Central Air Conditioning Systems

Central Air Conditioning Systems often go by many names, regardless of what you call them their basic components and how they work remain the same.  Here’s the basics:

  • Central air conditioners circulate cool air through a system of supply and return ducts. Supply ducts and registers (i.e., openings in the walls, floors, or ceilings covered by grills) carry cooled air from the air conditioner to the home. This cooled air becomes warmer as it circulates through the home; then it flows back to the central air conditioner through return ducts and registers.
  • Air conditioners help to dehumidify the incoming air, but in extremely humid climates or in cases where the air conditioner is oversized, it may not achieve a low humidity. Running a dehumidifier in your air conditioned home will increase your energy use, both for the dehumidifier itself and because the air conditioner will require more energy to cool your house.

Types of Central Air Conditioning Systems:

  • Split System -In a split-system central air conditioner, an outdoor metal cabinet contains the condenser and compressor, and an indoor cabinet contains the evaporator. In many split-system air conditioners, this indoor cabinet also contains a furnace or the indoor part of a heat pump. The air conditioner’s evaporator coil is installed in the cabinet or main supply duct of this furnace or heat pump. If your home already has a furnace but no air conditioner, a split-system is the most economical central air conditioner to install.
  • Package Unit – In a packaged central air conditioner, the evaporator, condenser, and compressor are all located in one cabinet, which usually is placed on a roof or on a concrete slab next to the house’s foundation. This type of air conditioner also is used in small commercial buildings. Air supply and return ducts come from indoors through the home’s exterior wall or roof to connect with the packaged air conditioner, which is usually located outdoors. Packaged air conditioners often include electric heating coils or a natural gas furnace. This combination of air conditioner and central heater eliminates the need for a separate furnace indoors

Cost of Central Air Conditioning Systems?

  • Most homeowners report spending between $3,735 and $7,185 to have Central Air Conditioning System installed.  Your total cost for the job will depend on the type of system you choose, indoor air quality devices, SEER Rating, Size, code requirements, and duct work required.
  • The best cooling unit for your home will be the most energy efficient and the least expensive to run. Home air conditioner professionals help determine this factor in their load calculations, but the next step is looking at the energy efficiency ratio (EER) and seasonal energy efficiency ratio (SEER) ratings of cooling units.

What do SEER and EER ratings mean?

Here’s what you need to know about these two units of efficiency:

  • SEER - The SEER is determined by the cooling output during the winter divided by its electric input during the winter. The higher the SEER rating, the more efficient it will be. Cooling units in the desert southwest specifically must have a minimum SEER of 14, according to U.S. standards, so if you live in a home with a system installed before then, consider having it replaced. SEER 14 units increase home efficiency by 30 percent
  • EER - An EER certifies the cooling efficiency of HVAC units. It’s calculated by the rate of the cooling in British thermal units (BTUs) per hour and divided by the rate of energy input in watts at a specific temperature. The calculation goes as BTUH/WATT at dry bulb (db) versus wet bulb (wb) temperatures. The optimal rating for a cooling unit is about 80db/67wb inside and 95db/75wb outside.

Warranties for Central Air Conditioning System

  • Any newly installed air conditioning unit will come with a manufacturer’s warranty. The warranty’s length will vary depending on the manufacturer. Warranties generally last from five to 15 years; it’s safe to expect an average length of 10 years. The manufacturer’s warranty covers the equipment and parts in the machine. There is also the contractor’s warranty, which covers the labor for A/C unit repairs and additional work such as encasing the air conditioner in protective metal, wiring it to the home and so on. Products with indoor air quality (IAQ) modifiers have a separate warranty that’s less than that of a central A/C unit, so keep that in mind when investing in such products. You may also invest in an extended warranty, which can cover:
    • Cost of replacement parts
    • Additional years for repair costs by a third party (i.e., no out of pocket expenses)
    • Coverage by the manufacturer

Energy Savings with Central Air Conditioning Systems

  • Central air conditioners are more efficient than room air conditioners. In addition, they are out of the way, quiet, and convenient to operate. To save energy and money, you should try to buy an energy-efficient air conditioner and reduce your central air conditioner’s energy use. In an average air-conditioned home, air conditioning consumes more than 2,000 kilowatt-hours of electricity per year, causing power plants to emit about 3,500 pounds of carbon dioxide and 31 pounds of sulfur dioxide.
  • Today’s best air conditioners use 30% to 50% less energy to produce the same amount of cooling as air conditioners made in the mid 1970s. Even if your air conditioner is only 10 years old, you may save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model.

