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Residential Electronic Line Voltage Thermostats

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Work Products

UES Measures Standard protocols list Demand Response Technologies Supporting Documents Propose a measure or standard protocol Proposed measures and status Whole Building Efforts

Subcommittees

  • Agricultural Irrigation
  • Air Source Heat Pumps
  • Commercial HVAC
  • Compressed Air
  • Connected Thermostats
  • Demand Response
  • Ductless Heat Pumps
  • Duct Sealing
  • Guidelines
  • Heat Pump Water Heaters
  • Implementers Group
  • Market Analysis
  • Natural Gas Subcommittee
  • New Homes Standard Protocol
  • Non-Residential Lighting
  • Operations
  • Pump Systems
  • Research and Evaluation
  • Residential Behavior
  • Residential Lighting
  • RTF Policy Advisory Committee
  • Small and Rural Utilities
  • Statistical Methods
  • Whole Building Subcommittee
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UES Measure

  • Residential Electronic Line Voltage Thermostats

Residential Electronic Line Voltage Thermostats

At a Glance

Status 
active
Fuel type 
electric
Sector 
residential
Applications 
HVAC
Sunset date 
Apr 30, 2025

Line voltage thermostats are installed in a series with a single stage conditioning system on a 120V or 240V line. Electricity flows through the thermostat to the system allowing the thermostat to complete or break the circuit based on room temperature. Typically they control a zonal heating system, but can occasionally control a central electric furnace.  This measure specifies two thermostat types Electronic Line Voltage Thermostats (ELVTs) and Line Voltage Communicating Thermostats (LVCTs). 

There are a few ways ELVTs and LVCTs could save energy, though these savings are not confirmed and the measure is planning. All ELVTs may reduce deadband and reduce drop while some offer programmability.  LCVTs could save energy through connectivity and on-board occupancy sensors or geofencing, though the later is not incorporated into into proposed savings estimate due to lack of data. 

This measure is Planning. The proposed research strategy aims to estimate savings as a percent of total heating energy for whole-building thermostat change-out in homes with electric resistance zonal heat, determine the average number of thermostats installed in homes with electric resistance zonal heat, and survey retail purchasers of ELVTs/LVCTs to determine the current practice mix and installation practices.       

Workbook

Latest Version

Residential Electronic Line Voltage Thermostats v5.2

File Residential Electronic Line Voltage Thermostats v5.2
Approved at the April 2022 RTF meeting. QC complete.
Date 
Jun 14, 2022
Version number 
5.2

Past Versions

version date document
5.1
Apr 28, 2022
File Residential Electronic Line Voltage Thermostat v5.1
Approved at the April 2022 RTF meeting. Updated post meeting, at the direction of the RTF, to include DI versus Retail in the specification as appropriate. Currently undergoing QC.
4.2
Oct 05, 2021
File Residential Electronic Line Voltage Thermostats v4.2
This version has been updated to provide additional clarity regarding the specification for the LVCT measure identifier.
4.1
Jul 08, 2019
File Residential Electronic Line Voltage Thermostat v4.1
Measure as approved by the RTF at the April 2019 meeting. QA/QC complete. Costs decreased by ~20% for the "any" measure applications.
4.0
May 16, 2019
File Residential Electronic Line Voltage Thermostats
Currently undergoing QA/QC.
3.1
Nov 17, 2016
File ResSFElectronicTStats_v3_1.xlsm
QC Complete. Converted to 7Plan format and assumptions.
3.0
Apr 29, 2016
File ResSFElectronicTStats_v3.xlsm
Currently Undergoing QC
2.1
Jan 04, 2016
File ResSFElectronicTStats_v2_1.xlsm
Delivery verification checklist added
2.0
Jul 12, 2011
File ResSFElectronicTStats_v2_0.xlsm
Updated as per recommendation memo.
Supporting Documents
File Electronic Line Voltage Thermostats-Research Strategy(April 2019)
File RBSA VBDD Outputs (2018)

