Can You Install An Air Conditioner With Your Current Furnace?

Posted on: 1 November 2016


If your home currently has forced air heating and you want air conditioning, the easiest solution is often to add a central air conditioner to your system. However, adding central air with an existing furnace does have its intricacies, and HVAC companies often prefer to replace the furnace and AC unit together. Simply adding an AC unit to your current furnace might be an option – depending on a few factors.

Do the ducts allow for it?

In older homes that were not designed with air conditioning in mind, the ductwork may not be sufficient to cool the home effectively. For instance, since hot air rises, ducts don't have to allow for too much heat traveling upstairs. However, the upstairs of the home gets really hot and requires a lot of cool air in the summer – so larger ducts and more vents will be needed upstairs to get this part of the home cooled off. If your home's ductwork would need to be majorly reworked to accommodate central air, your HVAC company might recommend installing central air even if you could do so with your current furnace. (Modifying the ductwork would be really expensive and require major renovations.) In this case, your best options might be window AC units or a mini-split ductless AC unit installed on a wall.

Would the furnace have to be moved?

AC units have an outdoor and an indoor component. The indoor coil box needs to be positioned on or near your furnace so it can be integrated with the same blower unit that your furnace uses to push air through your home. If your furnace is quite old, it may not be able to be integrated with an AC unit. It might also simply be too large to allow room for the AC unit near it. In either case, your HVAC company will likely recommend replacing the furnace before you get AC. On the other hand, if your furnace is only a few years old and has plenty of space around it, you can likely have an AC unit added with little trouble.

Can your home's electrical system handle the AC unit?

If your home's electrical system is a bit outdated, you might need to have it updated before you add an AC unit. However, if you're running a very old furnace, you might be able to get away without having the electrical system changed if you were to replace the furnace and get a new AC unit. This is because newer furnaces tend to draw a lot less power than outdated units.

Every situation is different. Schedule a consultation with your HVAC technician to see whether you can simply add an AC unit to your furnace, whether you'd need to replace the furnace too, or whether you might be better off sticking to window units.