Ask the Energy Experts: How does demand-response affect controlled equipment?

Western customers use our Energy Experts hotline, 800-769-3756, to ask questions about how programs or technology works in a utility setting. Recently, we heard through the grapevine that some customers have been talking among themselves about a particular topic. We assume there are others wondering about the same things, so Energy Services Manager Ron Horstman posed the question to the Energy Experts:

I would like to know if utility demand-reduction (DR) programs that remotely control end-use water heaters and HVAC [heating, ventilation, air conditioning] systems could potentially damage that equipment or void manufacturers’ warranties. Also, do DR programs create distribution system voltage sags when a large number of appliances resume full operation at the same time?

Based on initial research and discussions with experts in the field, it appears that DR controls have minimal effect on equipment:

  • End-use equipment nearly always survives occasional power outages without serious damage, and power outages are much more severe and widespread than demand response programs.
  • A search of literature in the Energy Experts database revealed little documentation of this as an issue.
  • DR specialists at companies including energy data analyst E Source and energy management technology provider Comverge noted few if any reports of such problems. However, one cautioned that equipment owners do need to be aware of conditions that can void manufacturer’s warranties, such as restricting shut-off times to a minimum of five minutes.
  • Demand response control may increase or decrease the number of operation cycles—the number of times the equipment turns off and on—depending on the length of time during the DR event the customer agrees to allow interruption of operation. As long as the equipment has time to cool down between interruptions, the change in the number of operation cycles during a DR event represents a tiny percentage of the equipment’s annual cycles, so it is unlikely to “wear out” the system.
  • Because peak demand programs are a common and widespread load management strategy, manufacturers have designed their equipment to accommodate remotely controlled cycling.
  • “Smarter” grids bring more nuanced capability for equipment control.

Changing with times
Nevertheless, because many customers and some utility professionals continue to be concerned about the effects of DR on equipment, the issue is worth exploring further. DR control can range from an add-on Wi-Fi kit to a thermostat with additional useful features to a fully integrated appliance. Utilities find it challenging to interface with the wide variety of HVAC control system makes and models, but technology and experience are improving.

More and more manufacturers are offering equipment specifically designed to interact with peak demand control systems. This includes a control input on the device that allows utilities to easily connect it to a compatible DR communication module. These more sophisticated interfaces facilitate smoother load shedding, as well as load-shifting strategies like precooling a space or preheating a water tank in preparation for a peak-demand event.

Controlling air conditioners
The most common DR approach to HVAC equipment is controlling the condensing unit outside the building, so the supply fans continue to operate. The fan uses just a fraction of the energy of the compressor. Shutting the unit off by remotely setting back the thermostat is another simple control method.

On some equipment, the condenser and thermostat are not separately powered. Window air conditioners are one example, and these units account for 58 percent of air conditioning in the U.S., according to the U.S. Energy Information Administration. ThinkEco, a smart-control developer and provider, offers a Wi-Fi-connected Smart AC kit that is installed between the electrical outlet and the plug-in air conditioner. The company reports that the kit works with 90 percent of window air conditioners. On the remaining units, the compressor either did not come back on after power was restored, or came back on after several minutes.

ThinkEco and Carrier teamed up to integrate Carrier’s Comfort-choice thermostats and ThinkEco’s Modlet (modern outlet) cloud platform. This gives utilities access to real-time load data for window air conditioners and real-time demand-response control capabilities, while giving users control of all aspects of their air conditioner through their smart phone. Another ThinkEco partnership with Frigidaire integrated the same capability into a window air conditioner that retails for $270. New York City, which has the largest stock of window AC units in the U.S., offers a $125 rebate to residents for installing this air conditioner.

Motor issues
Electric motor damage is another concern for program managers and equipment owners. It is true that turning a motor on and off many times per hour without allowing time in between for cooling can damage the windings. However, in a demand response scenario, utilities don’t cycle controlled equipment that frequently. Customers can typically choose to have their equipment turned off 50, 75 or 100 percent of the time during peak events.

What about water heaters?
Regarding heat pump water heaters (HPWHs), a paper by the National Rural Electric Cooperative Association’s Cooperative Research Network compares the performance of HPWHs in a demand response scenario with an electric resistance water heater. “How Will Heat Pump Water Heaters Perform in Demand Response Programs” mentions the possibility of damage to compressors due to cycling and product warranty voids. Authors also suggest that the cost-effectiveness of using HPWHs in a DR program calls for more study.

