If you're installing a new air conditioning system in your home, you typically have three choices: window units, central air systems, and mini-split systems. However, if you're looking to upgrade from window units, you'll need to choose between a traditional central system and a ductless mini-split. Both options have advantages, but mini-split systems may be a more efficient choice for some homes.
What Determines Efficiency?
When it comes to air conditioning systems, efficiency can be both a simple and complex topic. On the simple end of things, you can look at SEER ratings to make an apples-to-apples comparison between two air conditioning units. Like AFUE ratings for furnaces, the SEER rating of an air conditioner provides a ratio of cooling power to energy usage. Units with higher SEER ratings are more energy efficient.
This simple picture would be sufficient if you only cared about the cooling power at the evaporator coils, but the real world is more complex. In your home, the evaporator coils dry and cool air inside the air handling unit. Your blower motor must then deliver this cool air throughout your home via ductwork to reduce the structure's overall interior temperature.
When viewed this way, the efficiency question can become more complex. How well insulated is your home's ductwork? How old is it? How much cool air are you losing between the air handler unit and the vents? According to the EPA, ductwork may account for efficiency losses as high as 30% in a typical residential air conditioning system.
Are Mini-Split Systems More Efficient?
Mini-split and central air conditioning systems use the same general design: an exterior condenser unit connected via refrigerant plumbing to an interior air handler and evaporator. Unlike centralized systems, mini-splits combine the evaporator and blower into a "head" unit that directly cools one or more rooms. As a result, these systems don't suffer from efficiency losses due to ductwork.
If your goal is to build the most efficient system possible, mini-splits are often a better choice. However, other factors may come into play for your specific home. For example, mini-splits tend to cost more upfront than central air systems. This added cost may offset the potential efficiency gains for homes with existing ductwork from a previous air conditioning install or forced-air heating.
You may also see fewer efficiency gains if the ductwork in your home is relatively new or if you've recently taken steps to add insulation and repair leaks. Although some loss is unavoidable, you can take steps to minimize these problems and increase the overall efficiency of a central air system. Along with the lower installation cost, these factors might swing the financial advantage away from mini-split units.
Ultimately, the needs of every home and family are unique. Mini-split systems are worth considering if you're looking for a way to maximize efficiency with your new air conditioner, but always discuss your choices with a qualified HVAC installer before making any final decisions. Contact a company like Pacific Air & Heating to learn more.