Different Types of Heating

In the past, we here at TJ’s HVAC in Denver have talked in depth about the heating essentials, like how furnaces work and the very basics of HVAC. But we’ve never talked about the different types of heating available to homeowners. Forced air, boilers, and heat pumps are the most common options, and each of them has pros and cons

Wondering which heating system you have? Are you looking for a more efficient heating system? Keep reading to learn more about the different options available to you!  

  • Forced Air:

    • We’ve mentioned forced air before, but a quick recap would be this: these heating systems work by blowing heated air through your ductwork and vents. Furnaces are the most common tool for forced air heating.  

      • Furnaces:

        • Gas: Gas furnaces use either natural gas or propane. When the thermostat calls for more heat, a pilot light in the furnace lights the source gas. This then ignites burners in the combustion chambers and heat enters heat exchanger. From here, heat is transferred to the air so the indoor temperature reaches the temperature set on the thermostat. 

        •   Electric: Electric furnaces have many heating elements. In basic terms, there are electric coils in an electric furnace. When heating is needed, the electric coils are turned on and burn hot. The more heating that is required, the more elements will turn on. Blower fans distribute the warm air.  

Now that we’ve covered the different options for forced air heating, we’re going to talk about hot water heating systems and boilers. Boilers are typically found in the basement in a room separate from the rest of the house. Because they’re full of hot water and steam, they can be very dangerous in the event of a burst or a leak. Make sure not to go into the boiler room if you suspect there’s an issue!

  • Boilers:

    • Boilers use hot water or steam that travels through your home’s radiators, and this is where your heating comes from. How that water travels through your home depends on your radiator.

      • Boiler basics:

        • Water is heated to boiling point via fuel combustion. This hot water is blown through a tube submerged in water, which evaporates the water into steam. Gas jets push the steam to the heat exchanger, which is connected to a pipe carrying cold water. The heat exchanger takes heat from the jets and heats the cold water. Water passes through each radiator, and then back to the boiler. The boiler needs to keep firing in order to keep water at a hot enough temperature to warm your home.  

      • Hot Water Radiator: 

        • Water is heated from central boilers as they continue to run water through the system. Hot water radiators can be hidden in baseboards, or they can be the stereotypical standing radiators that we commonly see in older homes. There are one- and two-pipe hot water radiator systems.
          • One pipe: hot water leaves the boiler, then moves in a loop through the home and returns to the boiler, to be heated and then sent out again. 
          • Two pipe system: hot water leaves the boiler in one pipe, circulates through the home, and is then brought back to the boiler in another pipe. 
        • Keep in mind that these boilers do not increase humidity in a room, which could definitely be a drawback to having them in Denver. 
      • Steam Radiator:

        • The steam for steam radiators is created in a heating area away from where people are. Similar to the hot water radiators, there are one pipe and two pipe options. 
          • One pipe: single pipe runs from the boiler to radiators. Steam is pushed through pipes to radiators, the steam condenses, then is sent to the boiler as water. 
          • Two pipe: one pipe brings steam, the steam condenses, then water is brought is brought back to the boiler in a separate pipe.
        • While steam radiators can help manage the humidity in your home, there are some drawbacks. Steam radiators can warp floorboards underneath them, and they can create lots of noise! The sounds of clanking pipes and hissing steam are common.
        • In general, steam radiators are being phased out due to leakage and the unpredictability of their hot water movements. Since hot water radiators use pumps as opposed to naturally flowing steam, their air movements can be controlled much more easily. 


Boilers and forced air systems may be the most common heating systems, but due to the renewable nature of heat pumps, these are growing in popularity!

  • Heat pumps:

    • Heat pumps are exactly like they sound. Instead of using artificially heated air or hot water to heat your home, heat pumps take advantage of the naturally occurring heat and pump it into your home. These heating options are typically considered “greener” than forced air or boilers, as these do not use fuel.  

      • Water source:

        • Heat pumps collect heat from nearby bodies of water. Water is cycled through pipes that are laid out at the bottom of a body of water. In the winter, heat is gathered from the water reservoir, and carried back to the home via pumping. This hot water is then used to heat your home. The process in the summer is reversed, so heat is carried from your home to the outside. The appropriateness of using a water source heat pump depends on the climate of the area, as well as access to a water source

      • Air to air:

        • This is the most common heat pump system. Heat is moved rather than converted from combustion, like forced air and boilers. Every day, all year, heat is collected from outside (even cold air has a decent amount of heat in it!). Because heat is being brought in from outdoors, air to air heat pumps can dehumidify your home and save money on energy bills. While these were recently not used in places with extensive sub-freezing temps, this isn’t an issue anymore.

      • Geothermal:

        •  Geothermal is heating collected from the ground. While this definitely costs more to install, geothermal heating saves tons of money because it takes advantage of constant ground temperatures. In some cases, your energy use decreases by 30-60%. Humidity is also easily controlled, the heating is reliable, flexible, and available in many homes. Geothermal heating is also available in more extreme climates than air-source heating. 

Which heating system have you found the most reliable? Let us know in the comments!