CSI DIVISIONS 01: General Requirements 02: Existing Conditions 03: Concrete 04: Masonry 05: Metals 06: Wood, Plastics, and Composites 07: Thermal and Moisture Protection 08: Openings 09: Finishes 10: Specialties 11: Equipment 12: Furnishings 13: Special Construction 14: Conveying Equipment 22: Plumbing 23: Heating, Ventilating, and Air-Conditioning (HVAC) 23 00 00: Heating, Ventilating, and Air-Conditioning (HVAC) 23 05 13: Common Motor Requirements for HVAC Equipment 23 05 93: Testing, Adjusting, and Balancing for HVAC 23 07 00: HVAC Insulation 23 07 14: Mastic Removers 23 09 00: Instrumentation and Control for HVAC 23 23 23: Refrigerants 23 31 00: HVAC Ducts and Casings 23 33 13: Dampers 23 33 54: Duct Mastic 23 34 00: HVAC Fans 23 34 20: Bathroom Ventilators 23 36 00: Air Terminal Units 23 37 00: Air Outlets and Inlets 23 38 00: Ventilation Hoods 23 40 00: HVAC Air Cleaning Devices 23 40 13: Air Quality Monitoring and Assessment 23 51 00: Breechings, Chimneys, and Stacks 23 52 01: Residential and Small Commercial Heating Boilers 23 52 02: Commercial Heating Boilers 23 52 03: Cordwood, Pellet, and Multi-Fuel Boilers 23 54 00: Furnaces 23 56 13: Heating Solar Flat-Plate Collectors 23 56 14: Heating Solar Concentrating Collectors 23 56 15: Heating Solar Vacuum-Tube Collectors 23 56 16: Packaged Solar Heating Equipment 23 56 19: Solar Heating Balance of System Components 23 57 00: Heat Exchangers for HVAC 23 60 00: Central Cooling Equipment 23 61 00: Refrigerant Compressors 23 64 00: Packaged Water Chillers 23 65 03: Cooling Tower Water Treatment 23 71 19: Off-Peak Thermal Energy Storage Cooling Systems 23 72 00: Air-to-Air Energy Recovery Equipment 23 73 00: Indoor Central-Station Air-Handling Units 23 76 00: Evaporative Air-Cooling Equipment 23 81 00: Decentralized Unitary HVAC Equipment 23 81 26: Mini- and Multi-Split-System Air-Conditioners 23 81 44: Heat Pumps 23 82 00: Convection Heating and Cooling Units 23 83 00: Radiant Heating Units 23 83 19: Radiant-Heating Hydronic Panels 23 84 00: Humidity Control Equipment 26: Electrical 27: Communications 28: Electronic Safety and Security 31: Earthwork 32: Exterior Improvements 33: Utilities 34: Transportation 35: Waterway and Marine Construction 42: Process Heating, Cooling, and Drying Equipment 48: Electrical Power Generation

CSI Section 23 54 00: Furnaces

Furnaces heat air that is then distributed through ducting and warm-air registers.

These listings include the highest-efficiency, sealed-combustion furnaces and high-efficiency wood or multi-fuel furnaces. A multi-fuel furnace uses several sources of energy such as wood, wood-pellets, coal, oil, or gas, with oil or gas operating as backup. One can also purchase wood-only furnaces and boilers without the fossil-fuel backup, or interconnect an “add-on” wood system with an existing oil or gas system. Well-designed biomass-fueled furnaces have very high combustion efficiencies, reducing particulate emissions to less than half of the levels of the best wood stoves.

When wood is locally available and can be harvested sustainably, it has little to no net impact on global warming. However, other biomass fuels (such as corn) may have hidden impacts such as agricultural use of fossil fuels and pesticides or competition with food supply. Use of coal is not recommended due to concerns relating to resource extraction and emissions.

Gas furnaces listed here must have at least 94% annual fuel utilization efficiency (AFUE). Multifuel systems are listed with steady state efficiencies (SSE or SS) of at least 80% using wood and 85% with gas or oil. Multi-fuel systems still lack standardized testing for efficiency and preference is given to systems that provide certification or other verification of testing procedures.

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	Strong Growth for Unvented Gas Heaters, Despite Hazards EBN: Newsbrief - June 2008		Indoor Air Quality Study Supports Replacing Older Woodstoves EBN: Newsbrief - October 2007
	DOE Proposes New Furnace Efficiency Standards EBN: Newsbrief - December 2006		Climate Energy Brings Combined Heat and Power Home EBN: Product Review - September 2006
	Unvented Gas Heaters Still Gaining Ground EBN: Then & Now - May 2006		CEE Record Availability of Efficient Gas Furnaces EBN: Newsbrief - March 2003

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Amana AMV9 Gas Furnace Amana Heating and Air Conditioning Plus 90 High-Efficiency Furnaces Bryant Heating & Cooling Systems Infinity Series Carrier Corp. UltraMAX III ECR International, Inc. Diamond 90 and Diamond 95 ULTRA York International Corp.	Plus 90 High-Efficiency Furnaces Bryant Heating & Cooling Systems
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Books
	The Book of Masonry Stoves: Rediscovering an Old Way of Warming by David Lyle (1998)

ARTICLES Strong Growth for Unvented Gas Heaters, Despite Hazards EBN: Newsbrief - June 2008 More articles PRODUCTS Plus 90 High-Efficiency Furnaces More products BIBLIOGRAPHY The Book of Masonry Stoves : Rediscovering an Old Way of Warming by David Lyle (1998)