Understanding HVAC Guidelines
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Understanding HVAC Guidelines

Once I purchased my first home, I realized that I needed to do my part in caring for my home appliances. In addition to reading the user manuals for my kitchen appliances and state-of-the-art plumbing system, I realized that I also needed to do a little research about HVAC. Because I had no experience with HVAC systems, I called out a professional to teach me a thing or two. It was fascinating to talk with him, and I was able to take notes about all kinds of important topics, such as maintenance, troubleshooting, and even shopping for a new system. This blog is all about understanding HVAC guidelines.

Understanding HVAC Guidelines

The Importance Of Sizing Your Central Air Conditioner Correctly

Marilou Girard

Size matters when it comes to choosing a brand-new central air conditioner. Unfortunately, many homeowners tend to overestimate or underestimate how much cooling capacity their home actually needs. The end result is a central A/C solution that doesn't work as effectively as it could if it was sized correctly. Knowing how to estimate your home's true cooling needs can help you save money and headaches in the long run.

What Happens When Your A/C Is Too Large

A lot of homeowners still believe that "bigger is better" when it comes to their air conditioning. This train of thought usually stems from worries that they'll end up with too little cooling capacity. Many HVAC contractors are also guilty of using the rule of thumb for estimating HVAC size -- 1 ton (or 12,000 BTU/hour) of air conditioning for every 400 square feet of building area. It's quicker and easier than making proper calculations, but it often results in massively oversized A/C units.

An oversized A/C unit will cool your home rapidly, but it won't run long enough to properly dehumidify the air. This results in a room that's cool but feels clammy, damp and generally uncomfortable. The A/C unit will also turn itself on and off in a very short amount of time in an effort to maintain current temperatures. This can add serious wear and tear on the A/C unit, shortening its lifespan.

Oversized A/C units also use more energy than is necessary to keep your home cool, resulting in higher energy costs throughout your A/C system's lifespan.

What Happens When Your A/C Is Too Small

Many homeowners also skimp on their central A/C needs, usually under the mistaken belief that a smaller A/C unit is more energy-efficient. But an undersized A/C unit can have its own set of drawbacks. For starters, it's not out of the ordinary for an undersized A/C unit to run all day long just to keep your home at a certain temperature. This can cause additional wear and tear on your A/C unit and eventually lead to a shorter operating life.

Higher cooling costs are another drawback of operating an undersized A/C. Since your A/C unit has to run longer to cool your home effectively, it also needs more energy to get the job done. The higher energy consumption of an undersized A/C unit can cause your monthly energy bills to increase.

Ways to Make Your Next A/C Purchase Just Right

The best way to size up your home's cooling needs is to have your HVAC contractor perform a Manual J load calculation. By using this method, your contractor can determine exactly how much cooling capacity your home needs based on a variety of factors, including square footage, heat gain and loss, window types and even your home's orientation relative to the sun.

Along with a Manual J load calculation, your contractor should also perform the Manual S equipment selection process. This process uses the results of the Manual J load calculation to help your contractor select the best central A/C unit for your home's cooling needs.

If you need to replace your home's ductwork, your contractor can use the Manual D duct design process to create a correctly-sized duct system that takes full advantage of your new central A/C equipment. This process also makes use of the data gained from the Manual J load calculation, along with other factors including air flow rates and friction rates.

Right-sizing your new central A/C unit can do more than improve the overall comfort of your home. It can also help you save money over the long run by reducing your home's overall energy use. A properly sized A/C unit is also likely to last longer and have fewer emergency repairs needed over the course of its life. For more information and help with getting the correct unit for your needs, work with an experienced HVAC company like A One Heating & Air Conditioning