Knowing how to choose the right size HVAC system can be difficult. A system that’s too big will boost your energy bills and environmental footprint, while a system that’s too small will always be playing catch-up. There are a few different steps to determining the right size and selecting the perfect system.
HVAC services in Richmond Hill by Georgia Air Cooling & Heating will help you save money and achieve consistent home comfort. At Georgia Air Cooling & Heating, our experts have years of experience helping customers determine the best size HVAC system for their home. We calculate your energy requirements then help you select an energy-efficient model.
Many people ask how to choose the right size HVAC system. We detail the steps to determine your size needs and provide other essential information.
Understanding HVAC Components
Your HVAC system consists of a heating, ventilation, and air conditioning unit. Together, these units help achieve the proper indoor temperature. Your ventilation system prevents air from getting stale or spreading contaminations throughout the home.
You’ll need to understand how your central air conditioning system and different types of heating systems operate to determine your energy needs and more.
Air Conditioning Systems
Your air conditioning system’s main components include the fan, compressor unit, and refrigerant lines. Air conditioners intake warm air from indoors, compress condensation to release heat, and cool the air before it exits the air ducts again. This process continues until your home reaches the set temperature.
HVAC professionals measure air conditioners’ energy output in British Thermal Units (BTUs). It takes around 25 BTUs to cool a square foot of space. Knowing this, you can calculate your home’s cooling requirements.
Heating systems require fuel or electricity to operate. Their energy output is also a calculation of BTUs. Depending on the type of heating system you have and how big your house is, you may have BTU requirements of up to 200,000 BTU or more.
A furnace relies on gas or electricity to run. Gas burners warm the heat exchanger. As cool air passes through, the heat transfers to the air then gets blown out of the ventilation system.
Electric furnaces work essentially the same as gas furnaces, and the only difference is the type of power necessary to operate. A furnace can be highly efficient depending on its SEER rating.
Homeowners can save significantly on utility bills by getting a heat pump. A heat pump combines heating and cooling components into one unit. Heat pumps rely on electricity and transfer hot or cold air from indoors to outside the home.
Determine Your Heating and AC Needs
The next step regarding how to choose the right size HVAC system is to calculate your energy needs for heating and cooling. You can either use a Manual J calculation or measure the square footage of your home to calculate the necessary BTUs.
Commercial spaces feature HVAC systems with different designs. Be mindful that residential HVAC systems require different calculations than commercial HVAC systems due to their placement and other factors.
Manual J Calculation
The Manual J calculation, or HVAC load calculation, is a detailed calculation that determines how much heating and cooling your space needs during the appropriate time of year. Manual J is a standard protocol that all HVAC companies can use. This precise measurement considers several factors when determining your space’s energy needs.
Your HVAC technician will consider:
- The climate you live in
- Your home’s square footage
- The amount of insulation your home has
- The style and amount of windows in your home
- Whether the home has direct sunlight exposure
- How many people are in the household
- The condition of your air ducts
Your local HVAC contractor, like Georgia Air, can perform a Manual J calculation. You’ll get an exact number for how many BTUs are necessary for the successful cooling and heating of your home.
Measuring Square Footage
An alternative method regarding how to choose the right size HVAC system is by calculating square footage. If you want to calculate your home’s energy load yourself, you can get a rough estimate if you know how many square feet it has.
You’ll need to know the BTUs necessary for heating and cooling systems. Your home’s condition and the climate you live in will directly affect these calculations.
It takes around 25 BTUs to cool one square foot of your space. To get a rough estimate, multiply your home’s square footage by 25 BTUs.
A home with only 500 square feet will need around 12,000 BTUs. From there, you’ll need to consider different factors that may contribute to higher energy loads. High-volume rooms, rooms that produce extra heat, and rooms with notable shade or sun exposure will affect your needs.
Rooms with significant traffic compared to other places in the house may need an additional 500 BTU to make up for the energy increase. Kitchens add 4,000 BTUs to this number. Rooms with sun or shade exposure will either increase or decrease a room’s BTUs by 10%.
While cooling needs have straightforward calculations, calculating the heat load is slightly more complex. Your home’s condition and where you live determine the BTUs per square foot or the heating factor. After determining the heating factor, you can make calculations based on square footage.
A home’s age, the amount of insulation, and the climate determine how efficient the space is at retaining heat. Typically, older homes need more BTUs than new homes. Similarly, your energy load goes up more in cold climates, while you need fewer BTUs to heat a home in a warm environment.
Four different combinations between the home type and climate will determine your heating factor:
- New home in a warm climate: 30 BTUs
- Old house in a warm climate: 35 BTUs
- New house in a cold climate: 50 BTUs
- Old home in a cold climate: 60 BTUs
Considering Georgia’s climate, you’ll either result with a heating factor of 30 or 35 BTUs.
From there, you’ll multiply the appropriate heating factor in BTUs with the number of square footage your home has. Efficiency inconsistencies in furnaces can also change this number. Divide your newly calculated BTUs by 0.8 to make up for the 80% efficiency.
The final result will be two numbers: one for your cooling needs and one for heating needs.
Select an HVAC Unit
Next, it’s time to choose an HVAC system that works for your lifestyle and meets your energy requirements. You can choose from separate air conditioners and heating systems or get an all-in-one solution, like a heat pump. Working with a trusted HVAC contractor will ensure the best results.
Many HVAC contractors also sell HVAC system brands that they service. Contractors offer a wide selection of HVAC units covering different BTU requirements. Even if your dealer doesn’t have the right size, you can still get good results.
Units That Are Too Big
In some cases, your HVAC dealer may only have a slightly more powerful unit than your requirements. While it’s typically not a good idea to purchase a unit that is too big for your home, some situations warrant it.
You should only purchase a unit that is too big for your BTU needs if it is only a few thousand BTUs bigger. If your HVAC dealer only has options slightly lower and higher than your BTU requirements, choosing the bigger unit will ensure you stay comfortable.
A slightly more powerful HVAC system isn’t always detrimental. Considering Georgia’s harsh weather, the extra power will ensure your system can handle such extreme temperatures. If your unit is significantly too large, you’ll notice as the system short cycles and your energy bill skyrockets.
Typically, the BTUs should not exceed 25% of your final energy load calculation for heat pumps, 15% of your measurement for cooling, and 40% for heating.
Units That Are Too Small
It’s not wise to choose a unit that is slightly too small for your HVAC energy needs. Without enough power, your HVAC system will constantly run as it tries to keep up with temperature demands, and your energy bill will increase significantly.
If your system doesn’t have enough power, your home will remain chilly on cold days and struggle to cool down during Georgia’s hot summers.
Get an Accurate HVAC Sizing and Installation Today
Whether you need to determine your energy load or need assistance selecting the proper size air conditioner, the team at Georgia Air Cooling & Heating is here. Our team has the necessary training, education, and experience to determine your home’s energy needs and help you select the perfect air conditioning system, furnace, or another HVAC option.
If you’re still wondering how to choose the right size HVAC system, our knowledgeable team can help. We offer various high-quality HVAC services and can help you learn more about air conditioning repair, replacement, and our other services. Contact Georgia Air Cooling & Heating in Richmond Hill, GA, today at 912.513.3756.