Archives

Solar Panels
What is Green Building?

What is Green Building?

greenbuilding2

I’ve been wanting to write an article for a while that is a general overview of various green building terms, energy systems, and strategies. I’ve found that as green building is becoming more popular, green jargon is seldom defined clearly for the layperson and rarely all in one place. We often assume that we know what something means, but its helpful to explore the true definition. So, here is a rather lengthy article that I’ve written that aims to demystify the popular terminology used within the green building industry. This will be published as 6 smaller articles in the EcoZone section of “The Bozone” (a local publication). -Emily Varmecky, Co-Owner of Greenovision Home Design

Green building is a rapidly growing segment of the U.S. construction industry. It is estimated that green building represented 40-48% of new non-residential construction in 2015. It is also reported that in 2015, “62% of firms building new single-family homes report that they are doing more than 15% of their projects green.” It seems that although discussions of green building are becoming more popular, green jargon is rarely defined for the layperson. My goal for this article is to demystify the popular terminology used within the green building industry. I will choose common building terms, energy systems, and strategies then define and generalize them to make them more understandable.

What is Green Building? Green building refers to both the structure and the process of construction “that are environmentally responsible and resource-efficient throughout a building’s life-cycle: from siting to design, construction, operation, maintenance, renovation, and demolition.” The goal of green building is “to reduce the overall impact of the built environment on human health and the natural environment.” There are a variety of methods that may be applied to reduce this impact which may include using water, energy, construction materials, and other resources efficiently and “reducing waste, pollution, and environmental degradation.”

For many professionals within the housing and construction industry, green building is a broad term describing the design or construction of a structure that is environmentally responsible in some manner. Building professionals can interpret environmental responsibility in a variety of different ways ranging from applying a complex method of energy-efficient design strategies into their structures to simply recycling cardboard within their business. Green washing is common in all areas of business and consumerism, including the housing industry. Green washing is a form of propaganda in which “green marketing is used to promote the perception that an organization’s products, aims, or policies are environmentally friendly.” Just because a company claims to be green, they may be interpreting green in their own manner, may be applying certain green principles on a spectrum, or may not be green at all. As I continue to explore various green building principles in this article, it is important to understand that these definitions are the ideals (principles to be aimed at), but should be critically examined when construction professionals are applying them in the field or are using the terms within their business.

Sustainable Building: The word sustainable means “able to be used without being completely used up or destroyed” and “able to last or continue for a long time.” In the construction industry, it is difficult to find a definition of sustainable building that is not synonymous with green building, but in my opinion, this term is slightly different. To me, sustainable building encompasses the utilization of renewable resources, which are “resources that can be replaced naturally and can be used again.” Sustainable energy systems within a home use energy efficiently in a manner that doesn’t use up all of the energy available and allows the home to consume energy for a long time. Fossil fuel is considered by many scientists to be a finite resource, therefore although using fossil fuels efficiently within a home or building is considered green, this usage is not necessarily sustainable. In many parts of the world, however, the sun shines consistently, providing an energy source that never runs out. Solar energy systems are therefore considered sustainable.

Sustainable construction materials can be materials that are grown and produced in methods that allow those materials to be continually produced, the usage of materials that last a long time, or the usage of materials that are reused or recycled. Fast growth pine, for example, is a building material that is grown and milled here in Montana. When responsibly harvested, a pine forest can regenerate and provide lumber for future generations without significant harm to the environment. Using locally available materials also minimizes long distance shipping, another environmentally-friendly practice.

The usage of metal construction material may be considered to be sustainable because of its durability. Although ore is a finite resource like fossil fuel, metal is long lasting and can be recycled into new materials. Metal roofing on a building can last significantly longer than asphalt shingles, which generally last 15-20 years. When asphalt shingles are spent, there are few ways to recycle or reuse them, so they usually end up as trash. However, when a metal roof is finally worn out, the metal can be recycled.

Energy-Efficient: Energy-efficient is a broad term used to describe a building or system within a building that produces and/or uses energy in a less wasteful manner. It can also be described as “using less energy to provide the same service.” A variety of strategies can be used to promote energy-efficiency that may include design methods, construction methods, materials, and technologies. Some methods may be active such as radiant floor heating or an “Energy Star” dishwasher and some strategies may be passive such as passive solar heating or well-insulated windows.

