Central air conditioning has been improving the quality of our lives for well over 100 years. Air conditioning is a system for conditioning the humidity, ventilation, and temperature to maintain a cool atmosphere in warm conditions. We all know that air conditioning has been helping us keep our cool for generations, but there’s a little bit more to it than that.

Types of AC Units

There is not a one-size-fits-all solution for air conditioning. There are 8 different types of AC units depending on your space, budget, and energy consumption.

  • Central Air Conditioner – If you have a large home with ductwork and you want to cool multiple rooms at once, this is the best option.
  • Ductless Mini-Split – If your home doesn’t have ductwork, or you only need to cool a portion of your home, a mini-split system will work great for you.
  • Window Air Conditioner – This is one of the easiest, and most common types of air conditioner. They are best used to cool just one room by bringing cool air inside and blowing hot air outside.
  • Portable Air Conditioner – Similar to a window air conditioner, this is a great option to cool a single room. Rather than being attached to a window, the portable AC can move from room to room.

Types of air conditioning units for residential homes.

  • Floor Mounted AC – Floor mounted air conditioners are like a mini-split but work better for homes that don’t have the space for a wall mounted unit.
  • Hybrid / Dual Fuel Air Conditioner – The hybrid system combines a gas furnace with an electric air-source heat pump to provide the most cost-effective option throughout the year.
  • Geothermal Air Conditioner – This uses geothermal technology 4-6 feet underneath your home to keep it cool. It’s extremely efficient, but also expensive to install.
  • Smart Air Conditioner – A smart air conditioner can be a mini-split, window or portable air conditioner that is connected to Wi-Fi and comes with an app to control your air conditioning from your smartphone.

Types of air conditioning units for residential homes.

How It Works

All 8 types of air conditioners operate on the same basic premise. They remove the heat and humidity from the indoor air and return cold air to the space. The idea is very simple, but the engineering is a bit more complicated. A standard air conditioner or cooling system uses a specialized chemical called refrigerant. Three mechanical components quickly convert the refrigerant from gas to liquid and back again. This process allows the air to be absorbed, cooled, and redistributed. This cycle continues until your home has reached the desired temperature.

How an air conditioning unit works.

Parts of an AC Unit

There are seven major parts and pieces that make up your air conditioning unit. No matter what type of AC unit you use, you’ll find these parts, or variations of them, working together to cool your space:

  1. Evaporator – This is where cooling coils remove heat and humidity from the air, using refrigerants.
  2. Blower – A blower circulates air over the evaporator and dispenses the chilled air.
  3. Condenser – Hot coils release the collected heat into the outside air.
  4. Compressor – This is a pump that moves the refrigerant between the evaporator and the condenser to chill the indoor air.
  5. Fan – A fan blows air over the condenser, for the purpose of dissipating the heat outside.
  6. Filter – The filter of your AC unit is used to remove particles from the air that will be pushed into your home.
  7. Thermostat – Most homeowners think of the thermostat as a separate piece of equipment, but in all actuality, the thermostat is one of the most important components of your AC unit. The thermostat allows homeowners to have total control over the regulation of the amount of cool air that is distributed throughout your home.

Parts of an AC unit. Common AC Problems

In the U.S., air conditioning units are cranked up high from June to September, when the summer season is at its peak. It is usually during this time when problems arise. There can be several problems associated with air conditioners and it is important to give them a good checkup in the spring before putting them back into use. These are common AC problems you may encounter with your unit:

  • Water Leak (Inside the House) – If you see water leaking from your air conditioner’s indoor unit, it’s likely because the condensate drain is clogged due to algae, fungi, or debris. This usually happens when you don’t keep up on your annual maintenance or if the condensate pump is broken.

Water leak from AC unit.

  • Water Leak (Outside the House) – If there’s a puddle of water on hot summer days around your AC unit, it’s likely time to call for an air conditioning technician who can help you replace your dry air filter, broken condensate pan, bad AC seal, or remedy an improper installation.
  • AC Refrigerant Leak – AC refrigerant is a chemical used to cool the air, but sometimes it can leak out of the system, which can be a dangerous situation. Sometimes this can be a minor fix, but it’s best to call a technician to avoid further AC problems.
  • Dirty Air Filter – Your AC filter is responsible for keeping the airflow clean and free from dust and pollutants. If it is clogged, it restricts airflow and makes your system work harder than necessary. Usually, you need to change the filter at least every 3-4 months.

