Short-Term Test Results: Multifamily Home Energy Efficiency Retrofit

Stacey Rothgeb, Stacey Rothgeb (NREL Technical Monitor)

Research output: NRELSubcontract Report


Multifamily deep energy retrofits (DERs) represent great potential for energy savings, while also providing valuable insights on research-generated efficiency measures, cost-effectiveness metrics, and risk factor strategies for the multifamily housing industry. The Bay Ridge project is comprised of a base scope retrofit with a goal of achieving 30% savings (relative to pre-retrofit), and a DERscope with a goal of 50% savings (relative to pre-retrofit). The base scope has been applied to the entire complex, except for one 12-unit building which underwent the DER scope. Findings from the implementation, commissioning, and short-term testing at Bay Ridge include air infiltration reductions of greater than 60% in the DER building; a hybrid heat pump system with a Savings to InvestmentRatio (SIR) > 1 (relative to a high efficiency furnace) which also provides the resident with added incentive for energy savings; and duct leakage reductions of > 60% using an aerosolized duct sealing approach. Despite being a moderate rehab instead of a gut rehab, the Bay Ridge DER is currently projected to achieve energy savings >/= 50% compared to pre-retrofit, and the short-term testingsupports this estimate.
Original languageAmerican English
PublisherNational Renewable Energy Laboratory (NREL)
Number of pages34
StatePublished - 2013

Bibliographical note

Work performed by BA-PIRC, Cocoa, Florida

NREL Publication Number

  • NREL/SR-5500-56460

Other Report Number

  • DOE/GO-102013-3796


  • Building America
  • deep energy enclosure retrofits (DER)
  • hybrid heat pump
  • residential
  • residential buildings
  • risk factors
  • savings to investment ratio


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