The Annual Spring Parade of Homes is on the last week in the Wichita Metro Area. There are some great homes out there. Lots of amenities to consider. Everyone has their own lifestyle and looks for a floor plan to fit. They all have their sense of taste and can look at the colors, finishes and visual effects.
Every builder says they build an energy efficient home. Energy Efficiency is built in behind the walls. It is usually not seen. Energy Efficiency is about people and how they install the items that create the efficiency. The specific items are less important then the way they are installed. Generally, the manufacturers install instructions must be followed.
Wichita – Sedgwick County has not adopted any code provisions for energy efficiency in new homes. It may be legal to build a home with no insulation, but is that a wise decision? No one thinks so. So how much is enough and is it installed correctly? In this area we are reliant on the free enterprise approach energy efficiency in new homes.
Phoenix, AZ has an energy code, yet the free enterprise market based system has upped the game for buyers. Here is a recent article in the Phoenix Newspaper about how a home buyer can see what is behind the walls.
The practice of covering sheathing with asphalt impregnated papers has given way to the use of synthetic fabrics, known as house wrap; or spray on coatings. There are factory applied coatings on some brands of sheathing and some types of coatings are field applied. Along with the discussions of fiberglass / cellulose in the insulating of homes, there has been plenty of discussion about the merits of one form or another of WRBs.
As with any step in the building process, I believe it is less about the product and more about the people. Products that are hard to install will be less successful then others. Installers that are not properly trained; work that is not verified in some manner can defeat the proper performance of the best products.
What does the WRB do for a home. First it provides a drainage plane behind the siding to divert rain and other weather related moisture from wetting the sheathing. Second, when all manufacturers install instructions are followed it can act as an air barrier, reducing infiltration. For the house wrap type fabrics, this means properly lapped, using capped fasteners, and then taped. Finding house wrap installed according to manufacturer’s install directions is rare.
When all three of these directions are not followed, not only are the potential qualities of an air barrier not present, the potential for water to run behind an uncapped fastener, or an incorrectly lapped joint, which is also untaped. Repeated wetting of the sheathing over time, will eventually result in rot and the accompanying problems.
A local Wichita Home Builder, G.J. Gardner has just finished two homes based on the same floor plan. These homes went through the independent verification process involved in obtaining a HERS Rating. These homes utilized the same sub-contractors and types of insulation. The only difference in construction was the use of a job site applied spray on WRB, in place of a house wrap type fabric.
One part of this verification process is a Blower Door Test. This test simulates the effects of a 20 mph wind on all sides of the home at the same time. Blower Door testing has been completed on homes since the late 1970’s. Energy efficiency programs and building codes have consistently recognized the value of a Blower Door test on each home.
The value of doing a Blower Door test on each home is primarily to check the work of all subs has not compromised the Builder’s plan for an energy efficient home. Many existing homes, have a test rate of 7 – 12 or higher rates of air exchange during the test. The 2012 code requirement is 3 on this scale, and lower is better.
The use of 4×8 sheet goods for sheathing and other simple, and inexpensive techniques have brought the infiltration rates down. This reduces the cases of cold drafty homes, and significantly lowering the energy use of a home.
The Blower Door test can verify the quality of work involved with installing the WRB, specifically the degree of sealing of the outside of the sheathing. In the case of the two homes involved in this comparison, there was a change of 20% in the measured infiltration rates of the two homes.
In completing the Blower Door tests, we used the ANSI / RESNET published standard of a Multi-point test. These results were entered into a software package provided by the maker of the blower door, The Energy Conservatory, Below is a comparison screen between the two Blower Door Tests.
I would like to thank Wade Wilkinson, with GJ Gardner of Wichita; his subcontractors and their technicians for building quality energy efficient homes. I enjoy being able to verify the quality of their work.
If you would like to see this home, it is currently in the Fall 2014, WABA Parade of Homes. It is located in the Country Hollow Development. Between Kellogg and Harry on 127th and East to Glen Hills Court, on the corner. Find out also about the HERS Index earned by this home. It will save you operating costs on your Energy Bills.
I receive an email news letter each Friday as a member of Wichita Area Builders Association and NAHB, the local and national Builders Trade Groups. This is titled Monday Morning Briefing. There are usually 8 to 10 concise articles of interest to the residential building industry. NAHB has an outstanding Research Arm. Every time they post something they have researched, I learn something.
Some of these posts are self-promotional. I don’t blame them. They work hard and deserve to put that hard work out for everyone to know about.
In this case, the article that caught my attention relates to work the NAHB has done with other industry trade groups to advance the shared knowledge for builders, buyers, real estate agents, appraisers and others. Everyone in the home sales transaction benefits from common, verified sources of information about specific homes.
Everyone seems to have something good to accomplish on Earth Day this year. Twitter and Facebook have had regular comments all day. Energy Star had a Tweet Up going online with people from all over the country. GE donated some LED lamps for a give away. So to get in the spirit, here is what I accomplished.
Wichita Habitat for Humanity builds Energy Star new homes. One of the requirements is to limit duct leakage, by strictly following Wichita City Code and all manufacturers instructions for materials. The professional standard established by the Air Conditioning Contractors nationwide is 6% of system air flow. Energy Star requires 6 cfm (or less) of leakage with a duct pressure test for each 100 square feet of floor area. This home tested at 50% of the Energy Star Requirement. The system tested at 5% of system airflow. Great work! The mechanical contractor on this house is Cook’s HVAC of Wichita.
This afternoon, I did a Blower Door Test. This test measures the energy loss due to infiltration. This again, was new construction and the first HERS Rated Home in Wichita for the season. Wichita / Sedgwick County have not adopted the Energy code. If they were enforcing the 2009 version, this home would have exceeded the requirement by almost 50%. It is 20% above the requirement for an Energy Star New home. Great Work! This shout out goes to a number of contractors.
Air Sealing has many pieces. Framers, electricians, plumbers can all cause many problems for this test. So when they cooperate to help achieve the end result, it is a good thing. Fibrous insulation (Rockwood, Fiberglas, Cellulose), by itself does not effect infiltration. Air will move through all of them. The insulators must install the insulation correctly. They must caulk many places. I observed much of this during my pre-drywall inspection.
I am sure Wade will pipe in here for a comment and a shout out for these subcontractors. Wade Wilkinson is principal of GJ Gardner Homes of Wichita. This home will be their entry in the Wichita Area Builders Association’s Spring Parade of Homes. You can read my Post on the WABA Parade of Homes
Verifying good workmanship by builders and contractors is a great part of being a HERS Rater. What did you do for Earth Day?
It is Spring! You can always tell, because the Pears and Redbuds are blooming and just around the corner is the Wichita Area Builders Assoc. Spring Parade of Homes. This annual event is always fun in the spring to get out and see what is happening in the world of new homes.