How to Determine the Right Size for My HVAC?

When installing an HVAC unit at your home, it is important to get the size right. An HVAC unit that is too large for your home will result in higher upfront costs and larger energy bills down the road. On the flipside, an HVAC unit that is too small will lead to poor heating and cooling, causing inconvenience and discomfort year-round. This is why you must carefully consider the size of your HVAC system when choosing one. You should also consult one of our Greenville HVAC experts.

Here’s a look at some important factors you should consider in this regard. With these factors in mind, you have a far better chance of choosing an HVAC unit that delivers the right amount of heating or cooling.


The insulation of your home factors into the expected load your HVAC is required to bear. Poor insulation forces an HVAC unit to exert more to achieve heating and cooling. In contrast, good insulation can trim down the load on the system. Depending on the type of insulation your home has, you may want to choose an HVAC system that can muster good heating and cooling.

Exterior Environment

The local climate, typical weather conditions and the landscape around your home also determine the load of your HVAC unit. If the landscape has green shrubbery, plants and trees, these can significantly cool the indoor environment, diminishing the HVAC load in the summers. Similarly, if your home’s windows are located so as to directly receive sunlight in the summers, this can also have an impact on HVAC heating during the winters.

Home Size

The size of your home is a major determinant in the size of HVAC unit that you need. The larger your home is, the more is the amount of space that needs heating and cooling. Consequently, larger homes require larger HVAC units. You can chart an estimate by calculating the square footage of all the rooms and the hallway at your home. Then add these to get an estimate of the overall square footage.

Typically, you will need 25 BTUs of energy to cool one square foot. You can multiply this number with the square footage you have calculated to get your energy needs in terms of BTUs. The next step is to get an HVAC with the required BTUs.

Windows and Ceilings

The number, type and placement of windows at your home also have an impact on your HVAC needs. More windows mean more sunlight and heat trickling into your home. If the windows directly face rising or setting sun, this only increase the amount of heat they let in. Similarly, single-pane windows let in more heat compared to double-pane windows which offer better insulation.

Ceilings are another important consideration in this regard. The BTU calculation method noted above is suitable for homes with ceilings up to 8 feet high. If your home has ceilings which are higher than 8 feet, you will need to add 25% to the calculated BTUs to get your figure right. This is because spaces with higher ceilings require a greater amount of cooling.

Other Variables

A number of other variables also need to be considered when determining the right size for your HVAC unit. These include factors like the age of your home, ventilation, electrical system efficiency and more. The age of the home is directly related to the structure’s energy efficiency. Typically, older homes will have poorer energy efficiency compared to the better insulated and designed modern homes.

Similarly, the quality of the electrical system directly impacts your HVAC unit’s performance. An HVAC system that works fine on a well-functioning electrical system may fall short of its performance when running on a poorly wired electrical system. This is why it is important to get an in-depth stock of your home’s electrical system, insulation, ventilation, structure and other aspects.

Hiring Greenville Heating and Air Experts

If you live in Greenville and want professional opinion on the type and size of HVAC system that is best for your home, we can help you. When helping homeowners make this choice, we strive to ensure that you choose a unit that is energy-efficient, cost-effective and suits your needs right.

Here at General Air, we also handle other aspects of HVAC installation, repairs and replacement. Whether you are considering adding a new HVAC unit, want to replace an old one, require routine maintenance or service, or simply need repairs, we have got you covered. Contact us today to hire our services or consult our experts for HVAC advice.

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