How can architects ensure that their building performance analysis results are accurate? As designers increasingly take on early-stage analysis, the question is of growing importance. Here are five practices that architecture firms can incorporate to increase confidence in their results.
What’s the problem?
Architects are taking on more and more early-stage analysis for a variety of reasons. Many are driven by increasingly stringent performance requirements, increasingly savvy clients, and voluntary targets like the 2030 Challenge.
There are many positives to this trend. Real data is replacing inaccurate rules of thumb as a guiding force in design. Decentralizing analysis capabilities helps to enhance a firm’s performance literacy over time. And more knowledge of building performance empowers design teams to tackle performance creatively, helping to create a virtuous cycle of better performance and better design.
But architects aren’t energy modeling experts. Many worry that architects could unknowingly produce “garbage” results by accidentally providing “garbage” inputs — and that design teams could embarrass themselves by presenting inaccurate information to clients.
Fortunately, there are a handful of lightweight Quality Assurance steps that firms can take to build confidence in their results.
1. Use templates
One of the best way to avoid “garbage in” is to use templates to standardize input information. There are several common types of input templates:
- Space use templates include internal loads (lighting & equipment), setpoints, and operating schedules for common uses, such as office, lab, or residence.
- Envelope templates include elements like insulation values, window properties, and infiltration rates. They are often based on a standard like ASHRAE Std. 90.1.
- HVAC templates provide typical settings for different HVAC system types.
Envelope, Space Use, and HVAC System templates are available in Sefaira.
Sefaira provides standard templates for all of these and selects appropriate templates based upon a few initial inputs. For example, Sefaira automatically selects a typical HVAC system based upon building type and location and will select an appropriate envelope template based upon location and space use. These defaults provide a solid foundation for users to get good results with only a few inputs.
Firms can build upon these for even more control. For example, creating custom Space Use templates for building types they frequently work on, or custom Envelope templates to reflect the firm’s standard assemblies and details.
2. Create an expert review process
Have an expert — whether an in-house sustainability guru or external consultant — weigh in on the initial inputs and report back on possible improvements. Not only does this provide an accuracy check, but it’s also a great opportunity to jump-start the conversation with consultants or engineers. (For Sefaira users, this can be as easy as granting them access to your project.)
This strategy can be expanded to include expert review of key deliverables throughout the design process. (For more on this, see our article on Early-Stage Architect-Engineer Collaboration.)
A proposed workflow for early-stage collaboration between an architect, sustainability specialist, and mechanical engineer
3. Compare results against a benchmark
While every building will be different, buildings with similar uses in similar climates will likely show a comparable EUI (Energy Use Intensity) and energy end use breakdown. For a point of comparison, you can use an industry-wide source like CBECS, whose data is accessible through tools like Portfolio Manager or Architecture 2030’s Zero Tool. Or you can compare against a later-stage analysis from a similar project — a strategy that could work well for firms that do a lot of similar projects. If there are glaring discrepancies in results between the benchmark and your design, double-check the related inputs.
A comparison against a reference building can help to identify big deviations in total energy consumption, or a specific end use. This example shows good overall agreement, although the lower heating loads may warrant a quick double-check.
4. Present results in relative terms
Even when early-stage inputs are good, the results are still far from predictive, and will likely change significantly as the design progresses. That’s okay: their value lies in their ability to guide design decisions in the right direction, not to predict utility bills. But to avoid sending the wrong message to clients, show results as in relative terms — for example, as a percentage change from a code baseline case — rather than showing hard numbers.
Present early-stage results in relative terms rather than hard numbers.
5. Incentivize training
Designers who are new to performance analysis can benefit from training and deliberate roll-out. Make sure interested designers have an opportunity to pair training with application on real projects. This approach gets newcomers up-to-speed quickly and provides immediate value to the project team and firm. Sefaira’s library of training videos provides a good starting point.
Broad-based training has another benefit: it distributes knowledge of performance analysis throughout the firm. Instead of relying on one or two experts, over time designers can provide feedback on one another’s results.
Sefaira’s training videos provide a good starting point for architects who are new to energy or daylight analysis.
Bonus: Explore Sensitivity
Want to take your understanding to the next level? Use sensitivity analysis to explore areas of uncertainty, such as schedule or internal loads. You’ll discover which inputs have a big impact on results and which are negligible. This will give you a solid understanding of how your model behaves and enhance your ability to discuss the results in detail — and can also help you identify big opportunities for improvement. You can do this type of study fairly quickly in Sefaira using Response Curves. For more detail on this type of analysis, see our post on Sensitivity Analysis.
These strategies can help firms gain confidence with analysis — and ultimately foster a culture of performance that will set your firm apart.