Choosing your own air conditioner or heater for your St. Peters, MO home, might seem like a good way to save money. After all, there are a number of big box stores offering HVAC equipment at discounted prices. Unfortunately, these efforts often cause more problems than they solve. If you wind up purchasing a unit that’s too large or small for your home or that isn’t powerful enough, you’ll wind up spending more money in the long run. One large part of selecting HVAC equipment for any environment is making sure that it’s got the right number of BTUs for the intended service area. Purchase your unit from Jerry Kelly Heating & Air Conditioning, and you can be sure that it’s the right fit for your home.

What Is a BTU?

BTUs (British Thermal Units) are a measurement of energy. A BTU represents the amount of heat that’s necessary for raising the temperature of one pound of water by a single degree. With BTUs, temperature changes are measured in Fahrenheit. It takes a minimum of 45,000 BTUs to heat or cool a single 1,500-square-foot home.

All air conditioners and heaters state their heating or cooling power right on their labels, but matching BTUs up with square footage isn’t likely to give you the results you want. When HVAC companies choose heating and cooling equipment for residential or commercial applications, they use a formula that accounts for numerous factors. This formula is known as a Manual J calculation, and using it is a complex process. In fact, there are multiple forms of Manual J software that many seasoned professionals use to ensure accuracy and prevent oversights. Two buildings that both have 1,500 square feet of usable area can have dramatically different needs in terms of BTUs. Things like ceiling heights, window sizes, insulation, and layout matter too.

Meeting Your Efficiency Goals

Another important step in choosing HVAC equipment is making sure that efficiency goals are met. BTUs denote the cooling or heating power of HVAC equipment, but they don’t reflect a system’s efficiency. Thus, you’ll have to understand annual fuel utilization efficiency (AFUE) ratings as well, and you’ll have to combine this knowledge with your understanding of BTUs, property sizes, building layouts and more.

While BTUs reflect the energy output of heating and cooling equipment, AFUE ratings denote how well this energy is used. For instance, a high-efficiency heater that has 100,000 BTUs will use 100,000 BTUs of energy for every hour that it’s in operation. If it also has an AFUE rating of 97 percent, it will use 97 percent of this energy or 97,000 BTUs each hour for the actual production of heat. The other 3,000 will be lost in exhaust gases or by other avenues of waste.

Lower AFUE ratings affect the BTU needs for any home. If you choose the cheapest furnace that you can buy and get one that has an AFUE rating of just 80 percent, your 100,000 BTU furnace will use 100,000 BTUs of energy every hour, but you’ll only get 80,000 BTUs of heating.

BTUs and AC Systems

BTUs are also used to show an air conditioner’s capacity for heat removal. Have you ever wondered why an air conditioner’s capacity is measured in tons? If so, you’re not alone. A ton is hardly the unit of measurement that you’d expect in a relatively small-sized home appliance that moves air around.

Before modern cooling technology existed, people once cooled their homes and businesses by surrounding them with large blocks of ice. As this ice melted, it absorbed heat and created cooler temperatures indoors. Modern AC measurements come from this practice. It takes 286,000 BTUs to melt a single ton of ice. This number was divided by 24 (the number of hours in a day) to arrive at the BTU measurement for hourly cooling needs. Thus, a one-ton air conditioner can remove 12,000 BTUs of heat for every hour that it’s in operation. For every ton of AC capacity that’s added, another 12,000 BTUs of heat removal is provided. A two-ton air conditioner can remove 24,000 BTUs of heat hourly, and a three-ton air conditioner can remove 36,000 BTUs of heat.

HVAC companies take these measurements and apply them to building sizes, building layouts, ceiling heights, and all of the other factors that get considered when determining the best HVAC equipment for any environment.

Equipment Sizes vs. Physical Dimensions

In the context of heating and cooling capacity, HVAC unit sizes don’t actually refer to the physical dimensions of air conditioners or heaters. Instead, they refer to their heat removal or heat production abilities in terms of BTUs. Thus, choosing the right air conditioner or furnace size for your living environment isn’t as easy as looking at your current model and finding something comparable at your local home and hardware store. Working with a licensed HVAC professional and having a Manual J calculation performed is the surest way to get optimum value from your purchase. Getting the right cooling and heating capacity for both of these units will prolong their lifespans, ensure their efficiency, and help keep your energy bills under control.

Larger and More Powerful Doesn’t Mean Better

For homeowners with comfortable budgets, it’s often thought that the bigger a unit is, the better it will work. This is assumed to be true of both the physical dimensions of heating and cooling equipment and their capacity. In reality, too much power can wind up costing you a veritable fortune. A heater that’s too big for your home will warm your living environment up quickly. This will cause it to cycle on and then rapidly cycle back off, which wastes a lot of energy and expedites normal wear. Heaters that are too large for their intended service areas rarely make it to the ends of their expected lifespans.

The same problem occurs with oversize air conditioners. Overly large air conditioners constantly cycle off and on while providing powerful cooling in short bursts. They can also lead to indoor humidity issues. With ultra-fast cooling cycles, even though there are guaranteed to be lots of them, air conditioners never have the chance to extract excess moisture from the indoor air. This can eventually lead to moisture-related building damages and problems with mold.

Units That Are Smaller and Cheaper Can Cause Problems Too

Under-size heating and cooling equipment have to run all of the time. It’s simply not powerful enough to create and maintain the indoor temperatures that building residents want. Constantly running these units wears them down fast. Although you might save money upfront by purchasing a small, low-capacity unit, you’ll wind up having to replace it long before its time.

There are far better ways to save money on your HVAC unit than choosing your home heating and cooling equipment by yourself. Having a licensed HVAC technician determine the correct heating and cooling capacities for your home will allow you to get the most from these important appliances. With the right number of BTUs, your units will last longer, they’ll add more value to your property, and they’ll offer superior levels of performance and efficiency throughout their lifespans.

At Jerry Kelly Heating & Air Conditioning, we’ve been proudly serving residents of St. Peters, Missouri and the surrounding areas since 1977. We offer heater and air conditioner maintenance, installation, and repair services. We also provide zoned systems, water heaters, and indoor air quality control. If you need help finding the right HVAC equipment for your home, give Jerry Kelly Heating & Air Conditioning a call.

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