The graph below indicates that HPWH energy use doesn’t peak nearly as much as electric resistance water heaters during typical times of utility peaking events, and they use considerably less energy. So the best solution to those possible issues may be to simply not include the systems in DR programs.


Water heater manufacturers have begun to include a port for grid connection using Modular Communications for Energy Management (CEA 2045), a common communications protocol established in 2013. Even before that, the Department of Energy found that some water heater manufacturers not only supported grid-connected appliances, but were already developing the devices.

Designing for unique customer
Industrial equipment requires a different approach to demand response. These customers use much more energy than residential or commercial customers, making them an attractive target when utilities need to shed a lot of load quickly. However, abruptly interrupting production can cost plants hundreds of thousands of dollars. Utilities must work with industrial facilities managers on an individual basis to minimize the effect of DR programs on operations.

Powering back up
Finally, there is not a significant risk of creating a distribution system voltage sag when the DR event ends and the utility brings the controlled loads back online. Although an AC motor can have inrush currents of six to eight times more than full load, utilities plan demand response to bring groups of customer loads offline and online in stages. The impact of restoring isolated equipment to a subset of customers and in stages is far less severe than restoring full power to all customers all at once after a power outage.

Ultimately, most HVAC and water heating equipment can handle demand response controls—either by power interruption or by on-site controls—without damage or voided warranty, as long as the interruption allows enough to allow the unit to cool down. Manufacturers typically specify a minimum time of five minutes.  A safer approach is controlling HVAC systems by setting back web-enabled thermostats, allowing the on-site control system to ramp down and ramp up in a normal way rather than by a sudden power interruption.

More resources

Around the web: Find qualified HVAC installation

An energy-efficient heating and cooling system can yield significant energy savings for home and business owners, as long as it is installed properly and that is the rub.HVACcontractor

Installation can make or break the system’s performance. Unfortunately, finding the right contractor—one experienced with today’s sophisticated, high-efficiency heating, ventilation and air conditioning (HVAC) equipment—is not easy, even in a big metropolitan area. Some utilities solve this problem by creating a trusted contractor pool to support their HVAC efficiency programs. You may not have the time or budget to do that, but you can introduce your customers to online resources to help them select the right person for their job.

Ask questions, look for credentials
Energy Star’s 10 Tips for Hiring a Heating and Cooling Contractor is a good place to start for basic common-sense advice. It includes a link to the Energy Star Guide to Energy Efficient Cooling and Heating, also available in Spanish. While your customers are on the website, they can research Energy Star-qualified heating and cooling equipment.

Air Conditioner Contractors of America (ACCA) has an outstanding page for homeowners You are leaving that discusses system maintenance, interviewing contractors, and even talks about Manual J, the industry standard for determining the size of an HVAC system. There are short, informative videos about the value of licensed contractors, questions to ask before hiring one and what to expect from a professional installation.

ACCA strongly recommends hiring a licensed contractor with technicians certified by North American Technician Excellence You are leaving (NATE). The nationally recognized, industry-supported certification organization has its own website with helpful Tips and Resources covering everything from safety to HVAC terminology. However, visitors should use the ACCA contractor locator to find local credentialed technicians as it is more up to date than the NATE database.

Building Performance Institute is another organization that certifies contractors and provides a searchable database. You are leaving The results include not only company location, but technician core certifications as well.

Visitors will find BPI’s contractor comparison form useful when getting estimates. The form lists 10 questions and space for the answers from three different contractors for easy comparison. It also lists the steps homeowners should expect during the installation process.

Be proactive
Homeowners generally don’t think about HVAC purchases and repairs—not exactly the stuff of daydreams, after all—until something goes wrong. Utilities can think ahead for their customers by creating a bill stuffer with contractor questions and links to online contractor finders. Make sure your customer service representatives have hard copies and electronic copies they can share with anyone who asks.

If you offer an incentive program for high-efficiency HVAC systems, place links to selected online resources on your program Web page. Make sure equipment vendors have copies of the contractor questions on hand to pass out with sales.

