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Enacting a Deep Energy Retrofit

A deep energy retrofit requires a multi-disciplinary team with a “can-do” attitude where the disciplines can constructively collaborate with each other. The design professionals, in particular, should be experienced with integrative design (which is much more than holding one or two design meetings). A successful deep energy retrofit can produce a long-term strategy to phase out energy use in a building to make it super-efficient, more desirable to its occupants, and more valuable to the owner.

We recommend downloading the Managing Deep Energy Retrofits Guide to specify the key action items required for a deep energy retrofit. We recommend the Identifying Design Opportunities Guide for a step-by-step approach to doing integrative design for a deep energy retrofit.

Here are a few of the highlights to the deep energy retrofit process:

Technical Potential

Often owners or design teams target a somewhat arbitrary percentage of energy cost savings as part of the retrofit. Instead, imagine if you had no economic and other non-technical constraints whatsoever. Now estimate the lowest possible energy consumption. This is the “Technical Potential” for your building. Then, begin adding in constraints to achieving this potential, as shown in the diagram below, to arrive at the “Achievable Potential.” The process of adding in constraints will allow you to minimize them and to understand the reasons why you are not able to achieve the Technical Potential.

Right Steps in the Right Order

Many retrofit practitioners will begin design by thinking immediately about what mechanical and lighting equipment they need. We recommend this approach instead:

  • Identify the specific end-user needs so you know the purpose of your design.
  • Then, understand the existing building systems and how well they work.
  • Next, consider passive features and load reduction before introducing new mechanical and electrical systems.
  • Find synergies between systems and waste streams to create multiple benefits from single expenditures.
  • Finally, optimize controls and realize the intended design.

Modeling energy and life cycle cost

Design teams can use energy modeling as a tool to inform design and to predict energy use. It enables analysis that is necessary for deep retrofits: passive design analysis (such as daylighting), energy reductions from bundles of measures, and reductions in cooling/heating loads. In addition, design teams can modify and calibrate the energy model to the post-retrofit building in order to support savings verification and on-going savings.

In concert with energy modeling, design teams can employ a life cycle cost model to calculate life cycle cost. Life cycle cost analyses should include (but often do not) examining bundles of efficiency measures in relation to a business-as-usual scenario and estimating capital cost savings from equipment downsizing.