Budgeting a BEM project

The available project budget has a direct impact on how much time and effort can be devoted to energy modeling, and vice versa. More complex models require more resources but can yield greater accuracy and detail.

Understanding the relationship between budget and modeling detail

Evaluate the Budget Impact

A lower budget may necessitate a more simplified approach to modeling, while a larger budget might support more detailed analysis with multiple iterations and parametric studies.

Example: A small residential project may only require a basic energy model to comply with local codes, while a high-performance building aiming for LEED Platinum may have the budget to support detailed simulations.

Balancing Cost and Accuracy

While a highly detailed model may provide the most accurate results, it can also be resource-intensive. It's important to balance the level of detail with the budget.

Example: For a mid-sized office building, a detailed daylighting analysis may be too costly, but a simplified daylighting model might still yield valuable insights.

Optimize Model for Cost Savings

Energy models can also help identify areas where design decisions can reduce operational costs. By investing in detailed modeling for specific systems (e.g., HVAC), the design team can find long-term savings that outweigh upfront costs.

Example: A detailed HVAC system analysis may reveal opportunities for energy savings that reduce operational costs, justifying the additional expense of a more complex model.

Determining an appropriate budget

Define the Purpose

Preliminary Design Analysis: If the goal is to make preliminary decisions or compare design alternatives, a simpler, quicker, and less expensive model may suffice.

Detailed Analysis or Compliance: If the model is for code compliance, tax incentives, or detailed performance analysis, a more detailed and consequently more expensive model may be required.

Project Size and Complexity

Simple Building: Smaller projects with limited systems may require less modeling effort.

Complex Building: Projects with multiple systems, uses, or unusual architecture might require a more detailed model.

Scope of Work

Are you only assessing energy, or also comfort, daylighting, and other aspects? Integrated models that assess multiple factors can be more costly.

Accuracy and Detail Required

For some projects, a basic understanding of energy consumption patterns might be enough. For others, especially where financial decisions are on the line, a detailed and accurate model is crucial.

Local Codes and Standards

Check if there are local building codes, green building standards, or energy benchmarking regulations that dictate the depth and breadth of modeling required.

Available Budget

As with any service, there is often a trade-off between cost and quality/detail. Understand your budget limitations but also know where to invest for the most valuable insights.

Incentives and Payback

Check if there are any financial incentives available for implementing energy-efficient measures. These can offset the costs of modeling.

Consider the payback period: if energy modeling identifies significant energy savings, the cost of the modeling could be recouped in a short time from the energy savings.

Long-Term Value

While the upfront cost of a detailed energy model might seem high, the long-term value in terms of energy savings, operational costs, and building performance could far outweigh the initial investment.

Expertise of the Modeling Team

Not all energy modelers charge the same rates. The expertise, reputation, and experience of the modeler or modeling firm will influence the cost.

Software and Tools

Different software has different capabilities and cost structures. Some software might be more expensive but could save time and therefore reduce costs in the long run.

Iterations and Revisions

Consider how many iterations or revisions you might need. If your design is still evolving, you might require multiple iterations of the model.

Post-Occupancy Analysis

Decide if you want to include post-occupancy evaluations to validate and calibrate the energy model once the building is in use.

Managing the budget

During the course of the project, be mindful of things that can cause a project to go over budget and try to avoid them, including:

• Scope creep

• Delay in receiving design data (or receiving incomplete data)
• Miscommunication on methodologies, design selections, etc.
• Disjointed workflows requiring rebuilds in different software platforms
• # of model cycles, EEMs, deliverables (and their format), and meetings needed
• Unique HVAC system types that require post-processing
• Design changes that impact the baseline HVAC system selection re-work

Conclusion

In conclusion, the decision of how much to spend on an energy model should be based on the project's needs, the value of the insights gained from the modeling, the potential long-term savings, and the available budget.

Keep expectations clear from the very beginning. Be proactive, not reactive. Extra work may require extra services. Don’t start work until an agreement is set.