AC / Furnace vs Heat Pump

Air Conditioner / Furnace  vs Heat Pump?  Which do I have and what’s the difference?

Without going too deep into the weeds…  here are the basics.  In the southeast region there are primarily two different types of HVAC (heating, ventilation & Air Conditioning) systems.  Air Conditioner/Furnace  &   Heat Pumps.  

Air Conditioner/Furnace:   This system has indoor cabinet which contains an evaporator coil, fan & gas furnace and an outdoor cabinet which contains a compressor and condenser.  These components work together to deliver both heat and AC.  This system is more common when the home has natural gas available.

During summer the outdoor unit and evaporator coil (indoor) work together to remove heat and humidity from the indoor air and transfer it outside.

In winter the outdoor unit is not utilized.  Instead, a  gas furnace (indoor) is responsible for heating air as it passes through a heat exchanger.

Both types of HVAC systems are controlled by a thermostat.  Air Conditioner / Furnace systems will have three modes of operation:  Heat, Cool & Auto.

Heat Pump

Heat Pump:  The indoor cabinet of a heat pump also contains an evaporator coil and fan but does not have the gas furnace component. The outdoor cabinet contains a compressor and condenser similar to the AC/Furnace system.

So where does the heat come from?  Unlike a Furnace, Heat pumps do not generate heat.  Instead they transfer heat from the exterior cabinet to the interior evaporator coil via refrigerant lines.  Heat pumps are able to efficiently extract heat from outdoors until temperatures reach about 30 deg. F.

If temperatures drop below a preset limit a Heat Pump will automatically switch over to an Auxiliary or Back-Up heat source (aka Emergency Heat or Heat Strips).  This Auxiliary source utilizes electricity to generate heat and is not very energy efficient.  If your Heat Pump is using an Auxiliary or Back-Up source the thermostat will indicate like the ones below.

I said this was the “Basics” at the top of this post.  There are several other combinations of HVAC systems.  Package Units, Boilers,  Splits w/ gas back-up, Mini-Split, Ductless Mini-Split, Swamp Coolers, Electric Coil, Window Units…  Stay Tuned to this Blog for more HVAC posts.

Visit www.RiverCityHomeInspection.net for more information on your home or your next purchase.

Ryan Olson

River City Home Inspection

502-338-4404