How to properly select AC systems

The Builder's Corner

Proper Air Conditioning System Sizing and A Whole-House Dehumidifier can Boost Comfort in Southwest Florida Homes

By Theo Etzel, CEO
Conditioned Air Corporation

Every Floridian knows that humidity is uncomfortable at times and practically intolerable at others, but did you know that it also affects the performance of your air conditioner?

A big part of an air conditioner’s job is removing moisture from the air, which helps you feel cool. When the humidity is high, your air conditioner has to work harder to keep you cool. But a whole-house dehumidifier assists your air conditioner. Its job is removing the moisture, so the air conditioner just has to keep you cool. With two home-comfort systems — each dedicated to its own work — you will feel more comfortable. In addition, you just might save some money. Why?

· Air that has been adequately dehumidified feels cooler than warm air. You can turn your thermostat up a few degrees and feel just as comfortable.

· Because your air conditioner won’t be working as hard, you won’t be dealing with frequent breakdowns and repairs. Your maintenance and repair costs will go down.

So, should you buy a portable dehumidifier or invest in a whole-house unit? The answer is easy. Portable dehumidifiers suffer from numerous shortcomings. They are noisy, can only dehumidify small areas and frequently turn off, as they cannot run when their drain pans need to be emptied. They’re not a total solution.

Whole-house units, on the other hand, do what their name implies — they keep moisture throughout your home manageable. Moreover, they’re perfect for any home that’s vacant for part of the year — as so many homes here in Florida are. With the dehumidifier running, you don’t have to worry about a musty smell or mold.

Another key factor in your comfort is the proper sizing of air conditioning equipment for your home. It’s important that you familiarize yourself with Manual J. By educating yourself on this valuable load calculation tool and insisting that your HVAC contractor uses it, you’ll enjoy the highest levels of efficiency and comfort possible.

Manual J is a tool that’s utilized by heating and cooling professionals in order to determine the sensible and latent cooling loads of your home. Your home’s sensible cooling load will tell your contractor how much heat your air conditioner should be able to remove from your home on the warmest day of the summer, whereas the latent cooling load will reveal how much moisture it will need to be able to combat under worst-case conditions.

In order to calculate these loads, an HVAC technician must consider numerous factors including:

· Home size in square feet

· House orientation

· Number of windows and window locations

· Number of household occupants

· Local climate

· Heat-producing appliances

· Current insulation levels

Why is Manual J so important?

Many homeowners make the mistake of believing that selecting a large system will cover all of their needs. Unfortunately, this couldn’t be further from the truth. An air conditioner that’s too large for a home’s cooling needs will run inefficiently and drive up energy bills. The system will cycle on and off frequently as it quickly blasts cold air into your house, satisfies the thermostat requirement and turns off again.

In addition to creating efficiency problems, this also renders the system unable to properly dehumidify your home. Ultimately, this could lower your indoor air quality and create health issues as a result of the growth of mold and mildew. Because of this, it’s imperative that homeowners hire a professional to perform a load calculation before purchasing and installing a new air conditioning system.

Conditioned Air can help you choose the right whole-house dehumidifier as well as properly size any equipment selection under consideration. Give us a call. We have served Southwest Florida homeowners since 1962, and we’re happy to help you with all of your home-comfort needs.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, download our free Home Comfort Resource guide at

With offices in Naples, Ft. Myers, and North Venice, Conditioned Air serves Southwest Florida from Bradenton to Marco Island or anywhere in between.

Theo Etzel has been President and CEO of Conditioned Air Corporation of Naples, Inc. in SW Florida since 1995. Theo’s background is in economics and business development and he is also a writer on business management topics and sits on the editorial advisory board of HVACR Business Magazine.

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Comments » 2

MIOCENE (Inactive) writes:

Thanks Theo. -and that part about not getting to LARGE a unit (tonnage) for your home was extremely helpful.

MIOCENE (Inactive) writes:

(TOO large) :-)

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