areas of your home you wish to cool. Not every home will need or have multiple types of systems installed. Central AC systems are ideal for larger spaces because they cool your entire house through the furnace or air handler. Split systems, by contrast, have multiple indoor and outdoor units. This allows you to cool multiple rooms without having to connect everything to a central duct system.

There’s also portable air conditioning units. These are perfect for single rooms, and can even be moved to different rooms as you see fit. (They’re great for renters.) A ceiling fan can also cool a room, if all you need to cool is a bedroom at night, or a living room that’s rarely subject to direct sunlight. A room split or multi-split system can cool one or two rooms, making them a great compromise between central AC and standalone units. If you need to cool your whole home, you’ll need multiple multi-split units or go with ducted AC.

Size Does Matter 

When purchasing a cooling system, you also want to make sure you’re getting the right size unit for the space. Getting a system that’s too big for the room will waste energy, while too small will cause your system to run longer without adequately cooling the room.

Several factors play into how you measure for size, including square footage, ceiling height, insulation, windows, and climate. For air conditioners, calculate your expected cooling load (heat coming into your home) on the hottest days of the year. And if you opt for a reverse-cycle AC unit, calculate the heating load as well. For ducted evaporative coolers, you’ll use CFM (cubic feet per minute) to measure rated airflow and calculate against the volume of your home. The easiest way to ensure you get a correctly sized unit is to have an installer come to your home and take measurements before you commit to buying.

Look at Energy Efficiency Ratings 

Saving energy isn’t just good for the planet. It also keeps more money in your pocket each month. Air conditioners have a Seasonal Energy Efficiency Ratio (SEER) rating that measures how efficiently they operate over a cooling season. The higher the SEER rating, the more efficiently your system will run and the less it will cost you to operate. Energy Star rated systems are certified by the federal government as meeting their energy efficiency standards.

You should also inquire about inverter technology with the system you choose. Air conditioners with inverter technology have a compressor that varies its output instead of turning off and on frequently. Not only does this create a more consistent temperature throughout your home, but it saves energy. In general, systems with inverter technology are more expensive than non-inverter models but will save you money on your electricity bill over time.

When specifically looking at air conditioners, you can easily identify which models are most efficient by checking the stars on the rating label. The more stars an air conditioner has, the less it costs to run during its lifetime. If you go with a fan, look for models with DC motors. These fans consume less electricity than AC motor fans and typically provide more fan speeds.

Installation and Long Term Costs 

Installation is another factor that affects your budget. Systems like central air conditioners have higher installation costs due to added ductwork and labor fees. However, they offer efficient cooling throughout your whole home. Mini splits typically cost less to install than central air systems, especially if you don’t already have ductwork. 

Bonus: they operate more quietly and consume less energy.

Window units and portable air conditioners are by far the least expensive types of cooling systems. However, they’re also usually less efficient and more noisy than other options. If you only need to cool one room occasionally, these might be all you need. However, if you live in a climate that requires year-round cooling for your entire home, investing in central air or a mini split system will be cheaper over time.

Real-World Example: Selecting a Cooling System for a Home 

Perhaps one of the best examples of this comes from the U.S. Department of Energy’s Building America initiative.

Building America has conducted research into how various building characteristics and HVAC equipment can impact energy efficiency. One of their findings is that no matter how efficient your air conditioner is, it can’t do its job properly if other elements of the building aren’t up to par.

Take two houses with the same floor area. One is built with superior insulation, energy-efficient windows, limited exposure to the sun and tight construction to prevent air leaks. The other home has older windows, poor insulation values and more exposed area that gets blasted by the afternoon sun.

Simply looking at square footage, you might assume they should both have the same size AC system. However, due to their different construction, their actual cooling requirements could be significantly different.

The same goes for deciding between central AC, mini-splits, portable air conditioners or some other type of cooling equipment. Whole-home air conditioning makes sense if your entire house needs cooling and you have the ductwork available. Mini-splits are ideal if you don’t have ducts or only need to condition specific rooms. Portable AC can help you cool a single room without installing new equipment.

