5 Aspects of a Green Building
The "green revolution" is underway. Many people, homeowners, renters, landlords, builders, bankers, and insurance brokers alike have heard questions and made judgments based on "green thinking" customers. However, there seems to be a lack of information passed on from the design & construction community to the homebuyer / homebuilders marketplace. This article will focus on five essential components that make up a green building.
1. Choosing a Site
Buying or constructing a building always starts with this question. Where? Before you can entirely define what will be bought or built, the Owner needs to decide where will it go. Once the site is determined, the building can be laid out to maximize the use of its site. Before any building materials are used, before any money is spent, and before a site is wasted to developer convenience, a building Owner needs to make best use of the site on which the building will be placed. Seems like common sense, correct? The best "bang for your buck" in building or buying a green building is choosing a site and building orientation that aptly makes use of its natural settings and, of course, the sun. A building's orientation to the sun can have a major impact on overall energy consumption, occupant comfort, glare issues, and natural light. When laying out your building on undeveloped land, the goal should be to maximize your southern exposure (in our climate zone). This means orienting a building the long way on its east-west axis. Focus your glazing efforts on the south face as it will increase the amount of "free heat" harvested in the winter months. Including massive interior materials such as a bare concrete floor, ceramic tile, or a masonry hearth in this area of the home will absorb heat during the day and radiate that heat at night when temperatures dive. In the summer months, these south-facing windows will need to be shaded by either a roof overhang, trellis, or sunshades. If the design of your roof already included eaves, a simple calculation is needed to determine the length of overhang needed to optimize passive solar gain. This strategy costs a homeowner no additional money, yet can save thousands of dollars in energy over a few years.
2. Minimizing Waste
Many industries use the term "lean" in their operations. Simply put, it means doing more with less, and conceptualizes that anything left unused is a waste of money. Those ideals are embedded within green building. Doing more with less, not wasting materials, and optimizing the layout of your space through simple, smart design can have a major impact on the environment and the economics of building a new home. This strategy, again, costs no additional money. In fact, if done correctly, should save the Owner money on the cost of construction. The costs of construction are passed through to the homeowner as a building is
3. Energy Efficiency
Conserving energy is at the core of a green building's design. To create an efficient structure you must think of the house as a whole system. All the systems are intertwined: the furnace, the air conditioner, the appliances, the lighting, the building insulation, the water heater, and even the occupant's behavior. All these pieces contribute to a building's overall energy budget. Once you have taken advantage of passive solar harvesting (if you are able due to site constrictions), the next place to start is the building envelope (i.e. the floors, walls, roof, and associated insulation). Properly air sealing and insulating a home has the most economic benefit per dollar spent on construction... up to a point. Obviously, there is a point a diminishing returns on continuing to insulate. For a green home, I would recommend at least an R-50 roof and R-21 walls while implementing advanced air sealing techniques. Alternative envelope materials such as insulated concrete forms (ICFs) or structural insulated panels (SIPs) make for a very consistent and tight envelope while minimizing the risk of energy loss due to poor installation. After the envelope, attack the efficiency ratings of your home air heating and cooling systems. Installing a 98% efficient furnace with a 16 SEER rated air conditioning unit may cost more money up front, but will usually pay themselves off within a 5 year window. If you do not plan to stay in the house for 5 years, consider the investment a "green mutual fund" off of which you are earning 14% on your money. Next, make sure your home appliances, especially your refrigerator and water heater, are Energy Star(r) rated. Most appliances are capable of earning Energy Star's stamp of approval and are at equal or negligibly different cost. On lighting... never mind, this one is too obvious to explain. DO NOT USE INCANDESCENT BULBS, ANYWHERE, PERIOD. Compact fluorescent and LED technologies are equal to or better than any light an incandescent bulb can put out. Another downside to incandescents is that they only convert about 10% of the energy they use into light; the other 90% is put off as heat. In the summer time, it does not make any sense to run your air conditioner while simultaneously run 15 to 20 "mini heaters" in the form of incandescent light bulbs.
Finally, do good by what your parents taught you. Turn off the lights when not in a room. Use a programmable thermostat. Do not open the fridge door only to stare and hope the food changes into something more appealing to eat. Isn't it amazing that as we grow wiser, we realize that our parents were right along? But don't tell them I said that.
