What to Know When Adding Central Air to an Older House

When you own an older home, adding central air may sound like a daydream. Many homeowners mistakenly believe a central air conditioning system isn’t affordable or practical. However, central air conditioning units are long-lasting so they’re worth the investment and they often take only a couple days to install in an older home.

Duct System Options

One concern when it comes to installing an air conditioner in an older home is the duct system. In the past, ductwork could be expensive and intrusive. However, with a mini-duct approach, the high-velocity system reduces the need for large ducts that take up most of your closet space. Instead, the system uses smaller tubing installed within the walls. There is typically little to no interior remodeling required with this type of install.

Ductless air conditioners are another option for older homes and involve the installation of a mini-split system. With this setup, a unit is mounted outside while another unit is mounted inside the home’s wall. Multiple units can be paired with a single outdoor unit for whole house cooling.

If you already have ductwork because of a furnace, installing a new central air system will be less intrusive. However, existing ductwork should be inspected first to guarantee it could handle the air volume from the new a/c unit. The ductwork may need to be sealed to increase efficiency as well.

Electrical Systems

The biggest hurdle many homeowners face when installing new air conditioning systems is making sure their current electrical system can handle running the unit. Older homes may still have 110 volt and 60-amp service. An electrician may need to be contacted to upgrade your service to 230-volt and 100-amp service to handle the air conditioner’s horse power.

Another upgrade you may need to make before installing central air is to put in a larger furnace blower. With a blower that’s too small, the coils are likely to freeze since the blower won’t be able to adequately blow air through the system.

Selecting an A/C Unit

Getting the cooling load calculations done for an older home is a crucial step in choosing a central air conditioning unit. By taking into consideration factors such as home size, insulation amounts, and window and door placement, a contractor can recommend the size unit required to overcome the amount of heat found in the home. Keep in mind bigger units don’t always work better. If your unit is too large, you may find it difficult to regulate the humidity levels in the home.

Along with the size, the efficiency rating should be considered. Although a lower rated system has a reduced startup cost, energy bills will cost more over the lifetime of the unit.


Customers located in the Raleigh, NC area can contact Delta Heating & Cooling for assistance with all of their heating and air conditioning needs. The family-owned company is experts in HVAC installation and maintenance. Contact them today at (919) 256-5120 for more information