As you shop for a new air conditioner, you have undoubtedly noticed a rating called BTU. This rating commonly accounts for the major difference in the price of units. To understand the difference in the price of air conditioning units, you should know the answers to common questions. Keep reading to learn about BTUs, their importance, and how to select the right rating for your home.
The British Thermal Unit
BTU stands for British Thermal Unit and is the amount of energy needed to raise one pound of water by one Fahrenheit degree. This is part of how you determine the cooling capacity of a particular air conditioning unit.
In central air systems, you may see the capacity discussed in terms of tonnage. This is just a simplified way of thinking of BTUs. One tonne of cooling capacity is equal to 12,000 BTUs. In other words, it can transfer enough heat to raise 12,000 lbs. of water by one Fahrenheit degree.
One important distinction is that the BTU rating is dependent on the system running at peak operational capacity. The condition of the unit, how well it is maintained, the air quality, and other factors may reduce the effective capacity of the cooling unit.
Getting the Right BTUs
Given that BTUs indicate how much cooling capacity your system has, it is reasonable to think that bigger is better. However, let’s explore why being both oversized and undersized is detrimental.
To get the right-sized unit, you start with the size of your home in square footage. When you calculate this number, be sure to consider every room that your HVAC system services, even if it is not included as livable space. This means if your garage, basement, or attic have vents, be sure to include them in your calculation.
The common recommendation is to start with 20 BTUs per square foot of serviceable space. So, if your home has 2,700 square feet, you will want about 54,000 BTUs.
Once you get that base amount, you need to consider the variables. This includes how many people commonly occupy your house and whether your home is shaded. If you have more than two people in your home, add 600 BTUs for every person.
The best way to make sure you have the right size unit is to work with an experienced air conditioning professional. They will help you consider all the important factors to find the right cooling capacity for your situation.
Cautions on the Wrong Amount
When you get a larger system, you are going to pay more for it upfront. Plus, each system has a minimum amount of energy required to operate the system. Larger systems require more energy to run, resulting in significant cost increases just for having the bigger unit.
Larger systems also require the ability to circulate more air to realize much difference in performance. Without this increased airflow, your system is prone to freezing because it cannot absorb enough heat to continue normal operation.
It also runs shorter cycles because it can get cold quickly. Numerous cycles of starting are strenuous on your system, so it causes additional repairs prematurely.
An undersized unit is also a problem for your home. When your system is too small, it must run longer cycles to achieve your goal temperature. This reduces the overall service life of your system and drives up your operational costs. If your unit is too large, it can also run inefficiently.
Humidity & BTUs
Humidity is an important consideration as you think about your air conditioner’s cooling capacity. As the heat increases around Charlotte, the air can hold more moisture. So even though relative humidity may stay about the same, the humidity becomes more oppressive with higher temperatures.
Both the higher temperatures and the higher humidity mean your system must work harder. This is because your AC works to dehumidify the air as it runs, making the air more comfortable.
If your air conditioner is not properly sized for your home to accommodate the humidity levels, it will not be efficient in cooling your space. This is especially true if your system is oversized, causing shorter run cycles. Being the system is not running as long, it leaves the air muggy, making it less comfortable.
Travis Crawford Heating, Cooling & Plumbing has been the go-to company to help people around Charlotte find the right-sized air conditioner. We are also provide heating and AC repair, maintenance, indoor air quality solutions, and plumbing. Call to schedule your new AC consultation with one of our experts today.
