Deep Energy Retrofit in Belmont

In December 2008, my wife and I made a big decision: to downsize to a two-family house that we could share with my parents and renovate to be very energy efficient — a good move financially and environmentally and a good way to be close to family. We found a two-family near Cushing Square that seemed right — in good basic condition, but ready for some major renovation.

We are insulating the home to the highest practical standards in a retrofit — R-40 on the walls and R-60 on the roof. We have wrapped the whole house in foam panels and also blown cellulose into the wall cavities. The builder is installing new windows by cutting openings through the foam and sealing the windows onto the foam. The method will create a very tight house, with extremely low air infiltration. It will look like any other home eventually, but right now it looks like a big refrigerator — drive by 118-120 Gilbert Road.

With a super insulated house, one doesn’t need much heat. We knew we had to replace the big old oil burners (which powered steam radiators), but there were a lot of options to consider. In the end, we went with small efficient gas burners and a ducted hot air system. Onsite burning of gas appeared to be more efficient than electric heat pumps in the coldest winter months when we would be using heat most.

In a well sealed house, one needs to assure fresh air delivery with mechanical ventilation. We are installing heat recovery ventilators that will constantly bring in fresh air, but transfer energy from exhaust air so as to avoid heat loss. They will deliver air through the same ducts as the heating system.

We are looking forward to low heating and cooling costs and also to a greater comfort level in the house. The expectation is that the indoor environment will be both fresher and more stable.

Our builder identified for us a “Deep Energy Retrofit” grant offered by National Grid, the natural gas supplier for Belmont. National Grid offers substantial grants (up to $30,000 per unit; more for single family) in return for doing a project that meets their standards for energy efficiency and agreeing to be a guinea pig — installing monitoring equipment, being a training site for contractors and an education site for others considering similar projects.

When our builder began talking with National Grid, they pushed us to upgrade our insulation plan in several ways. National Grid works with excellent building scientists and having them involved has given us additional confidence that we are using the best available techniques. Click here for more information about the program. Their financial support will allow us to take the project one step further and install solar panels.

National Grid’s program is just getting started and they are looking for more people willing to make the investment. In our case, the available grants cover roughly one third of the cost of the energy components of the renovation (and none of the non-energy renovations). The personal investment is substantial and the payback period very long at current energy prices.

Although even with the available grants, the cost is high, we have found that downsizing and building green feels very right — lower carrying costs, lower taxes, lower energy bills, a sense of doing the right thing to cut our dependence on foreign energy. It also truly does bring family closer together in a good way. The project itself has been a great thing to share and we are looking forward to being together in the new home.

Note: This post originally published on April 23, 2010 was updated and expanded on May 23, 2010.

Published by Will Brownsberger

Will Brownsberger is State Senator from the Second Suffolk and Middlesex District.

3 replies on “Deep Energy Retrofit in Belmont”

  1. Hi Will,

    Your retrofit sounds very thorough, but I am wondering about it creating “a very tight house, with extremely low air infiltration”. It is my understanding that a certain amount of air filtration is good and keeps the indoor air healthier. Haven’t there been issues with extremely tight houses?

    I’m wondering it newer techniques address this.

    Sue Demb

    1. Good question.

      Part of the project is to change over the heating system to gas hot air. The old steam system is intrinsically inefficient. Radiators provide a more even heat in an old fashioned drafty house, but in a well insulated house, the heat feels even without all that iron in place.

      Using the same ducts as the hot air system, we will have a fresh air distribution system that will bring in fresh air over a heat exchanger so that we will always have fresh air but not be losing energy. For more on energy recovery ventilation, see Wikipedia.

  2. Hi Will,

    Congratulations on your deep energy retrofit! I’m so glad to be seeing more and more of these happening. I’m sure you’re aware there have been a couple in the area, particularly one here in Arlington that was also featured on Green Planet’s ‘Renovation Nation.’

    As an EcoBroker Realtor in Arlington, I am particularly interested in eco-friendly, sustainable living options and I frequently write posts about local green events, etc. I would like to ask if you would be willing to have me take a couple of pictures, or perhaps a short video of your project, to post on my blog site ( Please feel free to contact me at your convenience if you are willing.

    I’d also like to respond to Sue’s inquiry regarding the quality of indoor air when the home is sealed tightly. In short, it’s not a problem because proper sealing of the home includes maintaining proper ventilation. As long as you used a trained and certified contractor who’s experienced in home insulation and indoor air quality, you can’t go wrong. There’s also a detailed overview of indoor air quality, which you can find at the U.S. Health and Human Services web site: (

    Thanks again for undertaking this great project! I hope more and more homeowners will start to follow your example.

    -Tim Cahill

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