Residential Plumbing & HVAC Experts

Find Out Why You Should Buy an HVAC System, Not Just a Replacement Unit

If your central HVAC system quits working, it’s most likely due to a failure of either the outdoor compressor or indoor evaporator, but not both. Before you decide to save money by replacing the failed component instead of buying a whole system, it’s important to consider the following factors.

Energy Efficiency

The efficiency ratings for new central HVAC systems are based on two matched components that work in tandem. Your HVAC system might function if you replace only one component, but its overall efficiency will be limited by the remaining older unit, so you won’t gain the improvement in efficiency you can expect from a complete new system.


The efficiency incompatibility between old and new components in a mismatched HVAC system puts extra strain on the older unit, and this erodes its reliability. The additional strain increases the risk that the aging component will fail at the peak of the season, which could leave you facing an inconvenient equipment replacement at the worst possible time.

Operating Costs

If you invest in a whole system, you’ll benefit from energy savings and lower operating costs for maintenance and repairs over its service life. Replacing just one component robs you of these potential savings, and you’ll still have the expense of replacing the other half of the system in the near future.

Advanced Features

Upgrading your entire HVAC system gives you the chance to shop for the latest equipment features and design advancements. By having a complete new system installed, you can choose features and options that improve comfort, humidity control, and performance, such as more efficient coil designs, electronically commutated motors (ECM), scroll compressors, thermal expansion valves, and zoning.

Equipment Warranty

HVAC manufacturers only warrant split-system components that are installed together according to their strict specifications. Having a new component added to your older system makes it impossible to meet these specs, so it voids the coverage you’d normally have against failures caused by manufacturer defects.

To learn more about why it’s better to buy a completely new HVAC system for your San Diego-area home, contact us at Sherlock Plumbing, Heating & Air.