Energy Efficiency: It’s Not Only about Your Wallet
Monday, June 3rd, 2013 | Uncategorized | No Comments
Planning and building an energy efficient home not only reduces your immediate cost for heating and cooling, but it also continues to provide savings for the life of the home, which, in many cases, is well beyond our own use of the home. Should you ever decide to sell, a home built for energy efficient savings is always an attractive feature. It also reduces the carbon footprint for the home, which helps our environment and reduces dependence on foreign oil. A well-planned home uses less energy to heat and cool and is more comfortable because the home is very evenly heated and cooled with no hot or cold areas. A home that is properly insulated can use smaller and less complicated HVAC equipment because heating and cooling loads are reduced. This will not only reduce the cost of equipment, but can lower utility bills by as much as 40%-50% for the life of the home.
The most important thing to consider when planning a new home is the location and orientation of the home on your property. By looking at the location, we know if heating or cooling will be the major concern. Because of our mild winters here in East Tennessee, cooling is more important.
Although we don’t always have the opportunity to orient the home on the lot to take full advantage of the sun, there are still many things you can do to make the home more comfortable and energy efficient. The design should consider things like the placement of the garage to block northern winds, use of less windows on the north side of the home, and more windows on the south side to take advantage of the sun in the winter months. The type of windows (Heat Mirror) used on the south and fest facing sides of the home can block damaging UV rays from heating up the living spaces and prevent sun damage to furniture and finishes in the summer. Planting deciduous trees and bushes can also help reduce energy cost by shading parts of the home in the summer months, but take full advantage of the warmth of the sun in the winter months.
The second thing to consider, but just as important, is properly insulating the home. Insulation is something that is not easily added to the foundation and walls of a home once it is built and is too often easily overlooked because it doesn’t appear to add value like granite countertops or beautiful flooring does to a home. It disappears behind the walls of the home and is never seen again except in the reflection of your comfort and utility bills. However, proper insulation in a home, especially considering energy efficient savings, is of upmost importance.
There are several ways to insulate the home including Fiberglass Batts, Spray-in-Place Foam, Insulated Structural Panels (SIPs), Insulated Concrete Forms (ICFs), Blown-in-Place Cellulose, and combinations of foam board and fiberglass insulation.
First, let’s discuss how a home is typically constructed. Walls are framed using either 2×4 or 2×6 studs, and then fiberglass insulation is added. The attic space is then insulated with either Batts, Blown-in insulation, or a combination of both. When we consider that 25% of the wall and ceiling is framing material and therefore not insulated (wood has a very low R value of about 1-R per inch) that means that whatever the “R” value of the insulation we use is reduced by 25%. Furthermore, let’s consider that all insulation is tested at 75 degrees so that special chambers are not needed to achieve test results. If we lower the temperature to below zero, an R-19 Batt actually performs at an R-9.2. This was proven in a study conducted by Oak Ridge National Laboratories using several homes insulated by different products that were monitored and tested during the course of a year. In contrast, when using foam insulation in a test home, the R values increased as the temperature dropped.
The new 2012 IRC (International Residential Code) requires R-49 in the ceiling and R-20 in the walls, which can only be achieved by adding a layer of foam insulation to the walls of a conventionally framed home. Because of this, the requirement was reduced by local building code officials to R-38 in ceilings and R-13 in walls to help keep cost down by not adding another layer of insulation to the wall component. Now, let’s consider standard R-13 in the walls and reduce the R value by the 48% proven by the study conducted by ONL, and you have an effective R value of R 6.7. Not too good, is it?
Fiberglass is a poor choice for insulation, but builders continue to use it because it is easy to install and much less costly (initially) to insulate a home. Insulated Structural Panels (SIPs), Insulated Concrete Forms (ICFs), and Spray-in-Place Foam is more costly to install, but pays big dividends in comfort and energy savings during the useful life of a building, which is more than 100 years.
Our company has been using Structural Insulated Panels for walls and vaulted ceilings since 1989. Because of their strength and insulation value, they have been proven to be superior to standard “stick” construction. They also have proven to our clients, through much lower utility bills and overall comfort in their homes, to justify the initial higher cost of construction.
Ultimately, it is up to each of us to decide the impact and cost that using current building science to improve the energy efficiency of our homes will have in our lives now and in the future.
Next month we will discuss working with banks, title companies, and builders.
Jamison Custom Homes
(423) 884-3886
www.jamisonhomestn.com
