Commercial Connected Thermostats: Measure Lifetime Discussion

The purpose of this discussion thread is to obtain guidance on the handling of measure life in one version of the commercial connected thermostat measure we expect to propose at the March RTF meeting.  For a brief overview of this measure, see slides 24-28 of the RTF midpoint check-in presentation.  

This thread's topic is largely a matter of judgment, but it does have implications for how the CAT will arrange portions of the analysis and presentation.  For these reasons, the CAT hopes to have clear direction well in advance of the technical subcommittee meeting. (Slides 85-97 of the midpoint presentation provide an early indication of the topics we hope to discuss with the subcommittee.) 

The question is specific to the version of the thermostat measure that requires verification of efficient programming.  The program that requested this version plans to perform routine (e.g., annual) re-verification of efficient settings.  CAT has identified two potential approaches to measure life for this case.  We are interested in knowing whether commenters have a clear preference between these approaches.  If there is no clear preference, the CAT will default to Option A, Renewable 1-Year Measure Life. The approaches are as follows:

• A.  Renewable 1-Year Measure Life.  Measure life is 1 year, renewable up to 8* years.    

Example: The Planning UES (kWh/ton) is estimated as 10%* of typical annual HVAC kWh/ton for eligible building types.  This UES would be claimed for the initial year, and the same UES would be claimed again for each subsequent year (upon re-verification of efficient programming).   

• Pros:  Simple and provides a stronger incentive for programs to stay engaged with customers to maintain savings.
• Cons:  Not fully consistent with expectations for how the measure will work in the field: It is likely that initial installation would yield some savings for multiple years, and that programming verification would yield some incremental savings (see Option B).   

• B.  Device with multi-year measure life, plus incremental 1-yr savings for verified programming. 

Example:  The thermostat (device) installation has a Planning UES (kWh/ton) estimated as 4%* of typical annual HVAC kWh/ton for eligible building types, with a measure life of 5* years.  Verified efficient programming has a separate UES estimated as 6%* of typical annual HVAC kWh/ton with a 1-year measure life.  The 6%* programming UES would be claimed for the initial year and again for each subsequent year (upon re-verification).    

• Pros:  Consistent device-only version of the measure and with expectations for how the measure will work in the field.
• Cons:  Complicated, and provides a weaker incentive for programs to stay engaged with customers to maintain savings.

* Placeholder value included for the sake of this discussion. Parameter values in the proposal to the RTF will be informed by the technical subcommittee.