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Jesse is a researcher, consultant, and writer with ten years of experience in the energy sector and expertise in electric power systems, electricity regulation, energy and climate change policy...

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Can Radiator Labs's Cozy Bring Steam Heat into the 21st Century?

After Google’s $3.2 billion acquisition of Nest Labs, thermostats are suddenly sexy and all eyes are on the fast-growing home energy management market.

Yet as a tenant of a pre-war New England apartment building, I’ve watched with envy as startups and established companies alike launch innovative new products allowing owners to retrofit their homes for maximum efficiency, comfort, and control.

Sure, I’ve installed a few LED lights, set my window-mounted AC unit on eco-mode during the summer, and try to daylight our rooms as much as possible. But I don’t even have a thermostat, let alone a Nest Learning Thermostat! With ancient steam radiators and a gas-fired boiler controlled by our building owner, there’s very little I can do to control my energy use during the winter months—precisely when my energy bill is at its highest.

It turns out I’m not alone. About 1 in 10 homes and apartments in the United States and 3 in 10 commercial spaces are heated by steam or hot water systems, with at least half of that housing stock reliant on steam radiator heat just like my building. In old, dense cities across the northeastern United States, steam heat is often one of the dominant forms of home heating.

These steam systems are notoriously difficult to control and can be enormously wasteful. Walk down the streets of New York or Boston in December and you’ll probably see half the apartment windows open, venting hot air and wasting energy and money. NYSERDA estimates that $4.5 billion worth of fuel oil and gas is wasted annually to overheat apartments.  

State laws generally require building owners to maintain minimum temperatures for tenants, meaning, by statute, every boiler has to cater to the coldest unit in the complex. That means most of the units in the building are overheated, and there’s little the building manager can do about it.

Since the radiator in your apartment usually has just two settings — fully on or fully off! — opening the windows has been the only real way tenants can control the comfort of their apartments… until now! 

Radiator Labs, a New York-based startup, is on a mission to bring steam heat into the 21st century.

The company builds and markets a slick, affordable, and easy to install system, called the Cozy, that finally gives tenants of steam-heated buildings control over the temperature of your home. 

“Steam heat sucks,” Marshall Cox, CEO and founder of Radiator Labs, told me in an interview for And his company is out to change that.

“Systems have tried to solve these problems before,” Cox said. “TRVs [thermostatic radiator valves] replace the valve on your radiator with a dial that goes from 1-9 or something and allegedly gives you more control. These work for hot water systems, sometimes, but not for steam.”

“Steam is really hard to control,” Cox explained. “It’s a two-phase system, and steam is really caustic, so these things [TRVs] typically break within a couple of years. As a result, they never really pay for themselves in energy savings before they break on you.”

So Radiator Labs tried a totally different approach.

“Instead of controlling the steam flow into your radiator, our system controls the air around the radiator,” said Cox.

Radiator Labs’s elegantly simple system involves an insulated cover, which fully encloses your radiator, and a thermostatically controlled fan, which only transfers heat into your room when you want it.

Radiator Labs CozyRadiator Labs’s Cozy lets buidings with steam heat join the home energy management revolution

Installed in a single apartment, Radiator Labs’s Cozy helps those of us dependent on steam heat finally join the home energy management revolution. The system gives the occupant control over their comfort and the company is developing a mobile app to allow users to wirelessly set the thermostat conditions that control the fan. The consumer product will use WiFi to connect to your home router and join the “Internet of things.”

Radiator Labs also offers full building installations, which outfit every unit in the building with radiator enclosure systems controlled via a wireless mesh network built on Zigbee’s low-power digital radio platform. Each radiator system communicates with the central boiler, telling it when apartment tenants are really demanding more heat, and allowing the boiler to operate less frequently. The result: savings of up to 30 percent of the building’s energy costs, according to company estimates.

Both systems work the same basic way.

“When the fan is off, inside the enclosure, it heats up fast,” Cox explains. “Once it hits 100 degrees Celsius, no more steam can condense inside the radiator. So instead of dumping energy into that radiator, the energy moves into another pipe and off to another unit in the building.”

That’s why full building installations are key to unlocking the full energy savings potential of Radiator Lab’s invention. If just one unit in the complex installs the Cozy radiator cover, the owner of that unit will get complete control over their own temperature, but they’ll end up shunting heat through the steam pipes into other units in the complex, where it will likely escape through another open window. That won’t change overall building energy use much.

By contrast, if the full building installs Radiator Lab’s system, the heat will stay trapped in the steam system until the boiler’s thermostat shuts it off. The boiler will only turn on when tenants really need the heat, and no more fuel will be wasted overheating apartments.

“If you get 1 out of 100 units in a building using our system, you may get 1 percent energy savings,” estimates Cox. “But if you get 80 out of 100 units, you probably get most of the savings you’d get if you had all 100 units.”

To get their systems installed in more buildings and unlock the energy and environmental potential, the Columbia University spinout launched a Kickstarter this week to crowdsource $100,000 to produce the consumer version of their product. The video below explains Radiator Lab’s Cozy and the goals of the Kickstarter.

(Check out the Radiator Labs Kickstarter page for more videos and info explaining how the Cozy works and more…)

“The goal of this Kickstarter is to make the Cozy easy to install and adopt, attractive to consumers, and allow this to really scale,” Cox told me. “And we can then use this new consumer model to build out full building installations as well and make a strong financial case to building owners.”

“We know we can fix the comfort and control problem now, so we want to get this out to consumers,” Cox says. “The next step is to prove we can save energy and money for full building installs.”

Cox started the company while finishing his PhD in Electrical Engineering at Columbia University. He lived with his twin brother in an overheated New York City apartment and fashioned the first prototype to give them some control over their antiquated steam radiators.

Columbia later provided some startup funds to test out a more refined system in some of the residence halls on campus, proving that the system could deliver real improvements in comfort.

After winning first prize and $220,000 in the MIT Clean Energy Prize competition in 2012, Cox and his team used those funds to develop their first commercial product.

The key design challenge: every radiator is a different size.

“Some of the radiators still in use today were produced by hand in foundries in the 1920s,” Cox lamented.

Almost every radiator the company encountered during their initial installations was different, Cox said. “For that reason, every single one of our enclosures at the start was custom made with the fabric sowed to order at a factory in upstate New York.”

After installing a number of full building installations using these customized systems, Cox and his team went back to the drawing board to come up with a commercial product that could really scale.

The result: a folded fabric design with just a few different starting sizes, two halves that telescope over the radiator addressing the large variations in their length, and the ability to fold out the seams to expand in width as well.

Funds from the Kickstarter will allow Radiator Labs to begin larger-scale production of this new mass-producible system.

The Radiator Lab’s Cozy will be produced entirely in the United States, except for the fans, which Cox says proved too difficult to source from the U.S. The specially designed insulated fabrics are woven and sown in upstate New York and the final product is assembled in Brooklyn.

“A lot of Kickstarters have suffered from an inability to actually manufacture their product,” Cox told me. “But we’ve done this before. We have two years of experience manufacturing the custom product for full building installations. We already have our supplier relationships.”

Radiator Labs launched its Kickstarter this week and aims to raise funds for an October 2014 product launch.

“That will allow us to deliver product before the next heating system,” Cox says.

“We’ve already done two design iterations and have delivered on time,” assures the CEO.

Head here to check out the Kickstarter campaign and to the company’s website and to learn more about their product. 

You can also watch Marshall explain the Radiator Labs system below, in a video produced for a 2012 Department of Energy National Clean Energy Business Plan Competition

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