Somerville Voices

You can’t walk down the street nowadays without someone measuring your carbon footprint. But Somerville residents (who don’t drive much anyway) may be thinking that there isn’t much they’ll be able to do about it, assuming they’ve already screwed in all those compact fluorescents.

Pretty soon, though, the biggest contribution we can make as individuals may not be a Prius in the driveway. Instead, it’ll be a Honda in the basement.

Last year Climate Energy in Medfield ran a demonstration project in sixteen Massachusetts homes, replacing their gas-fired forced-hot-air heating systems with a new high-efficiency “freewatt” system featuring a Honda MCHP (Micro-CHP) unit. CHP stands for “Combined Heat and Power.” The unit is a small generator that takes advantage of heat thrown off generating electricity to provide a second home heating source.

The results were impressive. Using the same amount of gas (or in some cases a bit less), the homeowners were able to both heat their homes and dramatically cut their electrical bills. When home electrical use was low, the owners had the pleasure of actually seeing the electrical meter run backwards.

These savings for homeowners, though substantial, are dwarfed by the benefits for the environment. For every 100-watt lightbulb you burn, a power plant has to burn 290 watts of fuel to provide the electricity. The remaining 190 watts are being thrown into the environment in the form of waste heat. With a micro-CHP unit, however, that heat isn’t lost. A typical home that previously generated 4000 lbs of CO2 for winter electrical use can reduce it to 1000 lbs. That’s a substantial improvement on the energy savings from switching to a hybrid car.

Unlike some energy efficiencies, the new micro-CHP systems may actually make you more comfortable. The “freewatt” system is both quieter and cleaner than the standard forced hot air systems, and keeps the house at a more consistent temperature.

The new systems feature an internet tie-in that allows remote monitoring by Climate Energy, who are automatically flagged if any part of the system malfunctions. There is also an embedded web page that allows the owner to monitor the house, even if they are at work or away on vacation.

In Japan, 60,000 of these units have been installed in the last four years. The American version won a Breakthrough Technology Award for Home Energy from Popular Mechanics and CHP has been endorsed by the Sierra Club. But you don’t care about that. What you’re asking is how much does it cost. The answer is that it’ll cost you about $8,000 more than a standard new home furnace. Climate Energy estimates that it will take five to ten years for the systems to pay for themselves. They also point out that both the up-front costs and the payback period are much less than what you could hope for by investing in other home energy technologies like solar panels or ground-source heat pumps.

Climate Energy will be attending the Cambridge Energy Fair at Cambridge Rindge and Latin this Saturday from 10am to 2pm. Their traveling road show trailer has a working Warm Air freewatt System and a representative will be on hand to answer any questions. You can also check out www.freewatt.com. As you can tell, I’m pretty enthusiastic about it, and no, I have no financial interest in the company. Let me know what you think.