H4. Replace Inefficient Heating Plant

Description

Replacing the old heating plant in a building can generate considerable savings if the existing equipment is inefficient and/or the fuel source is expensive compared to other options. A boiler or furnace near the end of its useful life is a particularly good candidate for replacement with high-efficiency equipment.

For this ECM, we discuss several options for replacing the heating plant. To evaluate the cost-effectiveness of other options, consult an experienced professional.

Older furnaces and boilers may not operate as efficiently as they did when they were new, particularly if they have not been properly maintained over the years. In addition, because of technology advances, new boilers and furnaces are much more efficient than they use to be, presenting opportunities for saving on heating costs. Replacing the heating plant also provides an opportunity to switch to a less expensive fuel type. For example, where electricity is expensive relative to gas, it may be cost-effective to replace the heating system with a high-efficiency gas system. Heat pump technology has advanced over the past decade, making heat pumps an attractive option in some applications.

Applicability

• Single-family and multifamily buildings
• Central boilers or furnaces with combustion efficiency of less than 60 percent, if the burner is forced-draft (power burner)
• Central boilers or furnaces with combustion efficiency of less than 75 percent, if the burner is natural draft (atmospheric burner)
• Electric heating systems in areas where electricity is expensive relative to other fuels

Types

• High-efficiency gas- or oil-fired boilers
  • 85-percent AFUE oil boilers
  • 85-percent AFUE gas boilers
• High-efficiency gas and oil furnaces
  • 90-percent AFUE gas furnaces
  • 90-percent AFUE oil furnaces
• Efficient electric heat pumps
  • 12 SEER/7HSPF air source heat pumps
  • 13 EER/2.8 COP geothermal heat pumps

Considerations

• Perform a life-cycle cost analysis prior to replacing major systems.
• Consult a qualified engineer when evaluating heating system replacement and installation.
• Boilers and furnaces should be properly sized for the building.
• High-efficiency boilers can be installed in a modular configuration of several smaller boilers instead of one large boiler.
• Other heating system ECMs should be evaluated as alternatives or complements to this ECM.
• Before installing a new heating system, cost-effective architectural measures should be installed.

Performance/Economics

• Efficient gas and oil boilers:
  • Condensing boilers with AFUEs above 85 percent are the most efficient
• Efficient gas or oil furnaces:
  • Condensing furnaces with AFUEs above 85 percent are the most efficient
  • Multi- and variable-speed furnaces provide enhanced comfort and efficiency
• Efficient electric heat pumps:
  • Heat pumps are 1.5 to 3 times more efficient than electric resistance heat

Resources/Links

Energy Conservation for Housing – A Workbook, HUD, September 1998. Pages 7-53 through 7-57 address replacing inefficient heating plants.

Energy Performance Contracting for Public and Indian Housing: A Guide for Participants, HUD, February 1992. Pages 23 through 26 address heating system opportunities under performance contracting.

ENERGY STAR Program: Heating and Cooling Equipment. Provides information on high-efficiency heating products, tips on finding a contractor, and guidance on sizing and installation.

Improving Energy Efficiency in Apartment Buildings, American Council for an Energy-Efficient Economy, 1995. ISBN 0-918249-23-6. Pages 68 through 88 address heating plants in apartment buildings.

Heating and Cooling Your Home. Discusses modifications to increase the energy efficiency of heating plants.