Practical Advice for Installing an Air Conditioner

It’s hot all across the U.S. Here in Dallas, Texas, we already hit 100 degrees, and morning lows barely crack the 80s. Temps won’t let up until late September— if we’re lucky. In this heat, an air conditioner is a necessity. I had window units for 20 years, but for ease, efficiency and quiet operation, nothing beats central air. My central AC is about 20 years old, which is close to the upper limit, so I’ve been thinking about investing in a new system.

I’m an electrician, but even experienced tradespeople like myself need help installing central heating, ventilation and air conditioning (HVAC) equipment. So, I decided to ask some experts. This isn’t a DIY job, but it’s important to know what you’re getting into. Ahead, two HVAC techs give practical advice for installing a central air conditioner.

Choose the Right Air Conditioner

Central air conditioning has two main types: a split system, which is the most common, and a package system. A split system has two main parts. “The condensing unit goes outside, and the air handler or furnace goes inside,” says Micah Sherman, a virtual HVAC technician with Frontdoor. Package systems contain everything in one cabinet, usually placed outside on a slab next to the house or on the roof.

Split systems require more room inside for the air handler, but they’re more efficient than package systems. And because the outside portion is smaller, placement around your house is more flexible. Package systems are easier to install and service due to their self-contained parts (you never have to let a technician into your home), but they can be noisier than splits because all the loud components are housed together.

Consider Energy Efficiency

Air conditioners are one of the biggest energy hogs in your home. When shopping, look for the SEER rating, which stands for Seasonal Energy Efficiency Rating, to keep your energy footprint and your utility bills to a minimum. “The SEER rating indicates the total cooling capacity over the amount of energy used in the same period of time,” says Jay Kline, operations manager at Penguin Air, Plumbing & Electrical in Phoenix, Arizona.

“The higher the SEER rating, the more efficient the system is,” Sherman adds. The U.S. Department of Energy sets minimum SEER standards, which are different for northern and southern states. “In warmer regions, having a higher SEER-rated system can be more beneficial where you run AC most of the year,” Sherman says. “In cooler climates, there may not be as much value in higher SEER systems.”

Size It Right

With residential central air conditioning systems, bigger is not always better. “A unit that is too large can cool the home too quickly, which can lead to poor humidity control and discomfort,” Sherman says. “A system that is too small can struggle to keep up with the heat load and result in high energy costs and premature system failure.” To get one just right, Sherman says you have to do a load calculation.

Contractors use what’s called a “Manual J” calculation to size HVAC systems, based on a home’s square footage and other factors, such as the climate, insulation type, number and placement of windows and doors, and the number of occupants. This calculation will tell you the number of British Thermal Units (BTU) needed to cool your home effectively. It’s best to leave these calculations to the pros.

Inspect the Ductwork

Sizing the air conditioner itself is only half the story. Your ducts have an optimal size, too. If they’re too small, static pressure builds up in the ducts, overworking the unit and making a bunch of noise as air moves through. Oversized ductwork, on the other hand, is inefficient at moving air, so far-away rooms won’t get as much air as they should.

Luckily, as long as they’re sized correctly, ducts can usually stay— “Unless the existing ductwork is damaged,” Sherman says. “You may need to build a new transition duct to attach the new system to the ductwork, but that’s fairly simple.”

Choose the Right Spot

Your HVAC contractor will pick the ideal placement for the outside condenser unit based on system design, building codes and safety considerations. In general, you want a spot that won’t get washed out by water or baked nonstop by the sun. Kline recommends placing the condenser on the north side of a home because it gets the least direct sunlight, so it stays cooler.

Don’t try to hide your air conditioner behind bushes, plants or too-close fences. First, it’ll make your AC work harder. “A central air conditioner should have two to three feet of clearance on each side, as obstructions can prevent the system from adequately cooling,” Kline says. Leaving space around the unit will also allow service technicians to access it.

Maintain Your Air Conditioner

“Maintenance should be performed at least once a year, preferably twice, once before the major heating and cooling seasons,” Sherman says. Routine jobs like changing filters can be tackled yourself. Brush off leaves and branches, change your air filters and look for issues like higher-than-usual energy bills and loud noises.

Sherman says filter changes every three months are adequate, but you should check them monthly and switch to more frequent changes if needed. If you need help, call a pro. “Many repairs and maintenance tasks can be done by homeowners themselves, with the help and guidance of an expert,” the virtual HVAC technician says.

About the Experts

• Micah Sherman is a virtual HVAC technician for Frontdoor, an app service that connects homeowners with technicians so they can feel empowered to do their own repairs.
• Jay Kline is an HVAC technician who grew up working for his family’s heating and air conditioning company. Kline now works for Penguin Air, Plumbing & Electrical, which serves the greater Phoenix area.