How to Buy Air Conditioners

Updated on February 19, 2014
Cre8tor profile image

Dan has been in the HVAC industry for 22 years with experience ranging from installation and service to sales and distribution.

Are You Considering Buying A/C This Year

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Buying an Air Conditioner is a Big Decision

It's big because it's long term, costly and you probably don't know as much about it as you'd like when making the choice to buy. That's all about to change.

The best way to make any significant purchase is with sufficient knowledge. Buying an air conditioner is no different. This hub will provide you a basic understanding of an air conditioning system's parts and functions, buying considerations and offer tips on how to maintain your new air conditioning unit as well.

NOTE: Though this hub will reference a typical, residential, split system style central air system, the information within is applicable to most other air conditioning system types.

Basic Air Conditioning System Components

Let us start with understanding what the main components of a split air conditioning system are.

Condenser

Condenser
Condenser | Source

Condenser

This is the main functioning piece of the system that is placed outdoors. It's main purpose is to disperse the heat that has been absorbed from inside the home and to condense the gaseous refrigerant back into a liquid so it can be fed back to the evaporator coil. The condenser consists of a large coil surface, a compressor, a fan/motor and various smaller electrical components inside the service panel. (Note: The scroll type compressor has a great reputation.)

Though condensers made and installed today are using the refrigerant 410a, there are still some R-22 units floating around out there. Do not purchase an R-22 unit. This refrigerant is no longer manufactured and very expensive if needed. Also, 410a operates at a much higher pressure than R-22 so the refrigerants cannot be added to systems that are not designed for them.

This evaporator coil is "cased".
This evaporator coil is "cased". | Source
Here is a partial view of what the evaporator coil inside the case looks like.
Here is a partial view of what the evaporator coil inside the case looks like. | Source
The brass fitting shown here contains an orifice type metering device; a simple brass piece with a specifically sized hole in it. A TXV type is more accurate and can adjust to variable pressures and temperatures. You may want request this option.
The brass fitting shown here contains an orifice type metering device; a simple brass piece with a specifically sized hole in it. A TXV type is more accurate and can adjust to variable pressures and temperatures. You may want request this option. | Source

Evaporator Coil

This is the second largest piece of the system that sits on top of your air handler or furnace. Though there are no mechanical parts (except perhaps the metering device) to the coil, it has an important job. As the refrigerant arrives at the coil from the condenser in a liquid state through the "high side" of the line set, the metering device controls the pressure of the refrigerant so that it immediately begins to "superheat" or evaporate inside the larger copper tubing of the coil. Since refrigerant super-heats at a very low temperature, the cool refrigerant and surface of the coil now begin to absorb heat and humidity out of the air that is passing over and through it. The now heat soaked refrigerant is sent back to the condenser through the "low side" of the line set and the humidity, that has collected on the coil like a cold glass of water on a summer day, will collect in the coil pan and be drained to it's chosen destination. This drainage is often passed through 3/4" plastic piping and across the floor to a drain. If you're furnace is not located near a drain, you may want to consider a condensate pump.


Condensate Pump

For those of us who do not like the thought of plastic piping laying where we can trip on it or cannot achieve a slant great enough to carry the drainage away, a condensate pump may be necessary. This little accessory will collect and pump the water vertically and across the ceiling through vinyl tubing to it's final destination. There are many varieties but I suggest one with a cut-off switch that will shut down the system if there is a problem with the pump. This can help to avoid a messy clean up if there is a breakdown with the pump.



What is a Lineset?

Here you can see the line set and the low voltage wiring the furnace uses to communicate with the condenser.
Here you can see the line set and the low voltage wiring the furnace uses to communicate with the condenser. | Source

Line Set

This is simply the copper tubing that carries the refrigerant back and forth between the condenser and evaporator coil.

A/C Condenser Pads

Polymer Type Condenser Pad
Polymer Type Condenser Pad | Source
Styrofoam Type Condenser Pad
Styrofoam Type Condenser Pad | Source

Condenser Pad

The condenser must sit on a flat and level surface. These pads are used to provide that surface once the ground is leveled and keep the condenser from sitting directly on the ground. Might I suggest choosing a long lasting pad made of some sort of solid polymer as opposed to Styrofoam, which can crush, or concrete, which is tough to handle and enhances vibration noise from the unit.

How to Stop Power to Your A/C

Service Disconnect
Service Disconnect | Source

Service Disconnect

The service disconnect is normally mounted to the side of the house within a couple feet of the condenser. This disconnect is used to shut down the power to the unit while servicing. This is also where your fuses are normally located. Air conditioning usually runs on 220/240 volts originating from your breaker panel where the power can also be shut off by it's dedicated breaker. Power from the panel arrives at the disconnect where the fuses can protect the unit from potential electrical overloads that might damage the system. If you have existing air conditioning and your disconnect is in good condition, this will not need to be replaced however, if you are just getting A/C for the first time, you will need this and likely need to have modifications made to your electrical panel as well. Two open breaker spots on your panel are typically needed for powering central air conditioning as well as some window type units.

Thermostat

I think we all know what a thermostat is however this may be a good time to upgrade. The old mercury, turn dial type stat is inaccurate and obsolete. A new digital thermostat will more than pay for itself over time and provide better comfort for you and your home. Going with a programmable stat isn't a bad idea either, just be sure to read your instruction manual carefully or you may find yourself wondering why your system shuts down at 4 a.m. every Wednesday night.

HVAC Buying Tip: Buying Power

Try to purchase your air conditioner and furnace together. There is savings in the way that some work and materials may have to be duplicated to install them separately. This wouldn't include additional trip charges and overhead costs.

