Efficient Rooftop Units (ERTUs)

CalMTA has developed Advancement Plans for six market transformation ideas. These plans describe the research and investigation that are needed to complete a full MTI Plan to determine a MT theory and scope for future implementation. Below is a summary of the market transformation idea for Efficient Rooftop Units (ERTUs), currently in Phase II: Program Development.

Efficient rooftop unit (ERTU) on a large commercial building. Photo: Danfoss

Portfolio priorities of ERTUs: equity, workforce education & training, energy savings, grid benefits, and GHG reductions

Sector: Small & medium existing & new commercial buildings  

Product Definition: Rooftop units (RTUs) are forced-air systems that package the evaporator, condenser coils, fans, and heating components into a single unit to serve a building’s heating, cooling, and ventilation needs. Three main design improvements addressing supply efficiency, heat recovery, and an improved shell can deliver 10–40% energy savings beyond today’s minimum efficiency RTUs. Greater savings and grid benefits can be achieved through the addition of advanced controls strategies.  

ERTU illustration showing energy-saving features including insulation, low-leakage dampers, improved economizer, and advanced control system

Preliminary Market Transformation Theory: Potential market interventions to tackle the physical design improvements will include manufacturer engagement on affordable product availability and utilization, and development of a California-appropriate tiered rating system that supports better equipment design and purchasing decisions.  

There is currently a national collaborative engaging in this market through a tiered specification approach. The tiered requirements provide both prescriptive and performance paths.  

Read the Advancement Plan

Learn more

Watch an overview of the ERTUs market transformation initiative, including barriers, opportunities, market interventions, and expected outcomes, in this recording from the January 25, 2024 MTAB meeting.

Photo credits:
ERTU: Danfoss
ERTU installation: Helios

Rooftop units make up approximately two-thirds of commercial buildings’ HVAC systems. Commercialized Efficient Rooftop Units (ERTUs) can achieve 10-40% energy savings compared to standard RTUs. Northwest Energy Efficiency Alliance RFI Submission

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