One of the most important issues when buying a new HVAC system is sizing. The wrong size can cause all sorts of problems, costing you a lot of money. What happens if it’s too big or too small? Here’s how to know what HVAC size your home needs.

Manual J

For your AC, 1 ton of cooling will cover 600 square feet of your home, on average. It’s the same for your gas furnace. You should know that 600 square feet requires approximately 12,000 BTUs, which is equal to 1 ton of heat. Therefore, an 1,800-square-foot home should require a system with a 3-ton capacity.

However, there are other factors that can affect your sizing needs as well. Large windows, particularly facing south, let in sunlight, which can heat your home. The amount of insulation you have can also affect how much power it takes to bring your home to temperature. Even your ceiling height can be a factor in HVAC size.

This is why it’s essential that your HVAC contractor use Manual J when sizing your system. It provides a guideline that lets them take all the factors of your home into consideration and find the correct-size system to heat or cool it efficiently.

The Wrong HVAC Size

What happens if your contractor doesn’t use Manual J and you end up with the wrong-size system in your home? If it’s too small, there won’t be enough power to heat or cool the area effectively. The unit will run constantly, trying to get your home to the proper temperature. Your house will be uncomfortable while your system wastes energy and ultimately wears out prematurely.

On the other hand, if the unit is too big, it causes short cycling. The system turns on and off repeatedly, in rapid succession. This also wastes energy and wears out your system, as well as causing hot and cold spots throughout your home and making things generally clammy and uncomfortable.

To ensure you get the right HVAC size for your home, contact us at Mowery Heating, Cooling and Plumbing. We keep Indianapolis homes comfortable and efficient.