Cascade Built Blog
February 4, 2008
LEED Silver Townhouses
Posted by admin, 9:41 PM
Huge Ass City blogs about the Jackson Townhouses:
“Seattle’s first LEED certified townhouses, designed by OPA, built by Cascade Built. Located in the Central Area, at 712 26th S (one block west of MLK Way, two blocks south of Jackson), currently priced at $450k.
They claim these townhouses will be 30-50% more energy efficient than a typical home. That’s pretty impressive given that they haven’t done anything that radical. The most unusual feature: heat recovery ventilation….” Read More Here
They liked the concept, but wondered how we hit 30-50% energy efficiency without radical strategies, except the Heat Recovery Vent. They’re absolutely right – we employed few radical strategies, unless you consider the cumulative effect of several known simple strategies as radical, which it is in most spec homes. Here are some of the energy efficiency tools we employed to achieve impressive net gains:
- Advanced Framing (24″ on center wall studs, 2-stud corners, drywall clips) means less wood and more insulation in the exterior walls (25-30% less wood & more insulation)
- Blown-in insulation – instead of cheap “batts” we used dense pack blown-in insulation to improve R-value
- Air Sealing – One of the advantages of LEED certification is they measure the air tightness of the building and won’t certify until you hit a certain level. We didn’t measure up on the first test, so we went back and improved until we could meet the standard (turns out one of the subcontractors had made a mistake that resulted in some building envelope air leakage).
- Energy Efficient Windows – Code requires U-factor of .40, we were less than .32 average, a significant contribution to overall efficiency.
- Heat Recovery Vent – ventilate without losing heat, about 65% efficient, so on a 30F day you’re bringing in 55F degree outside air. Most houses use window trickle vents, which let in 30 F air on a 30 F day.
- Tankless hot water – don’t pay for “standby loss” with a hot water tank. Just heat the water you are using. Up to 50% water heating cost savings.
- Daylighting – natural light floods this home, so you won’t need the lights, except after dark
- Energy Star Advanced Lighting Package – use of mostly fluorescent lighting reduces lighting costs by up to 75%
- Radiant heat – efficiency claims for radiant heat are more abundant than the evidence to support those claims, but there it’s probably somewhat more efficient.
