If you’re shopping for a new air conditioner, you may come across the initials BTU. It stands for British Thermal Unit and is essential for determining the capacity of your air conditioner. While it is known mainly by HVAC professionals, you can learn more about your AC by understanding it. Here is an outline of the definition of BTU and its implications for AC sizing and installation.

What Is a BTU in Air Conditioning?

The British Thermal Unit is the international unit for measuring the heat energy in a system. It can be quantified as the amount of energy needed to heat one pound of water by one degree Fahrenheit. The measurements are taken at one atmospheric unit of pressure.

In the HVAC industry, it is usually in the form of BTU per hour — that is, the British Thermal Units it would take to heat a room in an hour. One BTU/hour is equivalent to 0.2931 watts. The higher the BTU, the more the weight and cost of the unit.

Because the BTU measures heat in terms of pounds of water, it is also valuable for gauging heat energy in water systems. In the case of HVAC, it records the amount of hot air the system removes from the interior. Air conditioning systems eject hot air from the interior, then circulate cool air back.

BTUs and Sizing Considerations for Your AC

The British Thermal Unit is a unit of measurement for sizing your air conditioner. Sizing does not refer to the dimensions of your equipment. It indicates the ideal capacity of the system in BTUs that can supply cool air to your home with efficiency.

To determine the correct sizing, professionals will often consider the square footage of your home. The rule of thumb is that you need 20 to 30 BTUs per square foot. For small rooms of about 300-square feet, you may need between 6,000 and 9000 BTUs.

However, those figures are rough estimates. The process of sizing has to incorporate other factors into your calculations. For example, rooms with high ceilings will need an AC with a larger capacity than a room with a regular roof. Some spaces, such as the kitchen, may have greater energy demand due to the ambient heat from appliances.

Besides the orientation and square footage of space, the installation technician has to consider climatic factors. Canada has seven climatic zones, ranging from regions with mild summer weather to chilly, cold winters.

The province of Nova Scotia is often subject to temperature fluctuations. Your AC should have adequate power to regulate extreme heat and cold. A professional assessment is critical before you can determine the capacity of your cooling system. You can talk to Shines Energy‘s certified technicians for AC installation solutions in Dartmouth.

Other Factors to Consider When Sizing

Open-concept floor plans have a higher demand for cooling because they have fewer walls to contain cool air. Leakages within the building’s cavity will allow conditioned air to escape through doors, windows, and crawlspaces.

The heating requirements will also depend on whether the home has one or multiple floors. A building with two floors will usually have lower energy demands. That is because the floor acts as an insulation that prevents heat gain within the building.

Another factor that will impact the energy requirements is the grade of insulation. The insulation has to match the demands of your climatic zone. Dartmouth is in climate zone 6, and the value for an above-grade wall is R-17.

The R-value indicates the ability of the material to resist heat. The higher the value, the more energy efficient it will be for the building. Additionally, different parts of the house will have varying insulation requirements.

Why Sizing and the BTU Value Must Be Accurate

The correct sizing of your AC is not only for energy savings but also for the longevity of your equipment. A unit that has a lower BTU value than the requirements of the room will run continuously. The longer your air conditioner is cooling, the more energy it will consume. Components within the system are also more likely to break down.

You could opt for a much larger unit to ensure that your home is cozy in the summer. However, if the system’s capacity exceeds the requirements, it will cool too rapidly. As a result, the air conditioner will keep shutting off to prevent overcooling your home. An AC that cycles frequently is prone to malfunctions that can impact its durability.

An oversized air conditioning system will struggle to control humidity. That is because it does not run as often as a regular unit. As a result, the AC does not get the chance to remove moisture from the interior.

Features to Boost Your AC’s Cooling Capacity

Some features could also influence the efficiency of your air conditioner. Modern technology is supplementing the capacity of cooling appliances to regulate moisture and humidity. One such feature is a variable speed motor.

An AC with a variable speed motor can change its motor’s speed depending on the building’s cooling demands. Unlike conventional equipment, it can run at different capacities, rather than on and off.

The advantage of using a variable speed air conditioner is that it saves energy by running only when necessary. A variable-speed AC is more efficient at balancing the cooling and dehumidification needs of your home.

Another feature to consider for modern ACs is the condenser’s design. Condensers made of a single material can maintain their efficiency better than those made of different metals. Those components are more resistant to corrosive compounds and surroundings.

How BTU Is Related to Energy Efficiency Ratings

SEER (Seasonal Energy Efficiency Rating) is used to determine the efficiency of a cooling unit against climatic factors. The rating is the total cooling output divided by the total electrical input into the system. Therefore, it is the total number of BTUs divided by watt-hours.

The higher the ratio of BTUs to watts per hour, the more energy efficient it will be. An air conditioner with a SEER rating of 13 will consume approximately 30% more power than a SEER rating of 18. In Canada, the minimum rating is 13, and equipment with a 14.5 gets an Energy Star Certification.

An Energy Star label certifies that the appliance meets the efficiency standards set by regulators. Those appliances can use about 8% less energy than conventional models.

They often have large compressors with a greater capacity to regulate heat. Energy Star-certified equipment could have features such as a variable flow refrigerant or a variable-speed motor.

If your air conditioning unit is not adequately cooling your home, you may want to consider replacing it. But there could be external factors affecting the performance of your system. Your equipment may have no faults. Our certified professional will evaluate your home and walk you through the options that fit your lifestyle.

Shines Energy is a leading heating and cooling solutions provider in Dartmouth and its surroundings. Our team has the requisite skills to handle a wide range of air conditioning and heating issues. From ductless systems to heat pumps, our staff can deliver exceptional services. We have fair pricing and credit with flexible financing options. Contact our technicians in Dartmouth for prompt AC services today.

company icon