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.
video

Wednesday, December 1, 2010

You Don't Have to Paint Your Pebbles to Be Green


I spent several years of my youth in Tucson, AZ. Tucson averages about 10 inches of rain a year (compare that to 40 for Charlotte), and it is not uncommon to go weeks without rain, especially in the hottest summer months.

Plants adapt to this environment by having large root systems and few leaves, or in the case of cacti they store water in their fleshy pads. Animals adapt by basically staying out of the heat. The desert is alive with animals at night and in the early morning, but come high noon all of the critters have gone underground, literally.

Humans have adapted to this dry, hot climate by getting their rocks colored. Yes, you read that right. They color their rocks.

Now, many people who move to the desert try to bring their hometown with them. They plant lots of grass, irrigate it endlessly, and plant non-native trees that remind them of their home back East. This is why people who move to the desert to escape the allergies find their allergies worse than ever before.

But, there's another group of people who don't try to beat the heat, but rather join it. They plant native species like cacti and mesquite trees, and instead of grass their front yards are landscaped with pebbles. But, to trick you into thinking they have a verdant grass yard, every spring they get the pebbles painted green. It's really hard to tell the difference between a painted pebble and grass until you get within a half-mile.

In North Carolina we don't have the harsh conditions of the desert. Nonetheless, water is a precious resource, and one that must be conserved and managed just like we do with electricity. Not too many years ago we experienced the driest year in recorded history, with water restrictions, brown lawns, and dirty cars. We continue to create more people, but the water supply is relatively fixed. That is not a sustainable equation.

We use some simple yet effective approaches to conserving water on our LEED homes. Landscaping is comprised entirely of native plants that by definition don't require supplemental irrigation. Turf is limited to no more than 40% of the softscape, and we use a drought tolerant turf. To the extent we use irrigation systems, they are designed to be efficient and to only come on when needed (and not to come on in the middle of a downpour). Lots are tilled prior to planting so that rain will soak into the soil instead of running off of compacted clay.

Inside, we use low flow faucets, toilets and shower heads which conserve water but provide the same level of performance as standard fixtures. The design of the plumbing system is important too, with points earned if all of the fixtures are located within a certain distance of the hot water source.

There are more exotic things that can be done to save water, like diverting "gray" water from showers and sinks to be used to flush toilets, or collecting rainwater in a cistern to be used for irrigation. These approaches are not for everyone's budget or taste.

Our approach helps conserve water, which is one of our most precious resources. In turn the homeowner saves on their water bills. Equally important, a LEED home is also a nicely landscaped home. Check back in a month or so and I'll post some photos of the landscaping on the home we're presently building on James Alexander Way in downtown Davidson. I think you'll be impressed.