Meeting the Stretch Energy Code
By Aliza Heeren, Marketing and High Performance Building Fellow
This January, the Massachusetts stretch energy code updated their energy efficiency standards from the 2009 International Energy Conservation Code (IECC) to the 2015 IECC, and the Center for EcoTechnology’s high performance building team is here to help you navigate the updates. These changes will require builders working in any of the 180 stretch code towns in Massachusetts to meet much stricter energy standards; such as reducing the envelope leakage down to 3.0 air changes per hour, and building an energy efficient home with a Home Energy (HERS) index that is 55 or less. To learn more about the specific changes in the new code, you can visit our blog or attend one of our energy code trainings. Once you have a grasp on the changes made, it’s time to start thinking about how you are going to meet the changes in your upcoming projects.
We spoke with one of our home energy raters, John Saveson, to learn more about his experience so far helping builders meet the new code. John commented, “recently I’ve had a couple of houses that are subject to the updated stretch code, and in both cases they are going to have to make some energy efficiency upgrades compared to what they thought they were going to be doing.” Building homes to comply with the new stretch energy code is going to be a stretch for any builder who is not already focusing on high efficiency. In the past two years alone, CET’s high performance building team has worked with about 65 homes that would not meet the new stretch code because their HERS index was above 55, and about 45 homes that would not meet it because they were over three air changes per hour.
John Saveson suggests a two part strategy for builders to reduce their HERS indexes to meet the energy code. First he suggests choosing one of the following three higher impact changes to make an initial dent in lowering your HERS index:
- Choosing a Heat Recovery Ventilator (HRV), which brings in fresh air while saving energy by transferring the heat and moisture from the outgoing air to the incoming air.
- Choosing to install insulated sheathing on the exterior of the building, beneath the siding to increase the insulation.
- Installing triple paned windows.
All three of these options will shave off three or four points from your HERS index, and will make passing the stretch energy code much more attainable. Secondly, John suggests pairing one of those options with a few lower hanging fruit that are less expensive, but will add up to achieve the HERS rating you are aiming for. Builders can work with their CET home energy rater to determine which combination of these and other options will bring the results they want within their time and price constraints. Some of John Saveson’s suggestions for smaller, yet impactful changes for lowering your HERS index are:
- Installing 100% energy efficient lighting: LEDs or compact fluorescent.
- Installing an ENERGY STAR washing machine (this can be 2 to 4 HERS index points!)
- Adding more loose blown cellulose into the attic.
- Installing a programmable thermostat.
- Upgrading the water heater to a more energy efficient model.
Recently, John worked with a builder on a single family home in a stretch code town whose initial HERS index was a 64. John suggested all of the above options, then helped the builder select the measures within his budget, resulting in the decision to implement triple paned windows, 100% efficient lighting, 18 inches of blown cellulose in the attic, and an ENERGY STAR washer. After working with John, the builder was able to get the HERS rating down to a 54! In addition, all builders will have to pay close attention to air sealing during construction to make sure they achieve no more than a leakage rate of 3 ACH50.