The air conditioning filter is responsible for keeping your air clean so make sure to replace it.

  • Frozen Evaporator Coil – The evaporator coil freezes when your unit does not receive enough air needed to operate. If this happens, the entire unit will shut off. The only remedy is to wait for it to thaw for about 24 hours and call a professional to keep the problem from happening again.
  • Failure of Electric Control – As the air conditioning unit is turned on and off over and over, the compressor and fan will wear out. Corrosive wires or terminals can stop working, the blower or motor can give out. This requires a professional to replace these electrical components.
  •  AC Fan Failure – If the fan on the outside of the house does not work correctly, it can’t move the air efficiently. Sometimes, this can be a simple issue with the wiring of your system. Other times it could be a sign of internal damage. Either way, it’s time to call a professional and get the air conditioner properly fixed.
  • Thermostat – Sometimes the problem isn’t with the AC at all. Instead, it’s the thermostat that ran out of batteries, got switched off accidentally, or changed settings.
  • Breakers/Fuses – The breakers and fuses safeguard the AC unit’s motor or compressor from overheating. If these go out, the AC unit won’t function properly.
  • Capacitors – The capacitor sends a jolt of electricity to activate the motor. Without this, the motors that power the compressor and fans won’t work.
  • Compressor – The compressor moves the refrigerant, without it, you can’t cool the air properly. If you run out of refrigerant, your compressor can seize up. If you have too much refrigerant, it can cause the compressor to fail.

DIY Maintenance Tips

Heating and cooling accounts for over half of your monthly utility bills. Without regular maintenance, this cost can creep up significantly over time. To keep your costs low and efficiency high, keep up on these DIY maintenance steps.

  • Keep grass, weeds, and debris away from the outdoor unit to keep it running as efficiently as possible.

Keep grass, weeds, and debris away from your outdoor air conditioning unit to keep it running efficiently.

  • Change filters regularly to allow the air to flow freely and avoid making your unit work harder than necessary.

Change AC unit filters regularly.

  • Over time, the concrete pad your AC sits on can crack, settle, or sink. If this happens, it puts strain on the coolant lines. If not remedied, it can even tip the unit over and cause more damage.
  • Keep blinds, windows, & shades closed during hot weather. There’s no need to make your system work harder than normal, so do your part to keep things shaded and cool inside.
  • Vacuum indoor vents and keep vents unblocked to help keep the airflow steady. You don’t want to put large furniture or toys right in front of your vents
  • Keep lamps and other heat producing appliances away from your thermostat. This can trick your thermostat into thinking it’s hotter in the room than it really is and kick the AC on more frequently.

When to Repair or Replace

If your AC is acting up, or not keeping up with demand, it might be time for a replacement. But how do you know when a repair will suffice or whether it’s time for an upgrade? These 10 questions can help determine when to repair or replace your air conditioning unit.

1. How Old is Your Current System?

The average system lifespan for an air conditioner in the United States is 15-20 years. Some brands/types may last longer and usually in hot areas, they’ll wear out faster. Still, the general rule is that if your system is over ten years old, it’s time to consider a replacement option.

2. How Expensive (and Extensive) is the Repair?

There’s no need to replace the whole system because of a clogged drain line or a dirty filter. However, if you’re faced with a repair bill that is close to (or more than) 50% of its total value, a replacement may make more sense.

3. Is Your Current Unit Well-Maintained – Or Not So Much?

If you have been faithfully replacing the filter, keeping the outdoor unit free of plants and debris, and had your unit serviced annually – it will likely last much longer than 10 years. One repair may not be worth replacing the whole system if you know it has been well taken care of.

If you’ve neglected regular maintenance, the repair bills may never end, and it might be time to get a new system and increase proper maintenance.

4. How Efficient Is Your Current Air Conditioner?

You should know the SEER rating of your units, which represents the efficiency of your system. The higher the SEER rating, the less energy the system consumes. Upgrading your system to a higher SEER rating can save you significantly each year. If your current units are operating below a 14, you could save between 30-40% per year on cooling costs which is well worth the upgrade.