Building America also covers the importance of HVAC equipment matching the building envelope. Adding insulation, limiting unwanted air leakage and controlling solar heat gain can lessen your home’s cooling load.

Tip: Just because an air conditioner is powerful doesn’t mean it’s right for your room or home. Too large and it will cool the space quickly but will remove little humidity from the air while cycling on and off. Too small and it may run continuously without adequately cooling the room.

It’s always best to look at all factors including climate, size of space, insulation, windows, occupancy levels, existing ductwork and more before picking out your air conditioner.

Frequently Asked Questions 

Below are answers to some common questions we receive about how to select an air conditioning system.

What is the most efficient type of cooling system?

There are pros and cons to each type of air conditioner. Here are a few of the most common systems and their best applications:

• Central Air Conditioning: These whole-home AC systems are ideal if you need to cool your entire home and already have ducts installed.
• Ductless Mini-Split: Perfect for homes without ductwork, additions to existing homes or cooling individual rooms.
• Portable Air Conditioner: These AC units don’t have to be permanently installed and are good for cooling a single room or providing temporary cooling.
• Window Air Conditioner: Another option that can be easily installed and removed that is best for cooling individual rooms.

How do I know what size air conditioner I need?

The size of the room you wish to cool is important, but not everything. Ceiling height, insulation, windows, sunlight and your local climate all play a factor into your cooling load.

If you know roughly how many BTUs are required to cool your space, you can begin comparing different air conditioners based on their features, efficiency and price.

Will a bigger AC unit cool better? 

Not necessarily. Like having an AC system that is too small, oversized equipment can be bad.

If your air conditioner is too large for the space that needs cooling, it will cycle on and off more frequently. This causes it to cool the space quickly but may not have enough runtime to properly dehumidify the air. Your room may end up feeling cold and clammy.

An oversized air conditioner can also wear out faster due to the frequent start-stop cycling.

What if my air conditioner is too small?

A small AC unit will likely run continuously in hot weather because it isn’t powerful enough to cool the space quickly.

Not only will your electric bill likely be higher due to it running more often, but your system will also be under additional strain.

Should I get a mini-split or central air conditioner?

Not necessarily. Both systems have their place in the HVAC world. If you don’t have ducts in your home, need to add on to your house or wish to have individual rooms at different temperatures, a mini-split can be a great solution.

However, if you want to cool your entire home using existing ductwork, central air can be a more convenient and cost-effective option.

Are portable air conditioners a good idea? 

Portable air conditioners can be a great choice if you only need to cool one room or require a temporary solution.

Since they don’t have to be installed like many other air conditioners, they’re also a great choice for renters.

Do keep in mind that portable units may not be as quiet or efficient as permanent models.

What is the difference between a mini-split and central air conditioner?

A mini-split system doesn’t require ductwork. Instead, it uses a large compressor/condenser outside your home and one or more indoor air handling units.

Refrigerant lines connect the indoor and outdoor components, allowing cool air to be distributed without traditional ducts.

What are multi-split air conditioners? 

Much like a mini-split system, multi-split air conditioners don’t require the use of ductwork.

However, multiple indoor air handlers are connected to a single outdoor unit. This gives you the ability to cool multiple rooms individually without having to install full ducted HVAC equipment.

How does climate affect my air conditioner? 

Climate factors into your air conditioner more than you may think. An air conditioner in Houston, Texas will have different requirements than one in Phoenix, Arizona.

Humidity levels, outdoor temperatures, weather patterns and ventilation requirements are all important factors to consider when selecting an air conditioner.

Are all inverter air conditioners more efficient? 

Inverter air conditioners have the potential to be more efficient than non-inverter models. Because their compressor can slow down or speed up instead of turning on and off at full capacity, they can react to your home’s changing cooling needs.

Which air conditioner has the best SEER rating?

Seasonal Energy Efficiency Ratio, or SEER, is how the efficiency of air conditioners is measured. The higher the SEER rating, the more efficient the air conditioner should be.

Keep in mind that not every country uses SEER, and some places may have different ratings and metrics for measuring efficiency.