Decisions

Expand All Decisions

Latest decision

Decision details

Decided 
April 19, 2022
RTF Meeting: April 19-20 2022

Approve Measure Updates

Decision Details

Update the Residential Line Voltage Thermostats measure as presented and:

  • Keep the Status at Active
  • Keep the Category at Planning
  • Update specification to include DI versus Retail as appropriate 
  • Set the Sunset Date to April 30, 2025
Notes on changes:
  • Savings went slightly down for LVCTs and stayed the same for ELVTs
  • Cost effectiveness went down for all applications: -Reduction is due primarily to change in calculation of capacity benefits and reduction in the value of energy from the 2021 Plan -No LVCTs are considered cost effective, a few ELVTs remain so
Decided 
April 23, 2019
RTF Meeting: April 23, 2019

Approve Measure Updates

Decision Details

Adopt the updates to the Residential Electronic Thermostats measure as presented:

  • Keep the Status as Active
  • Keep the Category at Planning
  • Change the assumed number of retrofitted thermostats per home to 5 for SF and 3 for MF
  • Assume that DHP/Hybrid applications have one fewer thermostat per home retrofitted
  • Use both RBSA I and RBSA II by heating zone and heating system type in calculating heating consumption
  • Change the Measure Name to 'Residential Electronic Line Voltage Thermostats'
  • Set the Sunset Date to April 30, 2022. 
Decided 
April 19, 2016
RTF Meeting: April 19, 2016

Approve measure update

Decision Details
  • Make the proposed changes and additions to the Residential Line Voltage Electronic Thermostat Measure, including:
    • Update measure specifications
    • Update measure savings 
    • Adopt the proposed Research Strategies---Modified to understand where retail-sold thermostats land (DHP, zonal, SF, MF, commercial)---Also understand what type of thermostat they're replacing 
  • Change the Category to 'Planning' 
  • Keep the Status at 'Active'
  • Set the sunset date to April 2019,
  • Develop a retail planning measure:
    • Use SF savings for retail applications, derated 10% to account for DHP installations
Decided 
November 10, 2015
RTF Meeting: November 10, 2015

Approve measure update

Decision Details

Adopt the delivery verification guidance as presented for the following measures:

  • Com Grocery – Display Case LEDs (Open Cases)
  • Com Grocery – Display Case Motion Sensors
  • Com Grocery – Floating Head Pressure Controls for Single Compressor Systems
  • Com Grocery – Strip Curtains
  • Com Grocery – Walk-in Evaporator Fan EC Motor Controllers
  • Com Grocery – Compressor Head Fan Motor Retrofit to EC Motor
  • Com Smart Plug Power Strips• Com Traffic Signals – LED Traffic Signals
  • Res Heating/Cooling – Electronic Thermostats
  • Res Heating/Cooling – Ground Source Heat Pump Upgrades
  • Res Lighting – High Performance T8 Lamps (4 foot and 8 foot).
Decided 
May 03, 2011
RTF Meeting: May 3, 2011

Approve measure updates

Decision Details

Approved UES values and costs for the line voltage thermostat measure. This is approved as an active measure.

Decided 
February 01, 2011
RTF Meeting: February 1, 2011

Set measure to Under Review

Decision Details

The RTF moved the status of this measure to "under review."

Small/rural Checklist

Latest Version

Residential Electronic Line Voltage Thermostats Small/Rural Checklist

File Residential Electronic Line Voltage Thermostats Small/Rural Checklist
Date 
Apr 29, 2016
Version number 
3.0

Archived Documents

Archived Documents

Archived Documents

Electronic Line Voltage Thermostats-Primary Research Strategy (2016) Electric Line Voltage Thermostats-Retail Research Strategy (2016) Electronic Line Voltage Thermostats Specifications v2.0 (2009) Electronic Line Voltage Thermostats Recommendations (2010)

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