First Steps for Installing an AC Unit

Reader Contribution by Ashley Morse and The Cooling Company
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Keeping cool during these scorching summer months is more important than ever. Luckily, there are more energy-efficient air conditioning units on the market. Windowsill units are the easiest to handle but have a limited capacity. If you have a larger home, then a central unit is required.

The leanest way to install a central air system is for you to set it up and let the professionals handle all the wiring and dangerous chemicals. The Environmental Protection Agency states that a licensed professional is required to handle the refrigerant for your unit.

Confirm Building Code Requirements (or Limitations)

Three agencies write the residential building code requirements: The IAMPO mainly deals with plumbing, the International Code Council takes responsibility for the safety and building structure, and the NFPA deals with fire safety.

The ACCA is the air conditioning association that works with the ICC to provide the manuals that govern the codes and regulatory designs for heating, ventilation, and air conditioning (HVAC). Manual J has the residential load calculations for the region needed.  Manual D keeps the duct system in compliance, and Manual S governs the equipment selection. These manuals are on the ACCA’s website. See this YouTube video series for what code officials need to know about HVAC.

Load calculations measure heat flow from area to the next, depending on the time of year. These measurements vary between different parts of the home. The windows, skylights, floors, wall panels, the orientation of the home, and the doors all have an important role in the measurements. The Manual J will provide the tables for the best match suitable for your unit.

Incorrectly-sized equipment can leave you with an inefficient system. When choosing a unit, pay attention to the heating, cooling, and blower equipment. Manual S is your reference guide when planning your purchase.

You have the choice of a ductless system, creating the duct system, or renovating older ducts. A good contractor can retrofit a new system with the existing system. Ducts are also responsible for how quiet the unit should be and for cleaning the air. The ducts that you will need are based on the equipment and the load calculations.

If you are paying a fee to the Homeowner’s Association (HOA), then you will have to take into account any aesthetic and noise requirements that they may have. Do your due diligence and procure all the information that you need. Forewarning: If you violate the HOA terms, then they can potentially put a lien on your house.

Preparing the Home

If you are putting the unit on the roof, then check the integrity of your roof. Keeping your roof maintenance up to date will save you on costly repairs. If you are running the unit through your attic, then be sure to clear any clutter that might hinder construction. (Split systems do not need ducts.)

The contractor should know the proper clearance a system should meet. It is good for you to know exactly where to place the AC unit. If you already have a heating duct system, then this can be used for your air conditioning. Also, check the insulation of the home, because proper insulation and even adding insulation to the attic can lower the costs and your carbon footprint.

AC Unit Installation Safety

Your contractor handles the chemicals needed for your unit. Unfortunately, the usual refrigerants used are the ozone-depleting chemicals called hydrochlorofluorocarbons (HCFC). Discuss with your contractor the HCFC-free options that are now available. Also be aware of the possibility of “sun rot” if the unit is installed in the wrong direction. If the position cannot be helped, then consider a form of shading that won’t have your HOA hopping mad.

Installing central air is not a simple task, so having all the information you need is important. Installing ceiling fans, energy-efficient curtains, and maintaining the cleanliness of your unit will keep this project economical and environment-friendly.

Ashley Morse is with The Cooling Company which has provided the absolute best comfort in heating and air conditioning for Southern Nevada homes since 2011.

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