How much does it cost to install an air conditioner?

Air conditioner installation costs can vary wildly based on the type of system you choose, the layout of your property, electrical requirements, ductwork and labor.

While central AC might require new ductwork and installation throughout your home, a ductless mini-split could require less invasive structural changes.

Try to look at the entire cost of owning your AC, not just the purchase price. Installation expenses, electricity usage, maintenance needs, system longevity and even noise levels are all important factors.

Can I just use a ceiling fan instead of air conditioning?

Ceiling fans don’t actually cool the air in a room. Instead, they create better air circulation so your skin can more easily cool itself through evaporation.

In many cases, ceiling fans can be used in conjunction with your air conditioner to allow you to set the thermostat at a higher temperature without reducing comfort levels.

Do air conditioners need ductwork? 

No. While most central air conditioners use ducts to distribute cool air, there are plenty of options available that don’t require ductwork.

Ductless mini-split systems, portable AC units and window air conditioners are all great choices that can cool without traditional duct networks.

How can I lower my cooling load? 

There are many ways to reduce your cooling load including:

• Improve your insulation 
• Seal any air leaks 
• Install window coverings 
• Reduce solar heat gain 
• Increase ventilation 

Reducing your overall cooling load means your air conditioner doesn’t have to work as hard to keep your rooms at the desired temperature.

How do I know how much cooling my home needs?

You can get a basic idea by considering the square footage of your home, ceiling height, window counts, insulation, sunlight levels and climate.

If you need cooling for an entire building or have a more complex property, it’s best to hire a professional HVAC contractor. They can size your home using industry-standard calculations to find your exact cooling needs.

Should I get the air conditioner with the highest efficiency rating?

While higher-efficiency AC units can lower how much you spend on electricity each month, pay attention to how much you’ll spend upfront.

Just because you can afford the highest efficiency air conditioner doesn’t mean it’s the right choice. Be sure to compare your local electricity rates, how often you would run your AC, projected equipment lifespan and more.

Which air conditioner type is the least expensive to operate?

This will vary from home to home and user to user. Just because a system is cheap when you buy it doesn’t mean it will operate at a low cost.

Check the equipment’s efficiency, how well it matches your cooling needs and more. In many cases, spending a little more up-front can save you money over the equipment’s lifetime.

Is central air conditioning more effective for big houses?

Not always. Central air can be an excellent way to cool large spaces because you can use your ducts to distribute cool air.

However, large homes can benefit from multi-zone ductless systems as well. Since you aren’t limited by existing ductwork, zoning different rooms allows for more precise temperature control.

What else should I consider other than price?

Price should always be a consideration, but let’s look at additional things you should factor in when researching air conditioners:

• Installation Cost 
• Energy Efficiency 
• Cooling Capacity 
• Maintenance 
• Noise Level 
• Replacement Filters 
• Warranty 
• Lifespan 
• Electric Usage 

Picking the cheapest air conditioner may end up costing you more over time if it uses more electricity or requires constant repairs.

Do I need to have my air conditioner sized by a professional?

If you’re having a permanent system installed in your home or business, we highly recommend having it sized by a trained professional.

They can account for your building’s cooling load and offer advice about your windows, ductwork, climate and heat gain. Trying to size your air conditioner by square footage alone will often lead to inaccurate estimates.

What mistake do most people make when buying an air conditioner?

Picking an air conditioner based solely on the price tag or your rooms square footage. Just because two spaces have the same square footage doesn’t mean they have the same cooling requirements.

Consider your climate, insulation values, window counts, exposure to the sun, how many people occupy the space and even your electric rates.

Neglecting factors like these can lead to higher-than-expected energy bills and comfort problems.

Final Words 

Remember: there’s no one-size-fits-all solution for cooling systems. What works in Arizona might not work in Florida. Before you make your decision, take inventory of your space, consult with a professional installer for quotes, and use your climate and efficiency ratings to narrow down your decision. A few hours of research now can prevent expensive mistakes and save you from sweltering in the summer.