Planning ahead, using the same design team, and comprehensive whole house performance evaluation all keys to this unique 10-year LEED for Homes project

Don’t all major home renovations span decades?

Jim Newman and Sarah Slaughter bought a rather pedestrian Cambridge home in 1996 and began full renovation in 2001, recently completing the metamorphosis in 2010. They have always taken the long view on both the environment and their own home’s performance. As building professionals in their own right, Jim and Sarah worked closely with NPS Studios and their contractor on the energy and resource efficiency aspects during BOTH phases of their whole-house renovation.

Can the Newman-Slaughter two-phase gut rehab LEED for Homes qualify?

“It’s a special project that will qualify,” says Mark Price, Senior Sustainability Specialist with Steve Winter Associates, a LEED for Homes AP and rater. Mark feels pretty strongly that there are five aspects of this project that justify treating this two-phase project as a single one:

1. Existing comprehensive documentation – “Jim and the design/construction team took detailed and numerous photos of open-cavity walls and roofs, had a full set of plans, and specifications for Phase I,” says Mark. “If I can verify everything from Phase I, I can count it.”

“I think we spent three straight hours pouring over the photos and nailing down just exactly where the building envelope (thermal barrier and air barrier) was, how Phase I and II elements lined up,” says Jim.

2. Same design firm – “We always had a two-phase plan with NPS Studios,” says Jim. “We just did not know exactly how closely (or not) Phase II might follow Phase I. And since LEED for Homes did not exist during Phase I, it was a really interesting opportunity to see if what we had accomplished in Phase I could dovetail with Phase II to make the whole project eligible for LEED for Homes.”

3. Extensive performance testing of Phase I – Working with just an infrared camera to start, and then adding steady depressurization of the home with a blower door to exaggerate thermal and air barrier short circuits, Mark and Jim carefully identified places in Phase I that would need to be addressed as part of Phase II. “There were not a lot of them, but they were significant,” explains Mark. “But Sarah and Jim made the commitment to pull the entire home’s performance up to the LEED for Homes standards.”

4. Conservative assessment – Jim agreed with Mark’s decision to essentially give all of the Phase I details, such as quality of insulation, a conservative rating (grade II – a less than perfect installation).

5. Phase I changes as part of Phase II – Sarah and Jim went through the LEED for Homes rating system line by line with Mark Price. For example, when they got to the existing masonry fireplace, Mark was unsure about how they would feel about adding operable doors, a LEED for Homes prerequisite. Jim relates,” Actually, we had wanted to add airtight doors since we put the fireplace in and all we needed was this push.”

Not all of the resolutions required were quite that easy. When the performance testing indicated that air sealing and insulating on Phase I living room eaves would mean taking down the soffit and spray foaming that whole area, that is no small project. “It’s not easy to pile on that sort of effort and expense,” remarks Jim. “But the question is: is it worth it? And we decided the answer was yes because it made our home more energy efficient, comfortable and durable.”

Mechanical serendipity

During Phase I, NPS defined a zone heating and cooling system, and the HVAC contractor decided to install two 3.5-ton AC units. One services the downstairs with ducts and air handler in the unconditioned basement, and one services the upstairs from the unconditioned attic. Seven tons of cooling for less than 3,000 square feet in a cold climate! Problem or opportunity?

“Good question!” quips Jim. LEED for Homes requirements would mean eliminating the ducts and air handler in the unconditioned basement. Could the upstairs unit (now inside the insulated unvented cathedralized Phase I attic) provide sufficient comfort throughout the whole house, directly conditioning the upstairs and indirectly the downstairs? “After the Phase II improvements, the whole house loads can now be served by a single unit,” adds Mark.

“We have now had some real-world testing of just the upstairs delivery and it does fine for the open areas (living room, dining room, and kitchen) but more tweaking is probably needed to provide sufficient comfort in the two separate downstairs rooms (library and bedroom),” says Jim. “The redistribution accomplished by the whole house ventilation system is key to this. Probably just use the second 3.5 ton compressor as an in-place spare,” Jim says with a smile.

Using LEED for Homes: point chasing or informing the process?

For Jim Newman and Sarah Slaughter, there is just one way to use any rating system. “It informs, not drives the process,” states Jim. “We developed a package of water, energy, and resource efficiency features for our home renovation and used the LEED for Homes prerequisites and credits as just a double check. The points and rating are what they are.”

But if you look at the extensive features in the project detail sidebar, Sarah and Jim ended up with a high performance home; it just took a while to get there.