Choosing the right contractor to install your Central Air Conditioning System

  1. Be wary of contractors that give estimates over the phone!  Just as no two automobiles are the same, no two air conditioning units are the same.  Be wary of any HVAC contractor that tries to give you an estimate or a bid over the phone.  There are far too many factors to take into account that a technician cannot see over the phone:  How is your ducting?  Are there the proper amount of registers per room?  What type of insulation do you have?  What type of windows do you have?…and a dozen other factors…and after all of that, a trained HVAC contractor will then do a Manual-J calculation for your air conditioning system.  None of this can be done over the phone, so again, if someone gives you a bid over the phone, they are either inexperienced, or are trying to gain your business without using the time and gas required for a visit.  When they get there, also be wary of anyone who gives you a bid without properly surveying your house.
  2. Be careful of any HVAC contractor that replaces your old air conditioner with the same type of unit as before. The average air conditioning unit lasts 10-15 years.  Is a 1990 Ford F-150 the same as a 2005 Ford F150?  It is the same with your air conditioner.  A properly trained HVAC contractor will recommend several options to bring your home up to date, and increase the efficiency of your home. If they try and sell you an older model, they are likely trying to unload some of their own inventory.  That is why One Hour Air Conditioning and Heating keeps minimal inventory; we will customize the air conditioning unit for your home, and use the most current, energy efficient units on the market.   Make sure your contractor buys a system new for your house, instead of using older inventory.  It is pretty rare to have the exact system you need for your home just lying an a warehouse, and no not all AC units are the same.  In fact, choosing the proper size is far more important than the make and model.
  3. Your HVAC contractor should be registered with the Arizona Registrar of Contractors – https://roc.az.gov – Unfortunately, many HVAC contractors claim to be licensed, but are actually working under the radar.  There is too much at stake, and a licensed HVAC contractor is licensed to manipulate gas lines as well as electrical and plumbing applications – we have to be experts in each to get properly licensed.  You don’t want someone who isn’t closing off your gas line, or properly disposing of refrigerant.  It is a huge problem in Yuma County and is tantamount to a doctor operating without a license.  A contractor should have their license number clearly marked on most, if not all, of their literature and on their website.  Without a license, there is no insurance that the job will be done properly or that you can take recourse if it isn’t!  Don’t trust anyone who doesn’t have a license.  Period
  4. Your HVAC contractor should give you a written bid or estimate - Some people like to give you a bid via a “verbal contract.”  Although this is accepted in Arizona as a legal, binding contract, try and prove it in court and you will see why some contractors do this.  In short, always get it in writing.  Any reputable HVAC contractor will give you a written bid that they will adhere to.  It should include a list of everything that will be done, as well as the price.
  5. Be Careful About Going with the Lowest Bidder…It Costs More in the Long Run. – It’s heartbreaking when we come across someone who just had a new air conditioner installed, and they are calling us out to see why it stopped working.  Unfortunately, about 25-30% of our residential business comes from fixing botched installations from “bargain contractors.” Never to skimp on HVAC.  Think about it, it is literally the only mechanical system in your house.  It is a machine with moving parts that will be running for 10 or 15 years, and if it isn’t installed properly, it will do one of two things:  either it won’t keep your home properly cooled or heated, or worse yet, it will fail altogether.So how do these bargain contractors afford to install a new unit for $1,000 less than all your other bids?  It is becoming more and more prevalent in Yuma County, unfortunately, and it’s simple…as sad as it is, they are a couple of guys in a truck, who are unlicensed or using someone else’s license.  They are using stolen equipment from a new construction site, or they bought used equipment off of someone and are passing it as new.  If it’s too good to be true, it is, and no matter what anyone tells you, you can’t even buy proper equipment and materials for some of the prices being quoted for the entire job, let alone pay for skilled technicians or liability insurance.  So, be careful and pay attention.

    What do you do?  Get multiple bids, and go with your gut – ask, who is going to do the best job?  It is always cheaper in the long run to go with the reputable contractor up front, even if they are a bit more expensive, the real HVAC contractors always are.  You can’t use unskilled laborers to install an air conditioner.  Otherwise, you’ll spend $2,000 – $3,000 for us to fix the problem, and since we are taking over the job and attaching our reputation to it, we will literally need to uninstall and reinstall everything to make sure that it is done properly…that’s assuming you don’t need new equipment.  Moral of the story…if you forget everything else about this article, remember this: just do it right the first time.

Get a Free quote on installing you own Central Air Conditioning System

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