Reduce First Cost in a New Warehouse Building: An Example of Performance Path Energy Code Compliance

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Are you throwing away money on your warehouse project?

If you are involved in building a new, air-conditioned warehouse or industrial building, you could be unknowingly wasting money from your construction budget! However, this unfortunate situation can be easily avoided.

We are referring to the powerful benefits of using a performance-based approach for IECC energy code compliance (performance path), as opposed to the significant penalties that may accompany the standard, prescriptive (COMcheck) method of code compliance.

In most cases, the performance path includes these methods of cost savings:

• Eliminating continuous insulation (ci) on the above-grade walls

• Reducing roof insulation levels

• Providing more flexibility on glazing and window selection

• Allowing the selection of more cost-effective HVAC equipment

How is this possible?

The performance path is an alternative code compliance pathway to help avoid overly restrictive energy code requirements and costs. This allows buildings to pass code if the overall energy performance beats IECC by 15%. This differs from COMcheck, which requires each building system (envelope, lighting, mechanical, service water heating) to meet or exceed code, with one designated as an “additional efficiency package”.

The performance path works particularly well for warehouse buildings, because of how this type of building uses energy. Most warehouse buildings operate over long hours, sit on large properties for semi-trucks, and do not need to keep indoor temperatures as warm or cold as a typical building.

As seen in Figure 1, lighting energy represents a large fraction of energy use, and HVAC and building envelope changes are less impactful than a typical commercial building. With a good lighting design, a warehouse building can easily exceed the 15% savings requirement, which allows room for changes in insulation levels or other cost saving strategies.

Figure 1: Example Energy Use Profile of Warehouse in Phoenix, AZ

Energy Code Compliance: A Quick Overview

Using IECC 2018 as an example, there are three possible paths for code compliance, as shown in Figure 2 below. These can be visually explained in Figure 3. For this report, we are considering only IECC Performance (Option 3).

Figure 2: Excerpt from IECC 2018 indicating the possible applications

Figure 3: Visual of possible IECC 2018 compliance options. 

Some important notes:

1. All methods require meeting mandatory requirements. A project then needs to meet prescriptive compliance or performance compliance.

2. There are pros and cons in using IECC vs. ASHRAE 90.1 on any given project.

3. IECC Performance (Option 3) and the two non-COMcheck ASHRAE options use an energy model to demonstrate compliance. IECC requires > 15% savings while ASHRAE requires >0% savings against more stringent requirements.

Example

Here is an example of how the performance path can be applied:

 [1] Office areas are typical, but for simplicity, have been ignored in this study.

[2] Most studies show that upgraded HVAC units have a fast payback relative to their added cost.

Figure 4: Rendering of example warehouse building

Results

Performance Path simulation results are shown in Table 1, below. As the results indicate, the design passes IECC under the performance path by achieving more than 26% cost savings [3]. On the following page, Figure 5 indicates that this design would not have passed COMcheck.

Table 1: Simulation Results

[3] Cost savings based on ‘regulated’ savings which excludes equipment not covered by IECC, such as receptacle loads.

Cost Savings

This example warehouse utilized R-20 insulation – analogous to 4” rigid Polyiso insulation. Most projects will use R-30 minimum (6” rigid). Historical data from RS Means indicates the R-30 insulation would be $0.90/ft2 more expensive. This amounts to over $500,000 in first cost savings! Some architects may also find the wall system cheaper than their normal standards.

It is possible that the reduced insulation levels might require up-sizing HVAC units and/or adding units. In most cases, this expense, if applicable, is still far less than the insulation cost savings.

Wait, why be less efficient?

This is a logical question! However, a better question is: “what is the added utility cost from the reduction in insulation? Table 2 indicates the building would save more than $22,000 annually with R-30 insulation, using actual utility rates. With the $500,000 investment this requires, this is a simple payback of over 22 years! This return on investment (ROI) should be unacceptable to just about every owner and developer.

Table 2: Benefits of R-30 insulation vs. R-20, example warehouse

 Figure 5: Failed COMcheck

What to Remember

1. There are multiple paths for energy code compliance – choose the best one for your project!

2. The performance path for energy code compliance can save a lot of money on the construction budget for a new warehouse!

3. Increasing insulation levels is not always a wise investment!

What about your building?

Are you working on a warehouse or industrial building? Would reducing your construction budget make life easier?

Contact G2 Energy Solutions today for a quote.

About Craig Green

Craig Green is the managing principal at G2 Energy Solutions, an energy engineering consulting firm based in Phoenix, Arizona. Over the last decade, Craig has helped project teams save millions of dollars through the performance path code compliance process over many projects. 

For questions on the article or to discuss working with G2 Energy Solutions, please contact Craig at 480-637-7900 or craig.green@g2energysolutions.com.

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