New Column: Stay Warm, Stay Green

This is a new feature, an energy advice column from the Energy Coordinating Agency (ECA). Our goal is to answer any and all questions about energy issues in your home or other buildings. We have experts available to answer whatever you throw at us. Energy issues might include how to save energy in buildings or how to utilize renewable energy resources, but can also extend to a boiler issue or a perplexing moisture problem. Whatever it is, send in your question and we will try to provide the most comprehensive answer possible.

Sealing places where air flows will increase the benefits of insulation.

ECA is a local non-profit with 24 years of experience in energy conservation issues. Our mission is to help people conserve energy and to promote a sustainable and socially equitable energy future for all. ECA received the 2008 ENERGY STAR Leadership in Housing Award from the U.S. EPA for our ENERGY STAR work in affordable housing.

Stop the air war!


Q: Since winter is here and my heating bills are too high, I was planning on adding some insulation. A friend of mine told me that insulation wouldn’t help if I didn’t air seal first. What is air sealing, and why is it important to air seal before I insulate?

A:   Heat leaves a house by two means: Conduction and Convection.  Conduction is when heat energy passes through materials from warm areas to cold, and this can be reduced by adding insulation.  Convection is the movement of air carrying heat away - this can be reduced by draft-blocking or air-sealing. Here is a graphic of how air-sealing affects a house.

All types of insulation are more effective if air movement through and around the house is reduced or eliminated.  This is where air-sealing comes in.  Air-sealing with caulk or weatherstripping should be done in obvious areas, such as window and door jambs and wall penetrations for pipes and wires; but it also needs to be done in not-so-obvious places behind walls and ceilings, to keep air from moving inside insulated cavities and through attic insulation. 

You may get some benefit from just adding insulation to your home, but you will get maximum benefit only if you air-seal first, then insulate.  Make sure any insulation contractor you hire knows how to properly air-seal.  If you are doing it yourself, check the Energy Star website for publications on air-sealing.

Let it bleed

Q: I live in a row home in South Philadelphia. When I turn the heat on in my house the first two floors get warm, but the third floor is icy cold, even when I turn the thermostat up. I have all the windows closed, but it feels almost like I am outside! Why is this, and what can I do to fix it?

A:  There could be many reasons why temperatures vary from room to room in a house, but the uneven distribution of heat is an obvious place to start.  If you have radiators, check for heat at each radiator when the heating system is in operation.

If your home has hot water heat, the radiators on the top floor may have become “air-bound.”  Water naturally contains some dissolved air.  When the water is heated, this air can come out of solution in the places where the water pressure is the lowest, such as the upper floors of a house, and collect in the radiators.  The collected air blocks the water flow through those radiators. 

Use a screwdriver or radiator key to open the bleeder valve on the side of the radiator.  If air comes out, let the air escape until water squirts out. If nothing comes out, it means the system does not have enough pressure. Go to the basement and find the water fill valve. Add water to the system until the gauge on the heating unit reads 12 to 20 psi.  A three-story house will need more pressure than a single or two-story house.  Finish bleeding the air out of all radiators, then go back to the heating unit and check that the pressure has not fallen too far. 

If this doesn’t fix your distribution problem, you may need to call a professional to do additional diagnostics. See for more information.

Got an energy question? Send it in to and watch for an answer in an upcoming edition of Stay Warm, Stay Green.

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