Small Gas Boilers

If you are considering the purchase of a gas boiler, add residential boilers (Figure 1) to your list of options. Even though they are designed for a different market, they can play an effective role in commercial buildings as well. Residential boilers are manufactured in larger quantities than commercial units, which makes them relatively inexpensive and readily available with a wide variety of options. Their small size enables them to be easily moved into and out of buildings, and the most efficient residential units exhibit efficiencies similar to those of their best commercial counterparts. In addition, multiple small boilers can be staged to provide high efficiency over a wide range of heating loads.

Figure 1: Residential boiler
Boilers come in a variety of configurations using cast-iron, steel, or copper heat exchangers with different types of burners and venting systems. In the example shown, cast-iron “wet walls” connected by copper finned tubes contain hot water that has been heated by a gas flame. The system is vented by a natural draft chimney.
What are the options?
How to make the best choice
What’s on the horizon?
Who are the manufacturers?