It would be a mistake not to mention water efficiency in this category. As we all know but have not yet felt because of our geographical location, water is becoming a scarce resource on our planet. A green building does not ignore the relative cheapness of water. Low-flow fixtures such as faucets, showerheads, and toilets not only conserve water, but also conserve energy (hot water). In addition did you know we pay our sewer bill based on how much water we consume? Watering our vast, lush, green lawn is the utter hatred of green building enthusiasts. The concept of feeding grass delicious, treated, drinkable water in the face of a planet where potable water is unattainable by so many seems to cause moral conflict. As an alternative, consider reducing the amount of green lawn you have. Instead plant native grasses, plants, or create a rain garden. Besides the water you are buying, you also pay a sanitary waste charge for each unit of water sprinkled on the earth.
4. Materials Selection
Buildings are an amazing compilation of materials that form the structure, feel, look, and reflect the personality of the homeowner. Consider these materials that make up a majority of our homes: wood, metals such as steel, concrete (water, aggregate, cement), masonry, oil-based products such as asphalt and vinyl, glass and gypsum. Each of these materials can serve a different purpose for a building, but which is the more-sustainable choice? Like every question ever asked, the answer is "it depends." On one hand, wood is a renewable resource. As it is cut down, a new tree can be planted in its place to grow and make more wood. On the other hand, concrete can be made from local components and can last for 100 years or more. Steel is 100% recyclable, while vinyl products are not (at least in our area). The material selection game could run a person in circles, especially when they consider the embodied energy that went into harvesting, manufacturing, and transporting a material to its final resting place. For example, wood comes from the lumberyard, which came from the distributor, which came from the secondary mill, which came from the sawmill, which came from the forester. Huh? Did it even come from Minnesota, a state rich in wood resources? Maybe. But, let's say you went the extra step to purchase lumber certified by the Forest Stewardship Council (FSC), thereby ensuring the wood was sustainably harvested and processed. This "green wood" surely came from a local source right? Most likely not. In comparison, concrete is an incredibly durable and flexible building material. Cement, a key component to any concrete mix, is extremely energy intense to mine and process. By comparison concrete is a much more energy intensive building material than wood, but if it lasts twice as long might we be better off? Only if its embodied energy is less than twice that of the wood. Strikingly, most people only focus their green efforts on finishes such as paint, flooring, and countertops. Choosing bamboo flooring, strawboard cabinets, recycled glass countertops, and finishes with low volatile organic compounds (VOCs) might make a homeowner feel green and fuzzy, but what they fail to understand is that these material impacts are just a tiny fraction of the embodied energy within the home's materials. Not getting bogged down by the details is important in materials selection. Generally speaking, recycled or recyclable materials are a better choice than virgin materials. Local materials are better than non-local. And do a little investigation into the manufacture/processing of the materials you are purchasing. If you have seen how it is made and you still feel good buying it, you have probably made a good decision.
5. Indoor Air Quality
A green building is a healthy building. We spend the majority of our lives inside buildings, whether it be at home or at work. We deserve fresh air, free from pollutants and toxins. To accomplish these goals we once again have to consider the whole house as a system. Each component of the system has the ability to affect the quality of the air we breathe within a building. The building's HVAC systems can be designed to introduce fresh air into your building at a specified rate. With a tight, well-sealed building envelope, an air exchanger with heat recovery (often referred to as a heat recovery ventilator - HRV) can introduce fresh air to your building while recovering energy from the exhaust. Every well-sealed building needs one of these or you will have very poor indoor air quality. The interior finishes of the walls, floors, ceilings, furniture, and coatings also play a significant role in the quality of your air. Selecting products with low or no VOCs is a low or no cost decision that should not be a decision at all. Choosing particleboard and furniture assembled without the use of urea-formaldehyde is also a no-brainer. Generally, any material that gives off a "new building smell" or "new car smell" is not good for your health. Return it.
These 5 aspects can be related across any building: commercial, residential, existing, or new construction. The only difficulty with an existing structure is site selection and building orientation (although that can be modified with enough economic fortitude). Green buildings and homes are not a passing fad. However, I would expect the term "green" to eventually be replaced by "better," "smarter," or "healthier." Why would you not want to build a better, smarter, or healthier building? The economics of many of the aforementioned strategies work, it just takes a little bit of patience.
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