Have you asked yourself, “What size HVAC unit do I need for my home?” Here’s how to choose the right unit for your house.
Your home’s heating, ventilation, and air conditioning system is essential to your happiness and good health. When you buy an HVAC system, you should know what size you need.
The system’s size determines how warm your home stays during winter and how cool it stays in summer. Your HVAC also filters and cleans the air in your home to keep you and your family healthy.
With the HVAC industry predicted to grow 4.6 percent up to 2024, the market is filled with many models and a range of sizes. That makes it even harder to make the best choice.
Here’s a guide to factors you should consider.
Before you worry about size calculations, it’s important to understand how your HVAC system works.
The ventilation function provides fresh air in the home. In the past, most houses relied on natural ventilation through windows, vents and doors. But construction advances now seal houses more tightly.
This creates the need for mechanical ventilation through the HVAC system. Once air enters, it’s:
- Drawn into the air handling unit
- Dust, allergens and other particles removed
- Sent for either heating or cooling
- Released into your home
Central HVAC systems circulate the air through a network of ducts and registers inside the house.
Other systems, like portable heaters or window air conditioners, directly feed air into the specific room or space they occupy.
Calculate the Size You Need
Why’s it so important to get the size of your HVAC system right? If it’s too big, you waste money and energy. If too small, it won’t heat, cool and ventilate the way you need.
The best way to determine the size is to calculate your energy requirements. Here are various factors to consider.
How many units of heating and tons of AC do you need?
One way to determine the size needed is to have a Manual J calculation of your house done. The calculation gives you precise measurements because it considers a wide range of factors. These include:
- The climate zones
- Square footage
- Type and size of duct work
- Amount of insulation
- Number of windows and their styles
- Appliances radiate heat
- Natural shade and light
- Number of people who use the system
The Manual J calculation is a tool recommended by the Air Conditioning Contractors of America (ACCA). The tool helps them determine how much heat is gained or lost in warm and cold months. It helps contractors design HVAC systems in their proportionate sizes.
Many utility companies will do the calculation for you for free. Or you can have an energy auditor do it for you.
Square foot measurements
You can roughly estimate the size of the HVAC system needed through your house’s square footage. It might be written down somewhere or you may have to measure it yourself.
Measure the lengths and widths of each room with a tape measure. Multiply the figures to get its square footage. For example, a room 9 feet wide by 14 feet long (9 x 14 sq. ft.) is 126 total square feet.
Do this mathematical equation for each room and hallway. include bathrooms and closets. Add the figures to get the square footage of your house.
Calculate British Thermal Units (BTU)
BTU is the unit used to measure your energy consumption for heating and cooling. Each square foot in your home consumes about 25 BTUs. So to get the number of units you need for your home, multiply the total square feet of your house with 25. This gives your base BTU measurement.
When you calculate BTU, account for high ceilings. If a room’s ceiling is more than 8 feet tall, add 25% to the total square feet for that room.
Once you have the BTU requirements, there are only two simple calculations left to do:
- For air conditioning, divide the BTU by 12,000 to get the tonnage
- For heating component, divide the BTU by the unit’s posted efficiency
You’ll come across many HVAC models with varying capacities. Talk to an HVAC dealer to get more product details . If you lack the correct BTU sizes, the dealer can help you do the calculations.
Another challenge may come if you can’t find the right size per your calculations. For example, your BTU might be 25,000, but the available units are 24,000 or 28,000. Go for the larger system.
A little more power won’t hurt you. It also assures you’re covered when it’s extremely hot or cold. The smaller unit may not meet your needs on such days.
But avoid a massive unit because it will heat or cool your home too quickly and shut off. This leads to uneven cycles and temperatures, not to mention higher power bills.
The heating, ventilation and air conditioning system you select does more than just heat or cool your home. It improves the air you and your family breathe. It assures their physical comfort.
Remember, you want to make the best choice. Have an expert guide you. Getting it wrong will be costly in the long run.
If you have questions, please call us at (402) 731-2727. We’re always at your service!