When it comes to describing HVAC types, there’s a lot of jargon that will nibble your mind away. The systems can be single stage power-vented, multi-stage with variable speed, allow for static pressure, true modulating, and more.

We’ll simply divide the HVAC into two parts:

  • Choosing a furnace type
  • Choosing an AC type

Only by selecting the best combination of furnace and AC for your home can you claim to have bought the best HVAC for your needs. Let us see the types available out there.

Types of Furnaces

The most common type of heat pump used in the U.S is the gas-fueled, forced-air heating. Generally, furnaces can be classified into three categories:

  • Single-stage
  • Two-stage
  • Modulating

Their primary differences are the way how they regulate the temperature and the control options they provide. If you were to think of furnaces like a stove with a control knob, then this is how they will look to you:

  • Single-stage — This type of a furnace has only an “ON”. You turn the knob and it goes to its flaming peak. This obviously consumes a lot of energy and the only option of controlling the heat is to turn it off and hence let the cold almost completely take over if not switched on again.
  • Two-stage — This type of furnace lets you turn the knob to a high or low setting, with nothing in between. It is more efficient than the single-stage as it lets you keep a minimum level of heat.
  • Modulating — This type of furnace has a full turning knob and allows you to set the heat in between high and off. Furthermore, it automatically adjusts its flame and keeps the air temperature constant.

Types of AC

An air conditioner unit can be categorized as:

  • Cooling Only — These are the ACs that can only absorb heat content from the air
  • Heat Pump — These ACs can both cool and heat the conditioned air.

Each can be further classified as follows:


These units can further be divided into split systems and packaged systems.

  • Split System — the unit is divided into an indoor air unit and an outdoor condensing unit. The indoor unit contains the cooling coils, sucks in the warm air, filters and conditions it to lower temperature levels. The outdoor unit contains the compressor and condenser coils. Split systems boast the highest SEER of all AC systems.
  • Packaged-System — the unit contains all the components contained in the split system in one place. As a result, the system is placed outdoors and the conditioned air is transferred through a duct system. They have an SEER rating between 10 and 18.


It is similar to normal AC units (available as a split and packaged system) except that a heat pump can also heat the air inside the room.This article was provided by American AC Heat Plumbing. Since 1981, American Air has been providing professional air conditioning and heating service and repair. Check out their $99 tune-up special – good for your air conditioner or furnace!


James Smith

As you can tell from our humble beginnings in 1981, we began as a family-owned business and stayed a locally owned air conditioning and heating company in Los Angeles county for nearly 40 years.