ES2: Heating equipment efficiency

• Ducted furnace(s) and/or boiler(s) >90% AFUE, sealed combustion 
• Ducted heat pump(s): 
  • Climate Zones 2, 3: >8.2 HSPF and within 15% of load calculation 
  • Climate Zone 4: >8.5 HSPF and within 25% of load calculation

Purpose

Furnaces with a rated Annual Fuel Utilization Efficiency (AFUE) of ≥90% are equipped with a sealed combustion chamber that prevents provides combustion air from a known location. Sealed combustion chambers have the added safety benefit of being sealed from external conditions, thus reducing the risk of flame roll out and back drafting of combustion products.

A properly sized heating system is designed to adequately condition a space according to the summer and winter loads placed on it. Using oversized equipment results in higher purchase prices and increased day-to-day chargers for use.

Criteria

Furnace(s) ≥90% AFUE and within 40% of load calculation 

• All heating equipment must be ≥90% AFUE for gas combustion furnaces. All furnaces must be sized within 40% of the heating load as determined by the load calculation. If the required fan speed cannot be provided by a smaller unit, a furnace may be more than 40% oversized.

Heat pump(s) Climate Zone 2/3 ≥8.2 HSPF and within 15% of load calculation, Climate Zone 4 ≥8.5 and within 25% of load calculation 

• All heating equipment must be meeting an ≥8.2 Heating Seasonal Performance Factor (HSPF) for heat pumps in Climate Zones 2 and 3 or 8.5 HSPF in Climate Zone 4. 
• Heat pumps in Climate Zones 2 and 3 must be within 15% of the load calculation or the next available size. Heat pumps in Climate Zone 4 must be within 25% of the load calculation or the next available size.

Confirmation 

• The builder must present documentation demonstrating compliance of criteria to the EarthCraft Technical Advisor at the mid-construction inspection 
• The EarthCraft Technical Advisor will review documentation provided by the builder for compliance of criteria and will visually confirm compliance of criteria at final inspection.