Before I explore various energy-efficient and sustainable energy systems, it is important to understand how we use energy within residential homes and other structures. In Montana, the three demands for energy within a home are: heating of your home spaces (accounting for about 49% of home energy usage), electricity for lighting, appliances, and air conditioning (36% of home energy usage), and lastly hot water for bathing, doing dishes, and laundry (16% of home energy usage). Passive solar, solar power, and passive cooling are generally considered renewable, sustainable energy production methods. Liquid solar, geothermal energy, and radiant floor heating are usually considered energy-efficient systems.

Passive Solar: In passive solar design, the sun’s natural energy is harnessed to help heat a home. “Windows, walls, and floors designed to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer.” This process is passive because it requires no plumbing or wiring, just good design. There are different passive solar strategies, but typically, sunlight enters through the building’s south facing windows and is stored as heat within a concrete floor. The heat then emanates from the floor mass during the day and night. Passive solar heating also provides natural day lighting, which reduces the need for electric lights.

Solar Power: Solar power is the conversion of sunlight into electricity, using photovoltaics (PV) or concentrated solar power (CSP). Solar electricity can be produced at the structure location (on-site) with photovoltaic arrays or can be supplied through the grid (electricity produced off-site that is delivered to the building through power lines). Although grid-tied electricity is typically produced from fossil fuels, a small amount of commercially produced electricity is derived from the sun.  “Solar energy provides four-tenths of one percent of the total energy consumed in the United States.”

Solar Water Heating (AKA Liquid Solar): Solar water heating systems use the sun’s energy to warm domestic hot water. The water is heated with solar water heating panels, which are affixed to the outside of a structure similarly to solar electric panels. “A conventional boiler or immersion heater can then be used to make the water hotter, provide hot water when solar energy is unavailable,” or store the hot water. This hot water can then be used in the kitchen, bathroom, or laundry room or can be used in a variety of different methods to help heat the building spaces.

Geothermal Energy: Geothermal energy is heat that is generated and stored within the earth that can be used to produce electricity or more commonly, be used to help heat or cool the domestic water and spaces of a building. When geothermal energy is captured on the building site, a system of water-filled pipes (closed loop or open loop) runs horizontally or vertically into the earth. The earth’s temperature stays at a consistent temperature compared to the fluctuating air temperatures throughout the seasons. The water within the pipes is preheated by the earth then is further heated by an electric-run indoor geothermal HVAC (Heating, Ventilation, and Air Conditioning) system that “compresses the heat to a higher temperature and distributes it throughout the building.” As an example, water within a geothermal well is heated to 50 degrees F. If the outdoor air temperature is 0 degrees F, the HVAC further heats to water to create a comfortable indoor temperature. If the outdoor air temperature is 100 degrees F, the 50 degree F water can be used to help cool the home.

Passive Cooling: Passive cooling is defined as “a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or nil energy consumption.” There are a variety of strategies in which this cooling method can be achieved within a building, but it usually combines energy available from the natural environment on-site with specific architectural design and building materials.  With stack effect, for example, warm air naturally rises and escapes through carefully positioned high windows or openings within a building and cooler outdoor air enters the building through low openings. “The pressure difference between the outside air and the air inside the building caused by the difference in temperature between the outside air and the inside air… is the driving force for the stack effect.” This method, when implemented correctly, can effectively cool and/or ventilate a building on a non-windy day and can be designed to require no mechanical systems.

Radiant Floor Heating & Cooling: With radiant floor heating, heat is supplied directly to the floor of a building and “relies on radiant heat transfer- the delivery of heat directly from the hot surface to the people and objects in the room via infrared radiation.” Radiant heating “is more efficient than baseboard heating and usually more efficient than forced-air heating because it eliminates duct losses.” With hydronic radiant heating, the most energy-efficient floor heating system, warm water is circulated throughout the floor systems of the building through a series of tubing. This water can be heated with fossil fuel based energy systems such as gas or oil fired boilers or can be heated with on-site energy systems such as passive solar, solar power, liquid solar, and geothermal energy.

“Sun smart radiant heating,” for example, is the combination of radiant floor heating and passive solar heating. With this system, the sun’s heat that is passively collected and stored within the mass of a concrete floor is actively circulated throughout the home via the hydronic tubing. When the radiant flooring is also connected to a water heater, the radiant floor provides heat on non-passive solar (cloudy) days. When a radiant floor is connected to a geothermal well, the 50 degree F water from the geothermal system can be circulated throughout the floor on hot days to effectively cool the building.

