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Measurement and Verification

Measure-specific M&V approaches | Sampling guidelines | M&V plan requirements |
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Sampling guidelines

When preparing the Project Application, a Project Sponsor is required to document each fixture or piece of equipment that is part of a project. Equipment with similar functional uses may be grouped together for M&V purposes. Once the equipment has been grouped, a sample of each grouping's equipment may be monitored and the results used to estimate the operating hours for all of the fixtures or equipment within that group. (For more information on specific equipment groupings, see the measure-specific M&V approaches for that equipment type.)

The table below shows how large the sample size must be to provide a reliable estimate for varying sizes of groups. The initial sample sizes represent 80% confidence/20% precision and have a coefficient of variation of 0.5; the suggested sample sizes have been increased by 10% to compensate for equipment failure or loss.

Group
population
Initial
sample size
(80/20)
Suggested
sample size
(80/20 plus 10%)
4
3
4
5
4
5
12
6
7
16
7
8
20
7
8
25
8
9
30
8
9
35
8
9
40
9
10
45
9
10
60
9
10
65
9
10
70
9
10
80
10
11
90
10
11
100
10
11
125
10
11
150
10
11
175
10
11
200
10
11
300
10
11
400
11
13
500
11
13

The Project Sponsor may propose an alternative approach to determining sampling sizes, but it must be approved by CenterPoint Energy and be based on sound statistical principles.


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