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Cool Touch Air Conditioning and Heating Blog

Should Two Level Homes Have More Than One A/C Unit?

It can be challenging to maintain a comfortable temperature in an older two-level home with only one central air-conditioning unit. Using two systems has many advantages over a single unit, but it is not always the best choice. The age and design of your house may affect your decision, along with the costs of purchasing and running a second central air-conditioning unit.

Costs to Consider

Purchasing two central air-conditioning units can be more expensive initially than purchasing a single unit, but the cost difference may not be as much as you think. You need either two smaller units or one larger unit to run the entire house. The added cost of the second unit may be offset by the energy savings. Much depends on your house and how you use the air conditioner.

Balancing Your Home’s Temperature

In many older homes, it is difficult to keep the entire house at the same temperature. The second floor is often much warmer than the first, so one area of the house often seems too hot or two cold. Using separate central air-conditioning units for each floor allows you to maintain a comfortable temperature throughout the entire house.

Saving Household Energy

A single non-zoned central air-conditioning unit requires you to keep all areas cool, even when some are not in use. In many homes, the first floor can be cooled during the daytime and turned off at night, while the upstairs bedrooms may only need to be cooled at night. In this situation, separate central air-conditioning units can result in significant energy savings. This situation can also be solved with a zoned air-conditioning unit.

Cooling System Failure

If one of the central air-conditioning units goes out, you may be able to keep the house cool enough with the other unit until repairs are made, though this is only important in areas where summer temperatures are extreme. Having two units also doubles the chance of system failure and increases the cost of repairs overall.

Advantages of a Household Zoning System

It is possible to install a single central air-conditioning unit, with two or more thermostats, that can cool the house equally. A zoned system includes dampers within the ductwork that open and close to regulate the flow of air and temperature in each zone. A regular central air-conditioning system, by contrast, pushes cool air to all parts of the house. A single zoned system has many of the advantages of a two-unit system: The house is divided into two or more zones — in this case, upstairs and downstairs. Each zone of the house can be turned down or closed off to save energy. The thermostat in each zone controls the temperature in the zone. A zoned system costs more to install than a regular single air-conditioning unit, but the energy savings may make up the difference over time.

If you have any questions regarding your current cooling system, how to program your thermostat, or if it’s time for a new A/C unit, please give us a call. One of our experienced technicians would be happy to answer your questions and explain the options that might best suit your family’s needs. Please visit

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