Efficient Rooftop Units (ERTUs)

As part of the market transformation initiative (MTI) development process, CalMTA is advancing high potential ideas in batches throughout 2024 and 2025. The first set of ideas to move forward are highly scored, but also are most ready for near-term development. These and future ideas for development are being selected from the 117 ideas submitted through the Request for Ideas (RFI) held in summer 2023. Additional information on the status of each idea received during the RFI is detailed in a draft Stage 1 Disposition Report. 

CalMTA has created Advancement Plans for each of the technologies moving forward. 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).

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 Efficient Rooftop Units 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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