This email was broadcast to several email lists by the Energy Efficient Building Assoc. (EEBA) last Wednesday. It reports on the results of a user survey of building energy software, such as DOE-2.1 and ENERGY-10.

The note includes pointers to several resources for Efficient Buildings:

-> Energy Efficient Building Assoc.

-> US DOE’ Software “Tools Directory”

-> Building Environmental Science & Technology
Bion Howard, Principal bhoward2@sprynet.com

EEBA Computer Software Survey Completed

By: Bion Howard 10/97 (originally published in EEBA Journal)
contact:

Using the EEBA “open” e-mail server, EEBA associate staff solicited comments on energy efficiency design analysis and ratings software. A preliminary report has been compiled from over 40 responses sent back via the EEBA list, and other sources.

Findings from this unscientific fact-finding survey, sent to a total of 1,100 email addresses across three major list-servers (EEBA-L, Greenbuilding, and AESP-Net ) designers, engineers, architects and builders widely disagree on the usability and reliability of currently available computer tools on the market or available from the Department of Energy and other government sources. Several general themes emerge from the survey results:

1. energy design analysis software must be made easier to use; while
2. also being able to produce very accurate and detailed outputs suitable for sharing with clients;
3. it should have a graphical interface, rather than large tabular data screens;
4. the program code should be well validated preferably with peer-reviewed papers available on the results of verification / validation efforts;
5. outputs should include recognition of major energy efficiency standards and model codes compliance;
6. users should be able to access extensive help-screens, and all the data base entries for editing costs, weather inputs, economics parameters; and
7. software engineers should not forget about the large base of Macintosh users in the energy and architectural field when creating new programs.
8. execution speed of the programs should be quick without great sacrifice in accuracy of results, and
9. the ability to share data with AutoCAD was also mentioned by some respondents as an important attribute.

Building types on which analysis was focused by users were evenly split between residential and commercial and about 2/3 of the respondents indicated they performed both commercial and residential work. Also, nearly half of respondents indicated they used software for “energy ratings” and for demonstrating “code compliance.” Other answers included R&D assessments, weatherization assessment, and utility program evaluation.

Surprisingly less frequent were responses indicating use of software for HVAC system sizing. However, this may be mitigated by the fact the question did not exclude HVAC sizing from the “commercial” or the “residential” category. In fact there were several comments in the responses that software for energy design should be improved specifically to do a better job sizing equipment and distribution systems in a “whole building” context. This approach would permit changes in envelope design, passive solar and daylighting, ventilation strategies, and other modifications to the “loads” side of the equation to be rapidly digested to prepare revised equipment and distribution system sizing data.

Responders reported US Department of Energy’s “DOE-2.1” program was most widely used, followed by (in order of frequency) HOT-2000, MicroPAS / CALPAS, ENERGY-10, ASEAM, MEC-Check and Aec-REM. However, due to the small relative response there is no statistical significance associated with these responses (Note: EEBA does not yet officially endorse any computer programs for evaluating energy efficiency, but is currently considering doing so).

Most persons indicated they have been using computer software for energy analysis for over three years, with many responding that they have been using software for energy design analysis for over five years. Five responders indicated they have been using software for over 15 years ‹ so the population surveyed appeared to be fairly representative of both newer and veteran users. Also, five responded they had been using software energy design analysis tools less than three years.

Conclusions from the EEBA software survey are fairly simple.

– Users seem eager to have more functionality and whole buildings analysis capability embedded into energy design software.

– Many users have considerable experience over many years with such software, yet while DOE-2.1 was mentioned as the most frequently used program, there was no single software package that received high praise.

– There were some positive comments about the new NREL-PSIC program “Designing Low Energy Buildings” ENERGY-10 by respondents (ENERGY-10 is still under development and Version 1.2 is expected to be released in early 1998).

– Another new software package ‹ the Wright Soft “Suite” ‹ of energy analysis programs including the Wright-J program (computer version of ACCA’s Manual J cited in the EEBA Criteria) was not checked by any respondent.

EEBA will be continuing to look into the broad array of energy design software to help its members focus in on the top products providing best results. But from my experience as a user of most of the programs mentioned in this article ‹ some since 1978 ‹ it is most vital to become very familiar with whatever software you use, so errors can be avoided and so that limitations to the results are understood (all programs are limited compared to the “real world” they try to model).

Sources: More information on energy design analysis computer software can be found at the US DOE’ Software “Tools Directory”
Information on EEBA: 501[c.]3 non-profit organization
Contact: Bion Howard, Principal, Building Environmental Science & Technology
bhoward2@sprynet.com