A simple Google search will show that there are many strong and varying opinions held by green professionals. There are a variety of different sustainable and efficient energy systems that can be used within a building. There are also a variety of different green design methods, construction methods, and material choices. There is a plethora of different reports and thoughts on which strategy or method is most effective, affordable, energy-efficient, easy to build, sustainable, etc. It generally seems, however, that the specific green methods implemented into a building depend on geographic location, available resources, budget, and personal preference.

Next in this article, I will discuss a few different green building strategies as well as green certifications. It should be noted that (along the lines of green washing) just because a green professional is certified to implement a certain strategy, it doesn’t necessarily mean that they are more qualified than a green professional who isn’t certified. For example, even if a building is not LEED Certified, it still may have been designed and built to provide environmental benefits and may have similar features as a LEED building. After researching “Not So Big House,” I discovered that designers and builders can easily become a “Not So Big House” registered professional after paying an annual fee. Of course, there are many building professionals that practice the design and construction of quality, smaller homes, but are not registered with “Not So Big House.” With training, it is also possible to be a certified Passive House or Green Building professional (among many other green building related certifications).

High Performance Walls and Roofs: Since 49% of home energy usage in Montana is for the heating of home spaces, reducing the total amount of heat required within a home is a common energy-efficiency approach. One of the best ways to use less heat is to prevent heat created in the building from leaving the building. This is done by constructing the walls and roofs to be well-sealed and insulated. There are many different design and construction methods as well as material choices for creating “better thermal barriers and fewer air leaks,” but this is usually done by creating an envelope that has a high R-value (or insulation value). This structure can then be fitted with conventional fossil fuel-run heating systems or with sustainable, energy-efficient systems. Either way, the building is still requiring less heat than if it had less insulation.

A high performance building envelope not only prevents heat loss in the colder months, it also prevents heat gain in the hotter moths. This helps promote energy-efficiency within the building during all seasons. It is very important to incorporate a ventilation system into a building that has low air leakage to prevent moisture build-up. Just as heat cannot escape this type of building, water vapor (present in all buildings) also cannot escape. Energy-efficient ventilators that limit heat loss and gain are available.

A blower door test is one method that energy professionals use to help determine a home’s airtightness. The results of a blower door test are measured as ACH units (air exchanges per hour). As a reference, older homes, like living in a ‘barn’” have a 10-20 ACH. “Average new homes with some air sealing, but no verification and little attention to detail” have a 7-10 ACH. An ACH of 3 or lower is achievable for new homes and is recommended by most green professionals.

Passive House: A Passive House is a super-insulated and extremely tightly sealed home that achieves its energy-efficiency by keeping heat within the home, rather than letting it escape and producing new heat (and vice-versa in the hotter months). Passive House requires a blower door result of 0.6 ACH, a difficult standard to achieve. There are many different Passive House strategies; some rely more on active technologies for heat production, heat recovery, and air circulation and others incorporate passive solar heating and passive cooling design strategies.

Smaller Home: According to the 2013 U.S. Census, the average newly constructed single-family American house is 2,598 square feet, hitting a new square footage record. As of 2014, “smaller homes, of 1,400 square-feet and less, [represent] 4% of homes built” and “extremely large houses, 4,000 square feet and up… account for more than 9% of new homes.” “Houses that are a little smaller but still verging on mansion territory, those between 3,000 and 4,000 square feet, made up 21.7% of new homes in 2013.”

Not to be confused with “Tiny Houses,” smaller homes are moderately-sized homes that use less of the construction budget on square-footage and instead focus that money on quality design, quality materials, and/or energy-efficiency strategies. Smaller homes typically consume less energy and use fewer construction materials than larger homes and therefore are generally more energy-efficient and green by default. “The U.S. Energy Information Administration says homes of 2,000 to 2,500 square feet use an average 102.3 million BTUs of fuel yearly — 13% less than homes that are 1,000 square feet larger.” Terms similar to smaller house may include simplified home, down-sized home, or “Not So Big House.”