5. Is Your Air Conditioner Still Running on Freon?

As of January 1, 2020, the refrigerant known as R22, HCFC-22 or Freon was officially phased out. Both production and import of R-22 is prohibited in the US. If your unit is still using this outdated refrigerant, a new system is inevitable and should be installed sooner rather than later.

6. Is Your Current System Matched?

It’s important to replace both the indoor and outdoor units together, at the same time. Replacing only one can result in an equipment mismatch. If they aren’t made to be together, it can cause trouble down the road.

7. Is Your Current System Meeting Your Home Comfort Needs?

If your system is struggling to cool your home on a regular basis, it’s likely time to consider a replacement. It is likely the wrong size for your home, or it may be slowly wearing out and unable to keep up with demand.

8. Could You Benefit from New Technology?

Air conditioning technology has advanced significantly in recent years. Now you can enjoy two-stage and variable speed technology, smartphone apps to remind you when it’s time to change your air filter or clean the condenser and thermostats that adjust the temperature automatically when you leave and when you return home. Sure, these innovations come with a higher price tag, but the energy savings, warranties and rebate incentives may make the upgrade worth it.

9. Are There Rebates or Other Incentives Available?

There are often rebates available in exchange for purchasing higher efficiency AC equipment. If there is a program in your area, and you know your unit is getting older, it might be a good time to take advantage of incentives while you can.

10. How Long Do You Plan to Live in Your Home?

If you are planning to move soon, it may be worth it to repair your unit instead of replacing. However, a new AC can increase your home’s marketability.

How Much Does an AC Unit Cost?

The exact cost of an air conditioner is dependent on several factors including:

  • Capacity/power of the system
  • Efficiency – SEER Rating
  • The HVAC equipment you’re not replacing
  • Modifications to your existing system
  • Line set protection
  • Installation costs
  • Tax credits and rebates

How to calculate the cost of a new unit vs repairing an old unit.

Because there are so many variables that play into the cost of air conditioning, your system could cost anywhere from $4,500 to over $12,000.

How To Choose The Best AC Unit

There are a myriad of options for air conditioning. Choosing the best one for your home can be overwhelming. Here are a few questions to help you choose the best unit for your space:

  • Do you mind heavy installation? – Both central air conditioners and ductless mini split systems require extensive installation that must be performed by professionals.

How to choose the best AC unit for your needs.

  • How important is energy conservation? – If your electric bill is a huge area of concern, you’ll want to choose an AC unit that will keep expenses low like a window or portable AC unit.
  • Do you want a unit that can be easily moved? – If you need a unit that can be moved from room to room, a portable air conditioner is the only way to go.
  • Do you mind a lot of noise? – The decibel scale varies widely in air conditioners. Central air conditioners are the quietest, while portable air conditioners can be as loud as a vacuum cleaner.

FAQs About AC Units

On July 17th, 1902, Willis Carrier invented the first modern air conditioning system.

The average system lifespan for an air conditioner in the United States is 15-20 years.

For summer, the ideal thermostat temperature is 78 degrees. However, this is still too warm for most comfort levels, so many homeowners keep it closer to 74 degrees. You can keep the thermostat lower and still save money by turning it off entirely when you’re away at work or on vacation.

The cost of your AC unit depends on the size, the type, and the cost of electricity in your area. For example: A standard 3-ton AC will use 4.32 kilowatts per hour. If the cost of electricity in your area is $12.65 cents per kilowatt per hour, the cost of your AC is about 55 cents per hour. It doesn’t sound like much, but if you run your unit for 10 hours per day for 30 days, you’re looking at $165 per month.

Keeping Things Cool

Carriers’ invention in the early 1900s changed the world as we know it. Today, 90 percent of homes in the United States use some sort of air conditioning. More than personal home use, air conditioning helped boost manufacturing, enabled the development of shopping malls, transatlantic flight, computers, and servers that power the internet, and led directly to summer movie blockbusters. Our cooling systems still operate on the same basic principles, providing comfortably chilled air to people everywhere. They still must be maintained, cared for, and installed correctly to keep us comfortable all year long.