Why is my SIR so high or low? (or Why do I have high or low Energy Savings?)

Labels: energy model error message Heating and Cooling energy model input SIR

After performing an initial inspection and assignment of measures, occasionally an auditor will notice a very high SIR or very LOW SIR on the Energy Savings page.

 

You may also notice an error on the Modeling Report page: "Warning        The savings of Electric is larger than the current usage, please check the fuel usage on the Energy Consumption page."

 

Should this occur, please go to the Energy Savings Page and look for the Measure(s) which are higher than a typical 0-9 SIR.   See the highlighted example below.

 

 

Next review the total energy consumption numbers which have been entered for the job.

 

If the Modeled Pre-Usage and the Actual Pre-Usage are off by a large number, this typically reflects an error in data entry on the Client Intake > Energy Consumption screen or on the WAP > Audit Information Screen.

 

Common errors to check on high job energy savings:

  • Are either heating or cooling efficiency below 60%?

    This is the no. 1 reason our model will predict high savings, as heating and cooling efficiency effects most energy modeling components.

  • Are pre and post air infiltration (CFM) reduced by 3 cfm / sq ft or more?

    Common reductions in air infiltration are below 3 cfm /sq ft.

  • Did you select Duct System - existing condition - “catastrophic leaks”?

    Repairing catastrophic leaks for a large linear footage of duct work leads to high savings.

  • Did you double check Building dimensions and Section quantities in each sections?

    Double check dimensions are entered in feet. 

  • Look at pre r values of attic, wall, floor - The R-value in the attic and walls is entered as 0. If the house has no insulation, energy savings will be high.

  • When concrete slab is chosen on the floor section, the default R-value is very high, 41.66.

    Choosing "Slab" , then "Insulated Slab" defaults to an R-value of 2.52, which may be more reasonable.

  • For a Heating or Cooling System, what is the SEER for Pre- and Post replacement?

    If a Cooling system is selected to be replaced an the Pre- SEER is higher than the POST SEER, this will result in a SIR of 0.  The POST SIR should match the measure definition. 

To Correct these issues:

- Verify that the Client Intake > Energy Consumption numbers reflect the Client House Bills.

- Verify that the WAP > Audit Information Screen numbers reflect the house dimensions, and that the total sq feet calculation is reasonable.

- Review the energy audit screens for typos or incorrect data entry. There may be an incorrect quantity on a measure or incorrect size of a wall, attic or basement section.

- Review the Measures selected to make sure the Post efficiency or Post SEER matches the state default values. 

 

FAQs: When you have checked above, and still have High or Low or Zero savings...

1. Why does my DHW Pipe Insulation measure still have a high SIR? 

In some cases, pipe insulation can provide significant impact for a low cost.  Please check:
 
1.Measure Savings % is set to a reasonable number.  2.5% is the high end of an acceptable range 
2. Verify the Measure cost, if the cost is low, the SIR may reflect actual savings, especially in cases with an Electric Heat fuel source. Where there is a high cost of fuel, there is a higher lifetime energy savings.
 
2. Why does my Distribution Duct Sealing measure still have a high SIR? 
 
In some cases, repairing  "Significant Leaks" for Duct Leakage using  a low-cost Measure will result in significant savings.  This is especially true when the fuel is an Electric Heat fuel source (typically a high cost of fuel) and Ducts are used for both Heating & Cooling. 
 
3. Attic Insulation SIR is 0 Zero
Attic Insulation requires that the Attic screen has a Roof Material selected, Insulation Material Selected and a Measure that has Insulation value greater than the existing R Value.
The most common reason for a Zero 0 SIR on Attic is that the Roof Material is not selected on the Attic Section. Please select a Roof Material and click Save. 
Then on the Energy Savings report, please click Recalculate.
 
 
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