Educating customers about the value of hiring certified HVAC installers can create a ripple effect that motivates contractors in your service territory to seek certification. Utilities can be ready with information about credentialing organizations in case contractors call with questions. In a business where much of the training is passed from generation to generation, technicians in small towns and rural areas may not be aware of certification opportunities. If enough customers are asking about contractors’ credentials over time, you may find that your trusted contractor pool builds itself.

HVAC technologies highlighted in two April webinars

Learn about promising energy-efficient technologies for commercial heating, cooling and ventilation systems in a two-part webinar, You are leaving presented by Energy Efficiency Emerging Technologies (E3T) April 8 and April 15, 1 p.m. Mountain Time.

The April 8 webinar You are leaving focuses on commercial HVAC motors and fans. Expert speakers will discuss the advantages of electronically commutated permanent magnet (ECPM) motors driving fans and pumps, permanent magnet AC motors including Q-Sync, and high-volume, low-speed fan technology.

The topics of the April 15 webinar are variable refrigerant flow and variable-speed split system heat pumps.

Western co-sponsors the Emerging Technologies Showcase series with the Bonneville Power Administration. These monthly webinars present the latest information about promising energy-efficiency technologies and practices that BPA is considering for future research opportunities.

The webinars are free, but registration is required.  Contact E3T for more information. All webinars are recorded and available on the E3T website and ConduitYou are leaving

Hidden energy wasters hurt efficiency in commercial buildings

Controlling energy consumption in large commercial buildings can yield big rewards for both the owners and their power providers. Taking the long view, efficient buildings also contribute to the health of the occupants and the economy, too. So why are buildings still wasting as much as 50 percent of the energy that flows into them?

According to the Panoramic Power blog You are leaving, one of the culprits is secret energy wasters—building systems that are not maintained or used properly. The article cites studies that have shown how continuously monitoring and adjusting operations and implementing just a few energy-efficiency strategies can reduce a building’s energy use by as much as 30 percent.

Common—and often undetected—energy wasters include:

1. Lighting rooms where daylighting is sufficient: This can also cause the HVAC system to work harder, wasting more energy.

2. Systems that continue operate after business hours: It’s 7 p.m. Do you know if your lights and HVAC systems are still on?   

3. Performing unnecessary maintenance: Working on a system that doesn’t need maintenance can actually be an energy drain. Build your maintenance schedules around performance data to promote energy efficiency, reduce downtime and improve overall performance.

4. Running equipment that is not in use: If the device has a built-in power management feature that automatically induces sleep cycles when it is not being used, make sure the feature is activated. Check into “smart” monitors and power strips to control older devices that do not have built-in power management.

5. Heating against cooling: An over-cooled office may cause employees to run space heaters under their desks, causing a vicious circle of energy waste.

6. Overlighting: More is not always better when it comes to lighting. Use resources from the Illuminating Engineering Society You are leaving to determine the appropriate lighting levels for your needs.

7. Insulation is not forever: Schedule periodic inspections of all piping, ducting and equipment to look for damaged or degraded insulation and possible energy leaks.

8. Filthy filters: Clean and replace filters on HVAC equipment frequently during high-use periods. Dirty filters are an expensive mistake, and lead to poor indoor air quality, too.

9. Blocked vents: A chair or file cabinet blocking a vent can cause your ventilation system to use as much as 25 percent more energy to distribute air.

10. Overriding Building Management System settings: Everything works better if you use it as intended. When occupants override the building’s automated controls—for a weekend meeting, for example—energy waste is quick to follow.

Some of these energy wasters can be stopped with simple, low-tech solutions like opening blinds during the day and regularly replacing filters. Other systems will require more advanced monitoring, data analysis or even recommissioning to correct. Even if you have a building energy manager, a consultation with a certified technician may be worth the investment.

Key account managers should keep a checklist of best practices for stamping out energy waste close at hand to share with commercial customers. Ultimately, it is crucial to remind building owners that monitoring all the energy-consuming equipment and systems in the building is the best way to catch and stop energy waste before it shows up in a large utility bill.

Source: Panoramic Power blog, 1/17/15

Announcing the Advanced RTU Campaign

Older, inefficient commercial HVAC rooftop unit (RTU) air conditioning systems can significantly add to a building’s energy costs, and these Energy Hogs are everywhere.  Luckily, several high-efficiency options are available for replacing or retrofitting RTUs that can save money and energy, make your building more comfortable and help the environment. 

