Getting Started with Energy Modeling

Additional service lists are kind of like the list of extra toppings on the menu when you get a burrito.  They seem like nice things, but hey, you’re on a budget, and do you really need guacamole?  Unless you’re ordering a government burrito with mandatory guacamole and extra cheese, you’d be more inclined to pass.

Energy modeling is one of those formerly “guacamole-level” extra services that is fast becoming a standard, not a small part due to the fact that BIM and cloud computing trends are allowing the design team access to what was once a prohibitively intensive engineering exercise, and earlier in the process than ever.  The days of shipping this task out to a specialized consultant that is not familiar with the design concepts and intents should be numbered.

Wading into the swamp of regulations, modeling engines, measurement standards and codes can be daunting, and even if you were fluent in such things a few years ago, the field is changing so quickly that you may have missed some things.  Having taken the LEED exam 7 years ago, I can attest to that.

How do I start?

To make a plan, you have to know where you are and where you want to be.  This means identifying your local requirements, and then setting goals for the project; or more simply: What do I have to do, and what do I want to do?

If you’re not familiar with your local requirements, a good place to start is with the DoE:

There may be local requirements that one-up the state adopted codes, such as New York City’s Local Law 85, so be sure to check with local approval entities.  States will either adopt ASHRAE 90.1 versions directly, or the corresponding IECC (International Energy Conservation Code) which allows either ASHRAE 90.1 or its own prescriptive requirements to be used.  ASHRAE 90.1 updates are issued every 3 years (2007, 2010, 2013…) and 2 years later, IECCs are updated (2009, 2012, 2015…).

So you know where to start, but how far you want to go?

First we have to quantify distance and orient ourselves in terms of scale.  One very helpful metric that does exactly this is EUI (Energy Use Intensity).  Measured in energy used per square foot per year, it goes a long way in leveling the data of very different buildings to give you at least some hope of a meaningful comparison.  This kind of data is being collected on existing buildings by several entities and some are available to sort through such as

The DoE’s Building Performance Database - allows you to filter lots of data on existing buildings by many useful criteria, though some regions are better represented than others:

The New Buildings Institute - collects projects that seek to be leaders in energy efficiency, less a look at standards and more at goals:

ASHRAE 90.1 - uses DoE data to establish benchmark EUIs for different building types, with the intent being to display what compliance with 90.1 meant at a certain time.

When you sort EUIs by Climate Zone and Building Type, all of a sudden you have a very useful means of measurement specific to your project.  Another benefit of EUI, is that you can plug in energy costs of your region and get a much more persuasive unit of measurement:  $$$.

So how far do you want to go?  It depends on your client’s motivation and while it may be marketability or a sense of civic responsibility, it is likely tied to performance savings.  At the concept stage, you can introduce these tools to display the benefits in a more concrete way.  
Once everyone is on board, you will need to pinpoint a destination.  Some predefined destinations include:

LEED ratings:  The current LEED uses ASHRAE 90.1-2010 as its reference point, setting its requirements as the minimum, and linking percentages exceeded to points in its rating system.

The 2030 challenge:  An architect-led initiative that works with the building design and planning industry and governments towards the goal of carbon-neutrality by 2030.  In a white paper, they define goals relative to existing codes and rating systems:

Design to Earn the EPA Energy Star:  The same Energy Star program your microwave participates in has its own building rating system that heavily utilizes EUI, and emphasizes energy use of a facility exclusively, as compared to LEED which is a much more holistic and vertically-integrated view on green buildings.  Still, Energy Star goals can be used to inform how efficient a project is aiming to be.

You may have less specific motivations, more along the lines of performance and monetary payback.  If you don’t shoot for a Brand Name™ energy goal, once again EUI can serve as a concrete monetized target to shoot for.

So you know how to start, and where you’re going, but how do you get there?

Short answer: with an energy model.  As the design process progresses, you can enlist your MEP to head this up, but for architects, the initial siting and form-making fun may happen before one is even on board - or on small or competition projects, you may not have the luxury!  

The options for how to execute this seem numerous and scattered.  I found this chart published by the Building Codes Assistance Project extremely helpful in sorting out options:

The BCAP also does a great job of aggregating resources for architects and discussing in detail codes, processes, and industry dilemmas on most of the things I’ve touched on here.  This white paper is a good place to start:

Now more than ever, it's important to get educated and share these values at every opportunity you have to influence the built environment.