Thursday, December 30, 2010
Tighten It Up!
As we're wrapping up construction of 631 James Alexander Way, a number of tests for both ENERGY STAR and LEED certification are conducted. These tests help to verify that the house performs as designed, with the result being not only a more efficient home, but also a comfortable and healthy home as well.
This video shows a blower door test being conducted. The blower door simulates the effects of a 35 mile per hour wind on the home, and measures how much air leaks out of the house under this condition.
For a house this size, the maximum air leakage that is permissible under ENERGY STAR guidelines is about 2,200 CFM (cubic feet per minute). As the video shows, the actual leakage from this house was subsequently less. Although the video shows a rate of about 900 cfm, the official test result was just over 700 cfm (we later discovered that someone had cracked open a window during the video 'shoot'). Thus, the house is about three times as tight as ENERGY STAR requires, and as the technician states, about six times tighter than a "to code," non-ENERGY STAR home.
What does this mean to the homeowner? First, a tight home results in significantly greater energy efficiency and lower utility bills. Those who followed the construction and testing of our LEED certified home at 233 Catawba Avenue in Davidson will recall that utility bills are half of those of similar sized homes. Second, a more comfortable home. Some of the other tests that are conducted verify that the output from the HVAC system is properly distributed, and temperatures and pressures are balanced throughout the house. Thus, the chances of cold or hot spots in the home are greatly reduced.
LEED is your customer's assurance that a home has not only been designed to the highest standards, but also tested to verify compliance with those standards. Do not settle for less.