Who Should Install Air Conditioning?

Only a licensed and insured HVAC professional with EPA certification should install your new air conditioning system.

Air conditioning is a heavily controlled industry. More specifically, refrigerant is heavily controlled by the EPA. The CFC's (ozone eaters) in refrigerant are not only damaging to the environment but refrigerant can be extremely dangerous to your immediate health and safety. Very severe burns can be sustained when in direct contact with these refrigerants, which are by the way, contained under very high pressures.

Beyond the issue of refrigerants, the proper installation of your new system is more important than the brand you choose. Air conditioning is finicky and if not installed properly, will never function as it should.

So let's say you choose a guy whose done this once or twice and he messes up. Once our uninsured weekend warrior has promoted global warming and returned from the ER, they may also be greeted by the EPA with a warrant and fines in the 10's of thousands of dollars. You on the other hand are stuck with a few grand wrapped up in an air conditioning system that doesn't work, the warranty is void and...is it me or is it getting hot in here?

Go with a pro on this one.

What to Consider When Buying an Air Conditioner

Did I mention it's important to have this work done by a reliable, licensed and insured professional?

Of course there are other things to consider when making this purchase as well. The following are key elements that can make a big difference in cost, future service and even potential tax write offs based on the SEER rating. (Seasonal Energy Efficiency Ratio)


Warranty
SEER Rating
Sizing (Tonnage)
Most systems will come with very similar manufacturer warranties these days. Be sure to find out specifically about the warranty on the compressor and fan motor. These will be your most expensive repairs if needed in the future. Also, ask about any service contract and/or labor warranty that may be offered by your installation company. If there is a reasonable service or maintenance contract available, consider adding it to your purchase.
The SEER rating is given to air conditioning units, specifically the condensor, and describes the efficiency of the unit. The higher the SEER rating number, the more efficiently the system will operate and the more money you'll save on utilities. This will also be the determining factor on whether or not you'll qualify for federal tax credits. Be sure to inquire on this potential tax break.
Air conditioners are sized by what is referred to as "tons". What is important to you here is that the fan on your furnace is paired off properly with the required airflow of the air conditioning system. Know that 400 CFM (Cubic Feet / Minute) is required to be produced by the fan for every ton of air conditioning. (Example: If your salesman says you need 3 tons of air conditioning, then have him to check to make sure your fan is capable of producing 1,200 CFM of airflow.)
Pricing
Location of Unit
Brand
Though you're pricing cannot really be controlled, it can be kept in line. At minimum, 3 quotes should be obtained and compared to insure fair market pricing. Don't be afraid to negotiate with your salesman. Their estimates are not set in stone and will often leave room for them to discount pricing.
Try to locate your condenser as close to the furnace and electrical panel as possible. Do not cover it up with shrubs and plants either. It is important that nothing restricts the airflow to your condenser. These items will also contribute to efficiency and utility savings.
All brands are held to the same standards and reulations. Many are built with the same components and some are even identical with only a different name plate applied. Do some research but again, installation and maintenance will ultimately be more important than branding.
Central Fan
I know we're talking air conditioning but the fan in your furnace is an essential part of this system. If you don't need a new furnace but are interested in energy savings, ask about replacing your furnace fan motor with an ECM type. This can help reduce your electrical consumption year round.

Air Conditioning Maintenance

Once you've purchased your new air conditioning system, maintaining it is of the utmost importance to protect your investment. Proper maintenance and understanding your system will maximize the system's efficiency and minimize the amount of money you'll spend on service. These few things you can do will help save you money now and later.

- Keep your condenser clean and clear of obstruction.

- Check your furnace filter on a regular basis.

- Keep the mileage low on your system. If it's pleasant outside, open the windows.



Be "Cool"

I know it's a lot to consider but with this information, you should feel good knowing that you're going to make an informed decision about your air conditioning purchase. It's "no sweat"!

Questions & Answers

    Comments

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      • Cre8tor profile image
        Author

        Dan Robbins 4 years ago from Ohio

        Thank you Amelia! I appreciate the feedback. Perhaps one of my hvac hubs will be helpful to you again when you need it to thank you more.

      • Amelia Brose profile image

        Amelia Brose 4 years ago from Carlton, Victoria, Australia

        I like your Hub very much. It is very informative It gives complete information about Buying the right Ac for who has any confusion thanks of sharing.

      • Cre8tor profile image
        Author

        Dan Robbins 5 years ago from Ohio

        Thank you kindly.

      • profile image

        i4u 5 years ago

        I loved the description on all the aspects.

        Wonderful writing and voted up.

        Best wishes!

      • Marcy Goodfleisch profile image

        Marcy Goodfleisch 6 years ago from Planet Earth

        I need this hub, big time. My house still has the units it came with about 18 years ago, and I know I'm on borrowed time. So much to learn here! This is helpful, technical and yet understandable, and very comforting to know it's from an expert.

        Voted up, useful and interesting!

      • alliemacb profile image

        alliemacb 6 years ago from Scotland

        Great hub, full of useful information which is easy to follow.

      • wayseeker profile image

        wayseeker 6 years ago from Colorado

        Cre8tor,

        Another hub of just phenomenal practical value. I wish I'd had this information seven years ago when we bought our AC system. It's working fine, and I think we got a fair deal, but it's so much easier to do these things when you know even just a little about them.

        This hub provides all kinds of great information and is detailed without being overwhelming. I missed a lot of the finer points as I went through this time, but I'll be back again the next time we need them replaced--you can bank on it!

        wayseeker

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