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Writer's pictureOmer T. Karaguzel
Feb 15, 20213 min read

BENCHMARKING vs BASELINING FOR BUILDING ENERGY MODELS

Without having a reference point the comparative nature of building energy models becomes unuseable. The reference point is the origin of your global coordinate system in your multi-dimensional inquiry space that you traverse with the help of your BEM. In other words, if you don’t have a reference point you won’t be able to answer the question: With respect to What? when you claim that your model indicates a promising 45% of energy cost savings over a year. Therefore, to be able to answer with-respect-to-what question, you’ll need to determine your benchmark or have your baseline ready before the next eco-design charrette. But what is the difference between a benchmark vs. a baseline? Are they just synonyms? Even though these words being used interchangeably to refer a reference point of comparison, they are not the same.


Here’s my take:

Benchmark is pure statistical data that signifies the energy use or energy cost of “actual” or “real” buildings with the same usage patterns and in the same region as your project building. We can open up region to climatic region (climate zone), jurisdiction region (municipality), or a smaller spatial region (such as a building site, campus, neighborhood). Usage patterns is about the type of occupancy such as a 24/7 hospital building should be benchmarked against similar buildings. You can make a more detailed selection criteria to find a more representative benchmarking data to compare your results such as: use and occupant density, location and microclimate, building mechanical-electrical systems, size, number of floors and even orientation of the buildings in the data set.


On the other a baseline is another building energy model and similar to your model it is virtual and can be hypothetical (i.e., not representing and “actual” or “real” building case in operation). Your BEM software can offer a baseline with some default inputs based on your building size, type and climatic location or you can construct a baseline which is basically a starting point or the base model before testing your energy efficient building or system design alternatives. However, there are also structured methods of developing a baseline model and the most well-known is the ASHRAE 90.1’s baseline building definition which is defined in great detail in its PRM (Performance Rating Method). Baseline is not a collection of statistical data as in the case of benchmark but it is a building energy model representation from which you can generate energy and cost data to compare against. You will be comparing performance data in the end and with both options.


Another note is that, baseline models tend to be lousy in a sense that they just perform the base minimum or just representing a building that is acceptable by minimum standards of constructibility or energy efficiency. The expectation is to go beyond the baseline and demonstrate improved performance above the baseline but without compromising the occupant’s comfort and health. That’s why that your alternative model and the baseline cannot differ in required outdoor air ventilation rates, indoor temperature, humidity and luminous set-points.


Here are some resources for your benchmarking and baselining:

The most widely used baseline model is explained in ANSI/ASHRAE/IES Standard 90.1-2016 (Energy Standard for Buildings Except Low-Rise Residential Buildings) which is called shortly as ASHRAE 90.1. Better to check out Normative Appendix G: Performance Rating Method (p 263). More details are also given in an accompanying document to ASHRAE 90.1 which is its User’s Manual (Standard 90.1 User’s Manual). Section G. Performance Rating Method (p. 399).

These publications from ASHRAE are not free. See below:



Note: All web-sites are accessed on February 15, 2021.


Omer T. Karaguzel, PhD

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