SAN FRANCISCO -- A Virginia startup is launching a monitoring system that it says will not only enable homeowners keep track of the performance of their solar water heaters but also help states craft more effective incentives for installing those systems.
Sunnovations has developed a sensor and software for residential solar water heating systems. Homeowners can check on the amount of thermal energy produced and use on an online dashboard, which, by typing in the rates their utilities charge for fuels to heat water, will also show much money they are saving.
The savings reflect the difference between using fuels — oil, natural gas or electricity — from utilities and using solar energy to produce hot water. The figures aren't meant to show the returns on investing in a solar water heater and monitoring system.
"You as a homeowner would want to know if your solar hot water system is functioning properly," said Matt Carlson, CEO of Sunnovations. "You have made an investment that is not trivial."
The monitoring system (see video) is the first for Sunnovations, which started in 2008 to develop solar water heating systems. The company launched its very first solar water heating product in 2010 and raised an undisclosed Series A round in 2011. The startup has raised a total of $1.5 million in venture capital since its inception, including the $500,000 it lined up last year, Carlson said.
The company is part of a crop of startups that have sprung up in recent years to take advantage of federal and state incentives for installing solar heating systems. The federal government offers a 30 percent tax credit on the price of installing solar water heating equipment. State subsidies vary and usually involve rebates.
Many incentive programs provide incentive for installing the equipment rather than for the performance of the systems. As a result, they don't require monitoring to determine the subsidy amount. California's residential solar water heating program has a monitoring requirement only for systems that serve multifamily housing. For a single family home, the amount of incentive is based on an estimated amount of therms or kilowatt hours that the solar water heating can displace each year.
Businesses that use solar water heating systems tend to buy monitoring gear as well even if they aren't required to do so to claim incentives. Those heating systems tend to be larger and cost more, so business owners want to make sure the equipment is performing well and giving them the savings they expect.
Some states are looking at requiring monitoring for their residential solar water heating programs. New Hampshire wants to craft rules for monitoring but has found the task difficult mainly because there isn't an industry-wide technical standard for measuring solar thermal energy, said Chris Williams, chief marketing officer for Michigan-based HeatSpring Learning Institute, which offers training and education to companies that design and install solar electric and thermal systems, as well as geothermal pumps. Williams also is an advisor for Ground Energy Support, which sells monitoring equipment and services for geothermal heat pumps. The American Society of Testing Materials is working on a standard.
Many monitoring systems on the market today use sensors to measure the temperatures and flow rate of the heating fluid as it moves through pipes inside solar thermal panels before brining that heat to a tank of water, Carlson said. Those measurements are used to calculate how much heat goes moves to the water tank, but they don't always do a good job of determining the amount of thermal energy that ends up inside the tank, he said.
Some of the monitoring systems also suffer from high failure rates because of their poor design or installation and operational errors, according to a study by the Orlando Municipal Utility in Florida last year. A separate 2012 report by the Massachusetts Clean Energy Commission showed that a monitoring system in the state typically costs over $1,000 and accounts for as much as 15 percent of the price of a solar water heating system. Across the country, a residential solar water heating system generally costs between $5,000 and $10,000, Carlson said.
Sunnovations' sensor is plugged into a port that comes standard in water heaters. The sensor measures the resistance to the low current that runs through it and in the process it's able to determine whether the thermal energy going into the tank comes from the solar collectors or from the electricity or other conventional fuels, Carlson said. The sensor also can measure the amount of energy that flows out of the tank and being used by residents of the home. The measurements show up online in kilowatt-hours because consumers are more familiar with that metrics than with BTU, which is a more conventional way to measure thermal energy.
Sunnovations is pricing its monitoring system at $499, which is cheaper than some of the competitors' products, Carlson said. The startup is selling the monitoring package on its website. Delivery of the monitoring tool will start in May.
Sunnovations is up against monitoring equipment makers such as Steca, Resol and Sunreports.