A frequent question arises in consulting a homeowner, which is “Do I need to replace my furnace as well?” The answer is often yes.
The minimum SEER, which stands for Seasonal Energy Efficiency Ratio, is now 14 for the Southeast United States. If the a/c is replaced, but not the furnace, only the minimum 14 SEER can be guaranteed. This is because you are matching two new components (the condensing unit and evaporator coil) with an older component (furnace or air handler), which contains the fan blower.
Replacing all three components allows the homeowner to upgrade total efficiency beyond that of 14 SEER. Higher end furnaces contain high-efficiency and/or variable speed fan blowers. These types of fans run in heating and cooling mode and help maintain lower humidity levels in the warm summer months.
Local for-profit electric providers can offer rebate incentives for upgrading HVAC systems. These usually apply when both the a/c and heating side of the system is replaced.
Lastly, if a homeowner is experiencing less-than-desired cooling, the air conditioner could be undersized. One must be wary in upsizing the a/c only, as the furnace fan blower could be undersized as well, and the increased capacity will be wasted.
In summary, several factors beyond simply the increased capital outlay should be considered in evaluating whether a full system changeout is the better approach.
Craig Sopo 