An Energy Bill Talk / by H

Dear Tiffany,

Thank you for inviting me to the breakfast. I like both pancakes and waffles; they were delightful. 

I have a couple of questions after reading the recent Inflation Reduction Act. Could you or anyone from the breakfast club answer those questions?

First, what does "commercial building'' mean in this bill? (see sec 13303, p353 )

Based on what I understood after reading IECC, the "commercial building" means any building EXCEPT residential buildings of groups R-2, R-3, and R-4 that are less than three stories or less than three stories tall above the ground plane.

Initially, I thought commercial building in this bill meant the same as what IECC defined. However, I am not so confident now because later in section 13304 (page 367), the bill also has other incentives for buildings to participate in the Energy Star Multifamily New Construction. In their requirement, all residential new construction are eligible EXCEPT two-family dwellings.

My friend lives in a newly constructed two-story apartment with slope-enhanced attic space. Will that building meets IECC's "commercial building" definition? If it is considered a "commercial "building and participates in Energy Star's multifamily program, will my friend's apartment qualify for both tax credits?

 
 

Second, what does "to be reduced by a percentage greater than 25 percent" mean?

Based on my understanding, three methods exist in ASHRAE to determine a building's energy efficiency level.

  1. the Prescriptive method

  2. the Energy Cost Budget Method

  3. the Performance Rating Method

But only the performance rating method, which uses Appendix G, calculates with a "comparison" measurement. This is what I found in ASHRAE 90.1-2016 G1.3.a:

"A brief description of the project, the key energy efficiency improvements compared with the requirements in section 5 through section 10..."

"This summary shall contain the calculated values for the baseline building performance, the proposed building performance, and the percentage improvement."

However, perhaps because we do not have much time saving this earth, ASHRAE's standards seem to become higher and higher. In ASHRAE 90.1-2013, the way to calculate the energy improvement is: the percentage saving = 1- Performance Cost Index (PCI) (see 90.1-2013, G1.2 “Performance Rating”).

In ASHRAE 90.1-2016, a percentage saving calculation method has changed to the percentage saving =1- Performance Cost Index/ Performance Cost Index Target (PCI/PCI t)

(note: Performance cost index= Proposed building performance/ Baseline building performance, see "Normative Appendix G1.2.2")

I want to use this example to show my point. If a school in climate zone 4A with a building performance factor of 0.49, then its percentage improvement in cost when using version 2013 will be 43%.

  • 1- PCI=1-0.57= 43%

Its percentage improvement in cost when using version 2016 will only be 8%

  • 1-PCI/PCIt = 1- (0.57/0.62)= 8%

In version 2016's formula, the calculated PCI value might be equal to or slightly larger than the PCI target value. In that case, there will be no energy improvement in that building. On the other hand, if people use version 2013, a proposed building performance will always be better than a baseline building performance; thus, there is always a little better improvement. 

Could you or anyone in the breakfast club let me know if I understand this bill correctly?

By the way, may I also know what authority can decide which building can be certified as "energy efficient"? 

Your affectionate friend, Hepburn

Behind the scene:

  • I received the confirmation that the energy efficiency level is based on the most recent ASHRAE 90.1 version in effect four years before the project being placed into service.

  • According to IECC (International Energy Conservation Code) section 202, all buildings except the followings are considered "commercial buildings."

  1. Single-family,

  2. Duplex family house.

  3. Townhouses

  4. The building of use groups R2, R-3, and R-4 has less than three stories.

Many buildings "sound" residential, but they are "commercial buildings" according to IECC's definition. For example, hotel, motel, or vacation time-share property, regardless of their height, is considered a commercial building. 

  • In ASHRAE90.1- 2016's calculation method, the [1- (PCI/PCIt) ] value might sometimes become negative. Thus, "When using appendix G, the Performance Cost Index (PCI) shall be less than or equal to the Performance Cost Index Target (PCIt)." see 4.2.1 Compliance path, ASHRAE90.1- 2016.

  • See ASHRAE90.1-2016 Table 4.2.1.1. for building performance factors (BPF) in different climate zones. This factor is varied by climate zone and building area type. To understand how “BPF" influence the result of energy efficiency level, see the following example.

Assume there are two five-story apartment buildings with the exact energy cost. One is in Napa, California (climate zone 3C), and the other is in Lake, California (climate zone 4B). That building will have better energy improvement when it is located in Lake county, CA. 

To translate how BPF function into the real world, the larger the BPF, the better an energy efficiency level when using ASHRAE 2016. But when using ASHRAE 90.1-2013 method, the final energy efficiency result will be no difference in terms of locations (climate zone). On the other hand, it is not a fair comparison because the same building envelope (material) might have a more significant impact in one climate zone than the other.