In-Home Energy Use Displays
Premise Level Information: Low-Cost Energy Monitors with Real-time and Historic Data vs. Monthly Energy Bills
Provide real-time and historic energy use information in homes and businesses to encourage conservation.
Synopsis:
Low-cost monitoring systems are widely available, and offer real-time energy use displays, record energy use, allow for easy analysis and make this information available over the Internet to allow remote access to energy use data. Real-time monitors allow homeowners to identify loads that can be switched off when space is unoccupied or equipment use is unnecessary. Some equipment vendors offer subscriptions to a cloud-based service where subscribers can view energy use and cost trends.
Energy savings increase when real-time monitors are coupled with historic information, which allowed users to analyze their energy use over time and support decisions to replace older appliances with more energy-efficient models. Landlords can monitor energy use in rentals, which can be critical if they are paying the energy bill or trying to allocate energy use among several apartments that are under one utility meter. Business owners can monitor energy use in several locations and shut off heating and cooling vacant space.
Available systems cost less than $200 per site and can be coupled with an Internet system that allows graphing and downloading of energy use at many remote sites and from multiple meters or circuits at those sites. These systems provide whole-house, near real-time energy consumption and cost information often viewable in seconds, minutes, hours, days, or months. To promote customer engagement, some units are designed to glow in different colors based upon rate of energy use. Behavior change is encouraged through social comparisons, goal settings, making personal comparisons or trending available, and establishment of action steps. Effectiveness is strongly dependent upon design of the display and its applications. ACEEE has conducted a "meta-study" and finds that real-time or direct feedback of premise level information results in household energy savings of 9.2% (Ehrhardt-Martinez, 2010 Pg iii)
Energy Savings: 9%
Energy Savings Rating: Extensive Assessment
What's this?
| Level | Status | Description |
| 1 | Concept not validated | Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts. |
| 2 | Concept validated: | An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles. |
| 3 | Limited assessment | An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline. |
| 4 | Extensive assessment | Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
| 5 | Comprehensive analysis | Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications. |
| 6 | Approved measure | Protocols for technology application are established and approved. |
Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:
Simple Payback = Incremental First Cost / Annual Savings
The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.
For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.
For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.
Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.
The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.