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An article appeared in the Telegraph last week, Energy Scandal: Misleading Efficiency Claims Leading to Huge Bills for Homeowners. At IES, while we’re 100% in support of the industry needing to do much more to tackle the energy performance gap, we feel that this article unfairly lays the blame for it at the doors of energy modelling professionals.
Headquartered in Glasgow, IES is the main provider of performance simulation software in the UK. We’ve been helping address the numerous causes of the performance gap for several year’s now, through training and education sessions.
Yes, the ‘performance gap’ is well documented and known about in the industry. But to address it requires action by all those involved in a building’s life cycle, from design to operation. That includes architects, engineers, energy modellers, contractors and facilities managers to name a few. The finger should not just be pointed only at building modelling professionals!
There are a number of issues in play here.
First off, a key misconception to understand, is that an EPC, as modelled by software during the design stage, is NOT a true reflection of how a building will perform once built. EPCs assess a building under normalised conditions, missing out ‘unregulated building energy loads’ that are not required to be included in the calculation. As an industry, we need to get away from modelling just for compliance and modelling for actual building energy use. Read more on our views on this here.
Next up there are already several well-established industry initiatives aimed at tackling the issue. CIBSE Guidance TM54 is focused on ‘Evaluating Operational Energy Performance of Buildings at the Design Stage’, and the BSRIA Soft Landings Process aims to help to solve the performance gap between design intentions and operational outcomes by better management of the handover process from design, through commissioning, and on into operation to deliver a better performing product.
Combine this with, the digital revolution of the construction industry that is Building Information Modelling (BIM), and the industry has a vehicle to capture relevant information during design for use during the operational phase of the building as well as accountability for operational performance.
So what’s the problem? Ultimately, building clients want low fees. To move away from a compliance only modelling approach that uses standard assumptions and leaves predictions of energy use way out, needs the support of clients. When done properly a building model can predict within +/- 5% of energy performance. But time and effort needs to be taken during the modelling process to predict realistic use. And time costs money!
In reality, this research just highlights why modellers use software tools to understand building energy use. The way a building responds in practice is complex with many factors interacting and needing to be accounted for. Modellers use tools like the IESVE to run scenarios and check their assumptions are correct. They often change their views based on feedback from models. The energy modellers that took part in the research were not asked to use any modelling software to inform their responses.
This is why tools like IESVE exist, to aid professionals in making informed decisions. All IESVE modellers can access detailed training and accreditation from us, and we would wholeheartedly support more courses, and in-depth, industry wide accreditation.
In this edition of our Q & AEC blog we will be responding to a question that has popped up quite a few times across our forums and social media pages…
“Does the LEED review panel accept IES-VE as an energy simulation engine? Has it passed the required ASHRAE 140 tests? And has the IES software been used for LEED accreditation of a project?”
Ok firstly it is important to point out that the USGBC do not actually approve or certify software for LEED energy modelling. Instead, LEED depends upon previously established guidelines published by the energy modelling community, in this case the ASHRAE standard 90.1 and associated Appendix G Building Performance rating (PRM). These requirements provide two things for the building owner/developer and design team:
1.Ensures that software used to simulate buildings, in accordance with a set of general software requirements for thermal and energy modelling, includes a sufficient level of detail in terms of hourly dynamic thermal and energy simulation and is of appropriate quality and accuracy for the purposes of the PRM.
The VE has been tested in accordance with ASHRAE Standard 140 and meets or exceeds all requirements of this test. Plus it meets all general requirements of the ASHRAE Standard 90.1 PRM. Click here to download the results of the ASHRAE 140 test. You can also review our EPAct Qualification documents, which provide supplementary details on how we meet these requirements.
2.Facilitates HVAC systems design, control, and performance in accordance with ASHRAE standards and best practices, through a set of mandatory system design and modelling requirements provided by the ASHRAE standard 90.1 and associated Appendix G PRM.
