Propane Boilers

High-efficiency propane boilers are lowering costs and adding value to homes across the country. They serve a variety of space- and water-heating applications, allowing today’s homeowners to customize their residential energy use.

APPLICATIONS FOR USE

• New Construction
• Replacements/Retrofits

AT A GLANCE

• Available in a wide range of heating capacities with inputs reaching as high as 299,000 BTU per hour.
• Additional end use options include snow melt systems and separate heating zones.
• Energy Star-rated propane boilers have an efficiency rating of at least 85 AFUE.
• The EPA’s “Most Efficient” propane boilers offer up to 19 percent savings over standard efficiency boilers.
• Systems may also qualify for a variety of federal, state, and utility credits or incentives.
• High-efficiency propane boilers result in significantly reduced CO₂ emissions compared with those fueled by heating oil.

High-efficiency propane boilers offer efficiency, space savings, and the versatility to provide heating, hot water, and even snow melt. This versatility also extends to the type of heating delivery system propane boilers serve, including hydronic baseboard systems, in-floor hydronic systems, or even forced-air systems where the hot water from the boiler (instead of a furnace) acts as the heat source.

Propane boilers are available in a wide range of heating capacities with inputs reaching as high as 299,000 BTU per hour. Multiple boilers can also be banked together for even greater capacity, redundancy, versatility, and performance. A residential high-efficiency propane boiler also takes up little space in the home, whether a floor or wall-hung model.

Their ability to supply domestic hot water makes propane boilers ideal candidates for residential installations. Additional end use options for boilers include snow melt systems or separate heating zones in spaces like the garage. Treating these additional applications individually allows homeowners to use them as they see fit, conserving energy while still providing added value.

PERFORMANCE

New high-efficiency boilers are often used to supply hot water to hydronic (meaning hot water-based) heating systems. In-floor hydronic radiant systems eliminate the use of forced-air ducts to distribute heating — which can waste significant amounts of energy. In-floor hydronic systems are also easily zoned using manifolds, so the homeowner can heat different parts of the home to varying set points — optimizing comfort and saving energy too.

Many homes in the U.S. also use air conditioning for the warmer summer months. With hydronic heating, non-ducted air conditioning options include high-efficiency window or wall units or a mini-split system. High velocity ducted central A/C is another option which may be used in climates with more significant cooling loads or larger floor plans.

Examples of in-floor hydronic radiant tubing (left) and a distribution manifold (right).

Propane boilers have an expected lifespan of up to 30 years, according to the EPA, but many boilers can last much longer if serviced and maintained properly. Thus, the initial investment in a hydronic heating system provides long-term value well beyond other heating alternatives.

ENERGY EFFICIENCY

In addition, propane boilers offer high efficiency and energy cost savings. Several hundred propane boiler models qualify for the Energy Star label. This means that the boilers have an efficiency rating of at least 85 percent, as rated by their AFUE. An 85 AFUE rating is actually just the start, as more than 200 of these boilers are also rated as “Most Efficient” within the Energy Star program — achieving efficiency ratings ≥ 95 percent AFUE. By contrast, only seven high-efficiency oil boilers are listed on the EPA’s 2015 “Most Efficient” product listing, allowing a wider range of options for high-efficiency propane boilers. “Most Efficient” propane boilers offer up to 19 percent savings over standard efficiency boilers and represent the best-in-class levels of boiler technology.

Some of the key features in high-efficiency propane boilers include:

• Electronic Ignition—meaning no standing pilot light.
• Condensing Operation—which allows more heat to be extracted from the combustion process.
• Sealed Combustion Operation—so all combustion air is ducted directly from outdoors.
• Modulation Operation—which allows the boiler to adjust its output rate.
• Outdoor Reset—letting the boiler adjust its temperature in response to the outdoors, while also improving comfort and reducing distribution losses.

ENERGY CONSUMPTION & COSTS

High-efficiency propane boilers provide energy, cost, and carbon savings in both new and existing homes. As an illustration of these savings, the table below compares a standard efficiency oil boiler (84 AFUE) with an Energy Star “Most Efficient” propane boiler (96 AFUE) in a typical new 2,400-square-foot home. The propane boiler provides energy savings based on actual 2014-15 pricing while also reducing CO₂ emissions by over 4,000 pounds/year.

High-efficiency propane boilers used for space- and water-heating systems may also qualify for a variety of federal, state, and utility credits or incentives. Visit the Database of State Incentives for Renewables & Efficiency at dsireusa.org to see what incentives may apply.

ENVIRONMENTAL

As the example illustrates, a high-efficiency propane boiler results in significant CO₂ emission reductions compared with a heating oil boiler. Even for propane and heating oil boilers of comparable efficiency levels, a 2013 heating systems analysis (table 1) determined that the CO₂ emissions from a high-efficiency propane boiler were 2,749 pounds (~1.4 tons) lower per year than for a high-efficiency oil boiler for a new, Northeast home. In that same analysis, the CO₂ emissions for a propane boiler-fed in-floor hydronic system were lower when compared with several other furnace and heat pump systems in the Midwest.

Propane boilers offer environmental value inside the home as well. According to the EPA, poorly designed or maintained HVAC systems can lead to reduced air quality. One benefit of propane boilers heating the home via hydronic baseboard or in-floor heating is the elimination of fans and duct systems which can circulate dust, dirt, and other allergens.

PROPANE SAVINGS IN NEW 2,400-SQUARE-FOOT HOMES

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