This Earth Week we all felt a little conscious about our footprint on this planet; With that said, we all know of many ways to contribute to this cause, we can recycle, use refillable water bottles, we could even buy an electric car. Now, there is one major area where we could make a life-long impact. That’s where we will spend 80% of our lives, our home.
In order to understand how we can make a difference in our environment, we have to know what people are talking about when it comes green homes.
Here is a list of the most common terms used in the green construction industry:
To kick things off, we are going define R-values. We all heard about it, it’s the unit of measure of a material’s resistance to conductive heat flow. Think about it this way, that exterior wall in your home is made of several layers with the foremost purpose of slowing down heat transfer. Heat moves in and out of your house, walls prevent it. The higher the R-Value, the higher the insulation properties of the shell.
According to a study by the NAHB (National Association of Home Builders) most of the homes built in the 1970s, in our region, have an R-Value of 11.
Today, some green builders in our area are achieving R-Values in the upper 30s.
Check out: http://www.jepsystem.com/technical-reports/
Since we are talking about insulation, Thermal Bridging plays a key role in the overall value of your insulation. Thermal Bridging is a phenomenon that occurs when one of the material that make up the wall, conducts heat at a faster rate than the others. The most common thermal bridges are your wall studs.
Effects of Thermal Bridging:
Higher energy bills. You have a leak, and this is making your heating rig work harder.
Mold formation. Thermal Bridging can cause condensation in the transfer area. Consequently, the moisture can lead to mold growth.
Occupant discomfort. You might have cold or hot areas in the home that you just don’t know why. Well here is the answer, You are welcome! Note that, not all thermal bridges cause these severe effects. However, it will for sure affect all your shades of green.
The Home Energy Rating System, that pretty much settles it. “is the industry standard by which a home's energy efficiency is measured. It’s also the nationally recognized system for inspecting and calculating a home's energy performance” https://www.resnet.us/hers-index
A typical new home has a HERS rating of 100, an existing older home is usually over 130. Net Zero homes, or HERS rating of 0 is a high performance home where the renewable energy system is sustaining all of its annual energy consumption.
Passive Solar Design.
Is a home built to take advantage of the site, climate and building materials to reduce energy use. A successful passive solar design, takes advantage of the sun exposure to heat spaces in the winter and decreases the direct sun-light during the summer. A passive solar design does not require solar panels to absorb the sun’s energy.
Flagstaff is a great place to implement passive solar. However, passive solar requires south-facing windows and a lot of Flagstaff residents opt for the north-facing mountain views.
In this category we can find two options, Solar Voltaic and Solar Thermal. A solar photo-voltaic (PV) module is an array of cells that convert light (photons) into electricity (voltage) if you want to be completely of the grid, this is the system for you. Although, many argue the upfront cost of a PV system, the price tag on these babies have dropped more than 30% over the last 10 years, and if you combine it with a good Building Envelope (we will talk about that), it will pay for itself in just about 10 years.
The solar thermal system, collects solar radiation to heat air and/or water. The most typical systems use panels to heat water. Think of a water hose and how hot the water gets during sun exposure. It is the same principle in a Solar Thermal design. Water can be heated to boiling temperatures and used as a hot water supply for space heating when used for in-floor radiant systems, and for general hot water use. For more information, contact your local Solar Thermal professional, Tom Scheel with Radiance Heating and Plumbing at: http://www.radianceheating.com/Contact.html
Flagstaff is the perfect area for Solar-Thermal!
Is the shell that separates the livable space of a building with the outdoor exposed world. This shell is made up of different components such as, external walls, windows, roof, and the floor of a building. A tighter envelope keeps conditioned air indoors, consequently reducing the load on the HVAC system. A building envelope plays a major role on the efficiency of your home. An excellent building envelope will allow you to use more affordable solar systems, and directly affect upfront cost and length of pay-off.
The goal of sustainable design is to reduce the impact our lives cost the planet. We must change course and avoid the depletion of our resources. A typical stick frame home takes approximately 85 trees, that’s why the first step to minimize impact is to understand the roots of the issue and considering every step to build a home. A sustainable design is a secure, healthy, productive, and accessible home built to cause minor impact in its immediate environment and will continue to do so throughout its life cycle.
Stay tuned for more green construction lingoes next week; we will talk about: Continuous insulation, conditioned attic space, grey water systems, and more.