Building Code Update | Survey Results + More!

Thank you to many of you who responded to our survey which was intended to get feedback on our Air Tight News newsletter.  We received a very good response. About 48% said they thought the Energy Code was easy to understand while the remaining 52% said no or had difficulty understanding parts of it.

We are happy to see that about 57% found the newsletter relevant to their work. Another 33% said they haven’t had time to read it. No surprise there. Also, most people in the industry learn about the code and Mass Save program from friends and contacts in the industry.

When asked in the survey what topics would you like to have covered in the newsletter, the responses covered a broad range of subject matter from understanding the code to construction techniques to documentation and so on. We will cover all topics in upcoming newsletters and we will have a link to previous months.

Ventilation is an area where many questions were asked. Mechanical ventilation is now a code requirement most commonly met with a timed or continuously running bath fan. One particularly good question from the survey was: what are the benefits of Heat Recovery/Energy Recovery (ERV/HRV) ventilation units versus bath fans?

First and foremost, an HRV/ERV system should provide better indoor air quality and healthier, more comfortable living conditions than a bath fan. Secondly, an HRV/ERV helps significantly to get a better HERS Rating and meet code. This is because the energy model accounts for conditioned air that is brought in through the HRV/ERV versus 100% unconditioned air assumed to be introduced by a bath fan.

Other benefits of an HRV/ERV versus a bath fan are durability and potentially increased home value. An HRV/ERV provides substantially more control over ventilation than a bathroom fan. Thus, there is better moisture control that could affect durability which can affect resale value as well comfort as a selling feature. Obviously, HRV/ERV systems cost more than bath fans, but keeping the design simple with an HRV/ERV is strongly recommended. This should help keep the cost down.

Many wanted to know what the main items are that need to be addresses in order to meet the new code of HERS 55. Every house is different, but a good check list with which to start is as follows:

• Furnaces – Should be 95% or higher.
• Water Heater – On demand (no storage) or hybrid if storage is best.
• 3 Air Changes per hour or less using blower door is a must.
• Air ducts at 4% leakage of below is a must.
• Energy Star appliances.
• Consider low-cost basement conditioning option.
• Consider HRV/ERV.
• Insulate on-grade slabs to code including at walk-outs and to garage.

As mentioned above, the list serves only as a guide to get started. There are many factors that can affect the HERS Rating for a given home. And paying attention to design and construction details is critical.

The Harvard Center for Green Buildings and Cities (CGBC) has revealed its centerpiece initiative: an ambitious retrofit of its Cambridge headquarters, a pre-1940s, stick-built house into a prototype of ultra-efficiency. Named the “HouseZero” project, this initiative represents several years of intensive research and a comprehensive redesign, developed with Snøhetta. Read . FastCompany‘s feature on the HouseZero project. As the CGBC notes, the procedure and mission underlying HouseZero, while wide-ranging, will be accomplished using existing technology that homeowners can purchase now.

“Before now, this level of efficiency could only be achieved in new construction,” says Ali Malkawi, professor of architectural technology at the GSD, founding director of the Harvard Center for Green Buildings and Cities, and the creator of the HouseZero project. “We want to demonstrate what’s possible, show how this can be replicated almost anywhere, and solve one of the world’s biggest energy problems — inefficient existing buildings.”

Ultimately, HouseZero will use near-zero energy, use no electric light during daytime, and produce zero carbon emissions, the CGBC says. HouseZero’s HVAC system will be replaced with thermal mass, and a ground source heat pump for extreme cold. A solar vent will instigate buoyancy-driven ventilation and triple-glazed windows will employ natural cross ventilation through a manual and automated system that monitors for temperature, humidity, and air quality.