Most heating systems we have available today make us feel comfortable by heating the air around us. An open fireplace heats differently.


The hot air produced by a fire in a fireplace should go up the chimney, not into your home. The heat you receive and feel from an open fire is called radiant heat, and this is the same kind of heat we receive from the Sun.


Our bodies generally feel warmer in direct sunlight in comparison to a shady location. The air temperature in the shade, however, is not necessarily different than in direct sunlight! The difference in how we feel is determined by whether or not we are receiving infrared rays from the Sun (radiant heat). These rays are how the Sun heats the Earth.


Think of your fireplace as a tiny sun. The fire in it will heat you and the objects in your room, and over time these objects will heat the air.


Keep the following things in mind as you consider how to get the most out of a radiantly heating fire:


  1. The more objects that that are warmed by the fire, the more heat that will be transferred to the room air.

  2. Since the embers are a great source of heat, it is useful to maximise their exposure with a fireplace grate designed for this purpose (see the links page).

  3. You will generally feel warmer at lower air temperatures while enjoying a good fire.

  4. Even though fireplace screens are essential for fireplace safety, they will block some radiant heat. If you are actively monitoring your fire which is burning wood known not to pop or spit, consider removing the screen. Use wise judgement!  If you leave the room, be sure to replace the screen.

  5. Glass doors are thought by some to increase the efficiency of a fireplace by reducing the amount of room air lost up the chimney. However, tempered glass doors will significantly reduce the radiant heat entering the room. Ceramic glass doors pass through more radiant heat, but they are thought to still block some of the infrared rays.


Next, we’ll look at how to build an effective fire.