Is your second-floor sweltering while the basement is sub-zero temperatures? Are some rooms drafty while others are stale? It could be that you got the wrong size unit during your HVAC installation.
Your heating and cooling system is critical in keeping your home and your family comfortable. To get those most out of your furnace and air conditioner, it needs to be the correct size for your home.
A unit too big can cause temperature swings and waste energy while a unit that is too small will not be able to sufficiently heat or cool your home. Choosing the right size furnace for your home is crucial to it performing properly and efficiently.
How to Calculate the Perfect Size HVAC System
In order to determine the perfect size of air conditioning or furnace unit for your home, you must understand how much power you need and how it is measured.
Air Conditioner Sizing: An air conditioner size is measured in tons. In the appliance world, tons doesn’t refer to weight, but rather to its cooling ability. A 2-ton unit can generate more cooling in an hour than a 1-ton unit. Consequently, a larger unit also uses more energy and creates higher energy bills than a smaller unit.
Typically, most homes have an air conditioner in the range of 1-ton to 5-ton. An air conditioner over 5-ton is a commercial unit that is surplus to the requirements of most homes.
In order to choose the system that meets your needs, you must calculate how much power it takes to heat and cool your home
Measuring Power: Power from the central air system is measured in BTUs. A BTU, or British Thermal Unit, is used to measure the amount of heat required to raise 1 pound of water 1-degree Fahrenheit. More BTUs means a more powerful appliance. There are two methods that calculate the BTUs your home needs to stay comfortable
- Method 1: Manual J Calculation
According to most experts, this is the most accurate way to calculate the amount of BTUs your home needs. The Manual J method measures the total amount of heat lost through the home during the winter. This number is compared to the total amount of heat gained in the home during the summer. These numbers are calculated by considering square footage, climate, ductwork, windows, sunlight, insulation, other appliances, etc. There are some online calculators that can create an estimate, but is best to be corroborated by a professional contractor.
- Method 2: Climate Method
This method is based purely on the climate where you live. The hotter climate you live in, the more cooling power per square foot of area your HVAC system needs to have. Each climate is assigned a BTU range based on regional averages:
- Zones 1 & 2 (hot): 22-30 Btu/sq. Ft.
- Zone 3 (warm): 20-24 Btu/sq. Ft.
- Zone 4 (moderate): 18-22 Btu/sq. Ft.
- Zone 5 (cool): 16-20 Btu/sq. Ft.
- Zone 6 (cold): 14-18 Btu/sq. Ft.
- Zone 7 (very cold): 12-16 Btu/sq. Ft.
The BTU range is multiplied by the square footage of your home. For example, if you have a 2,000 square foot home in Houston, Texas the calculation would be as follows:
Zones 1 & 2 (hot): 2,000 x 22-30 = 44,000 to 60,000 BTU. This means you need a 4.0 – 5.0 ton system.
On the flip side, if you live in Minot, North Dakota, the calculation would be:
Zone 7 (very cold): 2,000 x 12-16 = a 24,000 to 32,000 BTU. This means you need a 2.0 – 2.5 ton system.
These numbers can fluctuate based on your home’s construction and making the calculation can be a little daunting. To simplify, a home in a cooler climate needs a smaller air conditioner and a larger heat furnace and a home in a hot climate needs a larger air conditioner and a small heat furnace.
What’s the Best Efficiency Air Conditioner for My Home?
Depending on what climate you live in, you need an HVAC system to keep up with demand. Different homes in different climates need different efficiencies. HVAC system efficiency is rated using the SEER rating system.
The SEER is the Seasonal Energy Efficiency Ratio. The higher the SEER, the more efficient the unit is. For example, if you upgrade a 16 SEER rated unit to a 20 SEER rated unit, the homeowner will see roughly 20% more energy efficiency from their HVAC system. Energy Star rated ranges are between 12 and 23 SEER.
Based on the climate zone you live in from the chart above, here are the SEER ratings that are best suited for you.
- Zones 1 & 2 (hot): 18 SEER and up
- Zone 3 (very warm): 17-18 SEER
- Zone 4 (warm): 16-18 SEER
- Zone 5 (moderate): 15-16 SEER
- Zone 6 (cool): 15-16 SEER
- Zone 7 (cool): Up to 15 SEER
Moist air is harder to cool, so if you live in an area with high humidity, then getting a more efficient system is critical to reducing energy costs and making your home more comfortable. The SEER rating coincides with the BTU range. Lower SEER-rated systems have a lower BTU and vice versa.
Factors to Consider When Choosing the Right Unit Size
Selecting that perfect furnace and AC unit is not a clear cut, dry answer. It’s not just about plugging in numbers. Many factors play into the decision and it’s helpful to know why some units work better in different homes.
- The age of the home: If you live in an older home, it will be less energy efficient than newer homes. Older homes simply do not hold heat or air conditioning as well as today’s newer homes, because they were built differently. If you’re installing a new unit in an older home, it’s important to check to see if the electrical and existing ductwork components can handle the upgrade.
- Exterior walls and windows: The size, volume, and condition of the walls and windows in your home can make a big difference into how well your HVAC system works. If your windows let a lot of sunlight through, then your heater does not have to work as hard to heat your home, while the AC unit has to work harder than necessary.
- Weatherproofing and insulation: Sealed doors and windows along with added insulation can help your HVAC system maintain heat and cool air better. This helps your home maintain a more controlled climate and keeps your energy bills down.
Hire the Right Expert
Even if you purchase a top-of-the-line heating and air conditioning system, it can not perform at its best without proper installation. A lousy installation job can almost immediately waste your investment. Instead, look for a professional who can do the job right the first time. Ensure they have a valid license, credentials, knowledge, and experience in the field. They should also have the necessary insurance to protect you and your home. Lastly, ask for their certifications direct from HVAC manufacturers, to ensure they’re trained to install your specific product.
At Hassle Free HVAC, we have made sure each of our installers meets our high standards and expectations, so you get the best HVAC installation in the industry.
Ready to Make A Decision
The thought of a new HVAC installation can make even the strongest stomach drop to the floor. It’s a critical component to the home and represents a significant investment.
A system that’s too large wastes energy warming up and cooling down over and over as it continuously cycles off and on. A too-large furnace often requires unnecessarily large ductwork, which can also compromise energy savings.
A properly sized system is designed as closely as possible to the needs of the house and should run almost continuously without sacrificing efficiency. Knowing how to select the ideal size for your home can save you time, money, and prevent a bad headache. So work with the experts at Hassle Free for your next HVAC installation.