The ApacheHVAC interface provides a stable, dynamic, and robust platform upon which nearly any HVAC system can be designed and modelled, including conventional VAV systems with state-of-the-art airside controls, highly tailored system controls and configurations, waterside free cooling, indirect-direct evaporative systems, desiccant wheels, hybrid hydronic/air systems, radiant chilled/heated floors and ceilings, displacement ventilation, underfloor air distribution, vented stack-effect double-skin facades, earth tubes, and mixed-mode systems that use integrated mechanical and natural ventilation.
In addition to the requirements of 90.1 and 140, Version 6.3 of the VE takes a new approach to assist with LEED Energy Modelling. We have introduced the ASHRAE 90.1 VE-Navigator and enhancements to ApacheHVAC that speed up the process of producing large HVAC networks. This latest version is available to download from our website.
Now let’s take a look at who has used our software to submit reports that have been accepted by the LEED review team. The project that catches the eye would have to be the Syracuse Centre of Excellence in Washington. The SyracuseCoE is a pioneering high-performance green building. It was opened in March 2010 and achieved a Platinum rating under the LEED program administered by the U.S. Green Building Council. This highly impressive rating was achieved by Ashley McGraw Architects with the application of the <VE> and is a project that is at the forefront of green building. They even had some nice things to say about us too — “I would definitely recommend IES to any firm that is interested in designing high performance buildings. IES is a comprehensive, fast, user-friendly package compared to the vast amount of convoluted software available”.
Another project that used our software to acquire LEED accreditation of a building development was the Peterson Elementary School, Oregon. The DLR Group applied the IES-VE as their analysis engine for this 60,000 SF elementary school and achieved LEED Silver certification. You can find some more excellent photos of the school here.
Ok so some of this may have been bordering on blowing our own trumpet but I hope we have given you assurance that our software is being used on LEED projects, in the process of such questionable behaviour!
We have recently been informed by the CLG that the format of files used for non-domestic EPC and DEC lodgments is to change in 1 month’s time. Furthermore, there is no transition period planned — old EPC and DEC lodgment files will simply no longer be active after the switchover date.
All Accreditation Schemes will stop taking EPC submissions created by software using versions of SBEM/EPCGen earlier than the soon to be released v3.3c. This means that Accredited Energy Assessors will have to update their EPC and DEC software to a version able to produce the new xml lodgment files, even if they are in the middle of a project.
Energy Assessors need to plan ahead to make sure that they can maintain business continuity and minimize disruption, but the short timescale might mean that the new software is not available until right before the deadline. A new version of SBEM is due early April and IES will be working flat out to update its SBEM, DSM and DEC software in time. However, we are still waiting for the release of final details and anticipate that we will be left with a period of around 2 weeks (including Easter) to amend, test, gain CLG approval and distribute the new version to our users! We’re making every possible arrangement to ensure we meet this 25th April deadline.
The switchover date is pretty firmly set as Saturday 25th April.
IES have asked CLG for a transitional period and we hope that this will be accepted in order to allow our customers, and other Energy Assessors, to changeover at the time that suits them. However, initial discussions have not been promising on this front.
David McEwan — IES UK Director
There is a growing concern from many in the industry that competent surveyors might be banned from collaborating with accredited Energy Assessors on the creation of commercial EPCs.
CLG recently issued a widely distributed draft directive to the Accreditation Schemes relating to the department’s concerns about the use of data gathers. This was in response to questions being raised about the accuracy of some of the EPCs being submitted. It set out possible changes to restrict the collection of EPC data by those other than qualified Energy Assessors, which could limit the scope for competent surveyors to collaborate on the production of accurate EPCs.
It’s become evident that standards need to be set and there should be no place for data gathers of dubious accuracy. However, the suggested allowance for Level 4 and 5 assessors to use ‘data gatherers’ under certain conditions appears to be too restrictive to meet the needs of a struggling industry.
CLG should be cautious before jumping to any snap decisions. Accreditation Schemes need sufficient flexibility to encourage the right experienced professionals to collaborate on EPCs especially on more complex buildings where data gathering and EPC input are inevitably more specialist tasks.
It’s a difficult tightrope to walk — to put in sufficient measures to raise standards without being too prescriptive. We need arrangements that will allow professional surveyors to work, or even appoint commercial Energy Assessors. EPCs need to be able to improve the standards of building and also fit with the established ways professionals within the industry are already collaborating.