Incorporate Energy Efficiency into Tenant Improvement and Renovation Projects with Integrated Systems Packages

What are Integrated System Packages?

Upgrading existing commercial buildings through energy efficiency retrofits will be a key component of decarbonizing the building sector to fight climate change. Yet, despite the evidence and widely available technology, the inconveniences and costs associated with efficiency retrofits are standing in the way of broad adoption. Integrated System Packages (ISPs), developed by researchers at the Lawrence Berkeley National Laboratory with support from the Department of Energy (DOE), are quasi-standardized retrofit packages that can be seamlessly integrated into the real estate lifecycle – during tenant fit-outs and renovations. These packages enable easier and cheaper energy upgrades for office buildings by reducing disruption to building occupants and cutting costs.

Why Are They Important?

Energy efficiency retrofits are most commonly approached as standalone engineering projects, which, when implemented one after the other, are highly disruptive to building occupants and activities. Systems-based efficiency approaches are becoming increasingly recognized as the most effective method for deeper energy and cost reductions. However, systems-based approaches often require significant engineering expertise for proper design, integration, commission, and operation. That’s where ISPs come in. ISPs can be incorporated into standard real estate lifecycle events – tenant improvements, equipment replacement, and renovations — to reduce disruption to building occupants, and the pre-engineered nature of the packages minimizes additional expertise and costs.

LBNL has developed ISPs for three common real estate events: tenant fit-out, rooftop unit (RTU) HVAC replacement, and full building renovation.

What are the different types of ISPs and their impacts?

Tenant Fit-Out ISP:

The Tenant Fit-Out ISP can be incorporated into a routine tenant improvement. The package includes (a) lighting upgrades, such as LED fixtures, occupancy-based controls, and daylight dimming controls, (b) HVAC controls upgrades in line with ASHRAE Guideline 36, and (c) energy monitoring. The HVAC controls include trim and response for supply air temperature and duct static pressure, demand-controlled ventilation, intermittent ventilation, and zone sequences. Optional measures include network lighting control systems, plug load controls, automated interior shades, and ceiling fans. Simulation analysis showed significant energy savings associated with the Tenant Fit-Out ISP, which were then validated by laboratory testing in LBNL’s FLEXLAB. The laboratory results show lighting energy savings from 69-84%, HVAC savings from 20-40%. The simulation results show whole-building energy savings from 23-38%.

Roof Top Unit (RTU) Replacement ISP:

The RTU ISP can be integrated into an RTU replacement project. This package includes a high-efficiency RTU, advanced controls based on ASHRAE Guideline 36, and energy monitoring. Optional measures include window films and cool roofs to reduce the HVAC load. Simulation and laboratory results showed 12-18% energy savings from the RTU Replacement ISP.

Building Renovation ISP:

Any routine building upgrade can incorporate the Building Renovation ISP. This package includes LED lighting and daylight dimming controls, high-efficiency RTUs, HVAC controls based on ASHRAE Guideline 36, and energy monitoring. Optional measures include ceiling fans, automated interior shades, window films, cool roofs, and plug-load controls. Simulation results showed the savings associated with this ISP range from 25-45%.

For the ISPs with RTU replacements, projects are strongly encouraged to consider all-electric replacements, with heat pump RTUs instead of furnace-based heating. In fact, California’s Title 24 code requires all-electric replacements for packaged units depending on size and location, starting January 2023.

ISPs in Action

CBRE – a large property management company and partner in the development of ISPs – manages several properties for a financial institution in the Southeastern U.S. When one property, a bank in Birmingham, was planning facility renovations for exterior lighting and rooftop solar PV, CBRE saw an opportunity to pilot the Tenant Fit-Out ISP. With the addition of the ISP, the project scope was expanded to include interior lighting upgrades, including LED lighting and daylight-based dimming, and HVAC controls upgrades based on ASHRAE Guideline 36, including static pressure reset, heating lockout, zone-based scheduling, optimized start, and widening deadband to 4°F.

Since the bank did not have an energy monitoring system and was not large enough to justify an installation, CBRE used interval data from the utility to measure energy consumption loads and savings from the upgrades. The savings calculations showed 25% energy savings for the entire retrofit – 6% from the exterior lighting upgrade and 19% from the additional ISP measures.

CBRE gave the lighting and HVAC contractors Tenant Fit-Out ISP template specifications for the renovations. While straightforward for the lighting upgrades, the HVAC controls specification did require some customization because the Guideline 36 measures depend on which HVAC system is used. Since the pilot in Birmingham, LBNL has developed an ‘ISP specifications generator tool’ that allows users to base ISP specifications on the specific characteristics of a site. Full toolkits are now available for all ISPs. Chris Pelrine, the Director of Energy Sustainability at CBRE said: “the ISP toolkits offer the ability for project developers and planners to easily apply energy efficient standards into the design specifications of the project. The toolkits will not only streamline project execution but will also allow the planner to estimate the energy savings. This will aid in the approval of any potential cost increase due to installing energy-efficient equipment.”

By integrating the Tenant Fit-Out ISP into a routine renovation, the Birmingham bank was able to achieve 19% higher energy savings. What’s more, the expanded project led to minimal additional disruptions or costs because contractors were already in place for the exterior lighting upgrades and rooftop solar installation.

In summary:

Energy efficiency retrofits will be a critical part of the U.S. building sector reducing its carbon emissions to meet climate goals. By integrating ISPs into the standard real estate lifecycle, these retrofits no longer have to be expensive special projects that disrupt building occupants and activities. Furthermore, the standardized efficiency packages streamline the retrofit process and reduce engineering requirements. Put simply, ISPs make energy efficiency easier and cheaper for building architects, owners, and occupants. To learn more, please check out the ISP toolkits at LBNL’s website:

Get started right now

  1. If you are designing routine tenant fit-outs, RTU replacements, or full renovations for a building, consider incorporating an ISP into the process to enable deeper energy and cost savings. Check the applicability guides for the ISPs. Use the specifications templates to reduce the level of design and engineering effort.
  2. Explore the ISP toolkits online at:
  3. Share knowledge about ISPs with owners and other stakeholders.


  1. Integrated System Packages, LBNL website:
  2. CBRE case study
  3. Energy Efficiency Package for Tenant Fit-Out: Laboratory Testing and Validation of Energy Savings and Indoor Environmental Quality. Energies 2020, 13(20), 5311;
  4. Package deals for deep savings: Scaling deep retrofits in commercial buildings with integrated systems packages. ACEEE Summer Study on Energy Efficiency in Buildings. August 2020. Technical Report
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