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The Ins and Outs of Air Conditioning

Shannon Jones

Shannon Jones has been selling real estate since 1998 and specializes in listing and marketing homes...

Shannon Jones has been selling real estate since 1998 and specializes in listing and marketing homes...

Jul 11 12 minutes read

Summer is here in beautiful Southern California, but is your air conditioning unit up to speed? Or maybe you don’t have an AC unit at all - how do you know where to start? We have compiled a complete guide of Air Conditioning, covering everything from how it all works to what options are available. So don’t sweat it! You’re sure to stay cool and comfortable all summer long.

How it Works

You probably know how to work your thermostat, but do you know how your AC really works? Though there are several different types of AC units, the basic system is the same. Knowing the basic ins and outs of the system can help you troubleshoot any minor problems you may encounter.

Air conditioning works by moving the hot air inside your home to the outside. There are four main parts to an AC unit: the compressor, the condenser coil, the expansion valve, and the evaporator coil. The compressor and condenser coils are all located in the condensing unit - or better known as the big noisy box in the backyard. Running through the whole system is a liquid called refrigerant, which is essentially the “blood” of the whole AC unit.

The Compressor is the “heart” of the system. It pumps the refrigerant throughout the various components. As it does so, the refrigerants change from a low-pressure warm vapor to a high-pressure hot vapor. The refrigerant becomes even hotter than the outside temperature.

From the compressor, the hot refrigerant vapor travels to the Condenser Coils. Condenser coils have metal fins (like the front of a car radiator), which conduct heat. So as the refrigerant vapor passes through the coils, it is cooled. A condenser fan is used to speed up the cooling process, and it blows air over the fins. As this happens, the refrigerator vapor changes into a hot liquid.

The hot liquid travels to the Expansion Valve, and it is here that the real cooling process happens. The expansion valve is a tiny opening that the hot liquid is forced to pass through. Given the high pressure and the small opening, the hot liquid emerges as a cool mist on the other side. This is a natural property of gases: when it expands, it cools.

Once through the expansion valve, the cool liquid runs through the Evaporator Coil. Hot air from your home blows across the evaporator coil. Since the liquid inside the coil is cool, it absorbs that heat. Evaporation of the liquid occurs, changing into a cool gas. This cooler air is then blown into your home through the vents, while the heat absorbed in the coil is transferred outside.

Preparing Your AC for Summer

Now that you know about how your air conditioning system works, it is time to make sure it is up to par for the approaching summer months. There are several simple things to help prepare your unit for summer, and these, in turn, will help lower your cooling costs. It is best to tackle these problems in the spring, so you are ready when the heatwave hits.

As a safety note: turn off power to the unit before working on it.

  1. Clean or Replace the Filters
     This is one of the most important steps for AC maintenance, and luckily it is also one of the easiest. Most systems have a replaceable or reusable filter. It is important to clean or replace all filters, so they do not get clogged with dust and debris. If this happens, airflow will be restricted which will reduce efficiency, and may also circulate dust around your home. The US Department of Energy suggests that you replace filters every two months to keep your AC running smoothly.

  2. Clean the Condensation Lines
     The condensation line is a pipe that carries condensation away from your air conditioner. If not looked after, these pipes can become clogged, and may even back up into your home. To check these lines, all you need to do is find where the pipe drains out, and make sure it is draining properly. The drain is often located above the furnace. Flushing one cup of chlorine bleach down the AC drain followed by a gallon of water should keep the drain cleared throughout the summer.

  3. Clean the Fins/Condenser Coils
     As mentioned before, the condenser coils have metal fins, much like those on a car radiator. Since the coils and fins are outside, they are susceptible to collecting dust and debris throughout the year. Cleaning the fins will help your unit run more efficiently. Use a toothbrush or a small car cleaning brush and gently run the brush over each fin. They are thin metal, so be careful not to bend or damage the fins. If there is stubborn debris, spray on a commercial AC coil cleaner (be sure not to spray the electrical components) and gently spray off with a nozzle-tipped hose.

  4. Clear Debris from around the Outside Unit
     Throughout the winter, leaves, dirt, and debris may have collected around your condensing unit. Make sure to clear away anything that may be harmful to the unit or that may restrict efficiency such as leaves, dirt, weeds, vines, etc. Make sure you check for debris at least once a month during the summer as well to keep your unit running smoothly. To prevent build up in the future, consider investing in a plastic tarp to cover your unit throughout the winter or when not in use.

  5. Check the Concrete Slab
     This may be a less obvious maintenance check, but inspect the concrete slab that your condenser unit is placed on. Ensure that it is level and not damaged, or this can have a negative effect on your AC unit’s efficiency. If the slab is not level, it is easy enough to add gravel underneath to adjust it. If it is damaged, you may have to call in a professional to help you fix it.

