Setting out to retrofit an existing building for energy efficiency upgrades can be a daunting task‐ understanding and selecting the multitude of upgrade options available to a retrofit team, from insulation to PV panels is a challenging mix of building science, available resources, and intended outcomes. While many retrofit teams consider worthy metrics such as occupant health and comfort, most retrofit projects will eventually come down to the simple bottom line metric of return on investment. Building owners want to know their investment in the property is well spent, and going to show a return for them in the long run. If a retrofit doesn’t pencil out financially, more often than not, it’s dead in the water.
Energy modeling paired with analysis such as an investment grade audit or energy life cycle cost analysis (ELCCA) is a useful and increasingly critical tool for a retrofit design team in making educated financial decisions and maximizing returns. But what is energy modeling and how exactly can it help guide your decision making process on a retrofit project?
What is Energy Modeling?
Energy modeling in simplistic terms is the practice of taking the unique characteristics of a building and entering that data into computer software. The software in turn has the ability to simulate those building characteristics, as they would act in the real world through visual and data output.
An energy modeler’s role is to collect the multitude of data used in a simulation, including architectural components, mechanical system details, occupancy schedules, building loads, utility bills, and weather data, using all of this to recreate how a building works as a whole system. Often an art as much of a science, a skilled energy modeler needs to have an understanding of not only how buildings function, but also how the software they use simulates the inputs.
In a retrofit project, the first goal is to establish an accurate baseline model depicting how the existing building performs currently. Armed with a model that accurately depicts the way the building functions, an energy modeler can then create deliverables that help the building owner and design team make informed decisions. This includes simple deliverables such as rapid comparative analysis, to more in‐depth investment grade audits and ELCCA reports that measure energy impacts over the lifetime of the building.
How Can Energy Modeling Help My Retrofit Project?
The value of an energy model for your retrofit project is its ability to be used as a comparative tool for evaluating retrofit scenarios that provide the greatest return on investment for a building owner. The detail of analysis, and accompanied confidence in those predictions, is unique to the needs of each project. This is one of the benefits of energy modeling as a tool – it has the flexibility to be used at different evaluation levels based on the needs of the building owners. Once a building baseline model is established that accurately mirrors the way the building is operating, an energy modeler and design team has the ability to use this data many different ways.
On one side of the spectrum, an energy model can help guide a design team through retrofit options fairly quickly, adding and subtracting options such as envelope or mechanical system improvements, gathering energy data on these options, and providing this feedback to the team. This rapid prototyping is a great way to create priority lists of upgrade options early in the retrofit process, while keeping the associated costs of analysis low.
On the other side of the spectrum, an energy model can be the basis of comparison for a much more detailed ‘investment grade audit’. The Level III Energy Audit, which is considered the standard process for energy efficiency upgrades in the US among many large corporations and government entities, utilizes computer-simulated energy modeling in creating investment grade deliverables.
An ELCCA report, similar to a Level III audit but with a more open and subjective format, also utilizes energy modeling as the basis of the report. Combining a model’s energy output data with first, maintenance, repair, and replacement costs of different retrofit options, an ELCCA measures long term cost implications over the effective lifespan of a building. Either one of these reports gives a design team a large degree of certainty and confidence that can significantly help make smart retrofit decisions.
Whatever level of analysis your project may need in helping guide retrofit options, it’s worth noting that the level of accuracy and confidence of your reports rely solely on the experience and talent of the building modeler. This is why selecting a qualified and experienced energy modeler is one of the most critical steps for any retrofit project using energy modeling.
What Should I Look for When Hiring an Energy Modeler?
There are two competing designations in the energy‐modeling field to help you identify energy modelers that have 3rd party credentials. The Building Energy Simulation Analyst designation is awarded by the Association of Energy Engineers (AEE) while the Building Energy Modeling Professional Certification is awarded from the American Society of Heating, Refrigerating and Air‐Conditioning Engineers (ASHRAE) American Society of Heating, Refrigerating and Air‐Conditioning Engineers (ASHRAE).
Either one of these designations gives some clout to an energy modeler, verifying that they have experience in the field and a deep understanding of the modeling process. While this doesn’t mean that you must have one of these designations to be an excellent energy modeler, in this emerging and complicated field it is a good idea to seek out a modeler that has gone through a certification process.
In the end, a building owner’s due diligence in selecting an energy modeler is key to a project’s success. While 3rd party certifications provide some level scrutiny, energy modelers often specialize not only in the depths of analysis but building industry types as well. Checking references on an energy modeler’s past projects and matching their experience with your team goals will ultimately help you achieve your retrofit goals of saving energy, money, and maximizing return on investment.
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