The Advanced RTU Campaign (ARC) encourages commercial building owners and operators to evaluate their stock of RTUs and replace older units with high-efficiency ones. Retrofitting newer RTUs with advanced controls can improve their performance as well.  The campaign is a collaboration between ASHRAE, the Retail Industry Leaders Association (RILA), the Department of Energy (DOE) Better Buildings Alliance and several supporting organizations to help speed widespread adoption of these efficient solutions.  Read more about ARC and to join.

ARC provides building owners and operators with information and expertise to lower facility operating costs while maintaining or improving building occupant comfort.  To join the campaign, make a pledge to evaluate opportunities for incredible savings. Participants will be able to:

  • Leverage campaign resources and technical expertise in evaluating savings opportunities
  • Stay informed on innovative RTU technologies and resources produced through the campaign
  • Gain recognition, achievement awards and participate in case studies (pending submitting documentation of implementing a replacement or retrofit)

Organizations that promote high-efficiency RTU technology and best practices (utilities, manufacturers, contractors, etc.) can also join the campaign as supporters.  Supporters are organizations that promote resources, equipment or incentives for replacements and retrofits.  They can be a part of the campaign to help recruit their members or customers to join the campaign and take advantage of its resources.

Emerging Technologies webinar series continues

Variable Refrigerant Flow
Nov. 14, 12-1:00 p.m. PST

Join Western and the Washington State University (WSU) Energy Program Redirecting to a non-government site for the fourth in a series of five “Emerging Technologies Showcase” webinars. Variable Refrigerant Flow, or VRF, is an HVAC technology that provides energy-efficient heating and cooling across multiple zones. The webinar will cover a technology and application overview and case studies, followed by a question-and-answer session.

This Showcase series of monthly webinars brings you the latest information about some of the promising energy efficiency technologies and practices that Bonneville Power Administration (BPA) is considering for future research opportunities or focus areas.

The Energy Efficiency Emerging Technologies (E3T) program Redirecting to a non-government site is an ongoing collaborative effort involving BPA, WSU Energy Program, Northwest Energy Efficiency Alliance Redirecting to a non-government site and national experts to identify, assess, and disseminate innovative, highly-valued energy efficiency strategies and technologies that promise significant region-wide energy savings.

Register now Redirecting to a non-government site. All webinars will be recorded and available on the E3T website, and Conduit Redirecting to a non-government site, an energy-efficiency forum.

Select HVAC Joint Program Implementation

Gary Myers, Poudre Valley REA, and Mike Rubala, Platte River Power Authority

One of the biggest energy-related problems for utility customers and contractors is HVAC. The goals of the Select HVAC program is to “stop the madness” of poor installation, and to develop a list of competent HVAC contractors within legal bounds.

When the utility receives a call from a customer with an HVAC complaint, it may be about a high bill or air quality, safety concerns or poor performance. An inspector visits the customer and often discovers alarming problems. Systems are poorly designed and haven’t been commissioned. The ductwork may be improperly designed or disconnected or the installer failed to test the system. Sometimes there is no filter.

There are operational problems, too. Homeowners haven’t been properly instructed in how to use the programmable thermostat, or they have not been told how to maintain or service the unit.

It’s time to demand contractors adhere to industry required standards. HVAC systems are complex, and contactors must understand many factors. To be a Select contractor, the contractor must hold all the necessary licenses, maintain proper insurance, comply with program code of ethics, hold any pertinent certifications required by Poudre Valley and Platte River, do proper commissioning and agree to third party inspections.

Initially, the utilities sent invitation to 101 contractors, but only 12 responded—about 10 percent of the contractors are “sane.” To play ball, they have to sign several agreements. Front Range Community College is conducting required training. The college has an established HVAC program.

The customers now have access to reliable contractors, and the contractors get referrals. The program is also promoted on the utilities’ websites, in bill stuffers, city newsletters and newspaper ads. The magazine Colorado Country Life carries ads for the program that the contractors couldn’t afford on their own.

The program is increasing professionalism among the participating contractors. Contractors are able to charge more for a better job, and customers trust the work. No one has dropped out of the program.