  6. Inspect Ductwork and Refrigerant Lines
     Before turning on your AC unit, inspect the ductwork for leaks. Check for disconnected joints, separated pieces, or small holes. Many of these problems can be fixed easily, but they can make a huge difference in your unit’s efficiency. According to the University of Florida, “Leaky ducts make your HVAC work much harder — ducts leaking just 20% of the conditioned air passing through them cause your system to work 50% harder.” The same goes for the refrigerant lines. Refrigerant lines should be insulated. If they are not, or if some of the insulation is damaged, the unit will not be performing at its best. These fixes though will have to be done by a professional.

  7. Check Air Vents around the Home
     As you are doing your rounds, inspect the air vents around your home. Ensure that there is nothing blocking them (such as drapes, toys, furniture, etc) so the maximum amount of airflow will be received.

  8. Install a Programmable Thermostat
     Believe it or not, an outdated thermostat may be affecting your AC’s efficiency. A programmable thermostat will allow you to set specific times for when you need more or less air conditioning. For example, set the thermostat to reduce the amount of airflow when you are away at work, and to increase the amount just before you get home. These kinds of settings will help with your cooling costs throughout the summer.

  9. Know When it’s Time to Replace
     Sometimes, maintenance and repairs just aren’t going to cut it anymore. Most AC units, even if well-maintained, only have a life span of about 10-15 years. Thinking of replacing your AC unit may be daunting, but sometimes it will actually save you money in the long run. According to Energy.gov, even if an air conditioner is only 10 years old, you can “save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model.”

Home Air Conditioning Options

There are several different types of home AC units on the market these days, so how do you know which one is best for you?

Central Air Conditioning

Central AC is one of the most commonly thought of systems when it comes to home cooling. It is one of the most effective and efficient cooling system options when installed and used correctly. With central AC, cool are is circulated around your home through the air ducts, creating a pleasant, even temperature throughout. There is the option for dehumidifiers and extra filtration as well, which can help improve your home’s air quality. Oftentimes, central air conditioning is installed as part of an HVAC (Heating Ventilation and Air Conditioning) system which includes the furnace, so the system can create warm air for winter as well as cool air for summer.

Ductless Mini-Split Systems

The split systems get their name because they have two major components, with one being outside the home and one being inside. In a ductless system, the two components are not connected by ductwork, but rather by a small conduit with refrigerated and electrical lines. The indoor unit is normally installed on the wall or ceiling, while the outdoor unit is often mounted under a window on the exterior of the home. Mini-split systems, as the name implies, are not full-scale units. They are most often used to cool one or two rooms. Ductless mini-split systems are ideal choices for older homes since they do not require a lot of extra space or renovations.

Solar Air Conditioners

Solar air conditioners are just as they sound. It is a traditional air conditioning system that uses solar energy to cool your home. Not only is this option environmentally friendly, but it is a method that will save you money in the long run. Any energy produced that is not used to power your AC unit can also be used to power electronics, appliances, and possibly even sold back to your power company. With the solar option, you need to research the best solar options for your home. (*insert link to the Solar Panel blog*)

Costs of AC Units

For an easy answer: the typical range to install a new air conditioning unit is between $3,000 - $7,000. This does not include window AC units, which typically cost around $300, but is more focused on actual AC systems. However, like most things, the cost of air conditioning units is determined by a variety of factors. 

The first major factor is the size of your home. The larger the home, the more cooling power you will need. This is measured in British Thermal Units (BTUs)/hour. A BTU is defined as the amount of energy needed to cool or heat up one pound of water by one degree Fahrenheit. Contractors also do what’s called a “load calculation” to determine what is the proper AC unit for your home. In addition to the size of your home, this calculation factors in the shape and orientation of your home, as well as climate. Though it various contractor to contractor, and home to home, the general rule is that every 500-600 square feet of space require one ton of cooling.

As for the actual cooling unit, that will cost you between $2,000 - $3,500. Here are some average costs of air conditioning units from various manufacturers (listed in alphabetical order):

  • Aire-Flo -- $1,700

  • Amana -- $2,600

  • American Standard -- $3,200

  • Armstrong -- $2,000

  • Bryant -- $2,200

  • Carrier -- $3,200

  • Coleman -- $1,700

  • Comfortmaker -- $1,700

  • Frigidaire -- $2,900

  • Gibson -- $2,300

  • Goodman -- $2,100

  • Heil -- $2,600

  • Lennox -- $3,400

  • Payne -- $1,400

  • Rheem -- $2,500

  • Ruud -- $2,400

  • Tempstar -- $1,800

  • Trane -- $3,300

  • Whirlpool -- $1,900

  • York -- $2,800

(*information from www.homeadvisor.com)

In addition to the AC unit itself, keep in mind that you will also be charged for labor costs and materials involved in installation (such as the chemicals needed or ductwork). Some contractors will allow you to buy the air conditioning system yourself, or to use existing heating ductwork within your home. If you are able to do either or both of these things, it will help cut down on your total cost.

So bring on the summer months! Air conditioning units are not as complicated as they may seem. With a little guidance on what system is best for you home or a little cleaning of your existing unit, you can have a cool and refreshing home all summer long.


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