LEED Certified: LEED (Leadership in Energy and Environmental Design) certification is a rating system for the design and construction of green buildings that is managed by the U.S. Green Building Council, a private non-profit organization. The owner, designer, or contractor of a building can pay a fee to have their structure approved by the organization and achieve levels of certification ranging from “LEED Certified” to “LEED Platinum.” LEED buildings are designed and built to provide environmental and economic benefits and requirements may include the use of recycled materials, energy efficiency, renewable energy, water conservation, etc. Additionally, building professionals themselves can choose to become LEED Certified after paying a fee and taking an exam.

Energy-Star: Energy Star is an EPA (Environmental Protection Agency) rating program for energy-efficient consumer products such as computers, electronics, appliances, lighting, heating and cooling systems, and new homes. Products with the Energy Star label “generally use 20–30% less energy than required by federal standards.” A product can be Energy Star Certified after meeting energy efficiency standards and having it tested by a licensed professional (testing is paid for by the manufacturer of the product).

“On-Site” Solar Electricity and Home Design

“On-Site” Solar Electricity and Home Design

This week I met with a solar electricity specialist and I just wanted to put in a good word his business. I am learning more about sustainable energy technologies and energy-efficiency so that I can better integrate these technologies in to my home designs. A home design that incorporates passive solar strategies, radiant heating, solar arrays, solar hot water, and other energy technologies will result is a more energy-efficient, more affordable, and more aesthetically pleasing/interesting home. I spent some time with Al Borrego, the owner of Del Sol Technologies . Al is an energy specialist that contracts and installs solar panels in the Southwest Montana region.  I talked with Al for over and hour and he was invaluable at answering a whole slew of questions I had. Some of my questions were:

1.  What is the optimum angle of a fixed solar panel array in Montana?
Al: (paraphrased) This depends on if you are hooked to the grid with a reverse metering system or if you are installing to an off-the-grid battery storage type system. If you are installing an off-grid system, you will be needing to harvest the most energy during the short days of Winter where lighting is needed for longer periods at night. The sun angle is lower in the horizon, so the panels need to aim at roughly a 45 degree angle to get the best energy gain. This energy is stored in the battery array for fairly immediate usage.

If you are installing a solar array that will be hooked to the electric grid, it is better to look at maximizing your gains on the long days of summer. What energy you harvest during the Summer will run back through the meter and the local power company gives you credit which can be spent throughout the year (“net metering“). In other words, rather than storing your energy in batteries, you are saving it as future electricity credit that can be used during lower energy-collecting days in the Winter. This array will want to be tilted to favor sun angles that are more overhead, as the sun angle is steeper during the Summer. A 30 degree angle will achieve this maximization.

These types of decisions about sun angle and its projected energy are similar to passive solar design.  It is all about knowing when you want to achieve gains and how to set up sun capturing to favor the gains.

2.  Why are solar panels not integrated into the architecture of a home’s design from the beginning?

Al: (paraphrased) Unfortunately, solar electricity is often considered an item that is at the bottom of a home’s requirements. If there is still money left after the building of the home, then solar panels will be added.

We both agreed that this is unfortunate decision making and brings up many questions.  For one, shouldn’t energy creation on site be considered an asset valuable enough to not consider as an option?  If the home could harvest energy and turn it into power needed to run appliances, lights, etc, why not consider that as important, if not more important, that having an extra bathroom (which often costs about as much as the whole solar array)?

If the solar systems are designed into the home from the start, their installation would be smoother, more seamless, and would be more aesthetically-integrated into the home design. We both agreed that if a collaboration between designer and energy specialist were initiated from the onset of the home design, the overall cost of the installation would most likely drop. Installing solar panels after a home has already been designed and built always requires modifications in mounting. The arrangement of where the solar array is positioned might be difficult to access for installation and repair or to free of snow.  All of these issues could have been considered if solar panels were designed into the initial home design.

Al and I agreed that solar collection systems should be given as much consideration as other aspects of home design. Home energy technology and design should come first or the home doesn’t function correctly. Unfortunately, we are living in a system that has run off of fossil fuels for so long and this is a habit that is hard to break. The future of habitation, however, is with a more self-sufficient home that can create all of its own energy. Like Al said, with energy-efficient appliances, modern solar arrays, and an integrated home energy design, there is no reason why every home can’t completely cover its energy needs. Its just a matter of time before it is common place to see homes being built with such an integrated approach.

Why Passive and Active Solar Design? – Part 1

This is why new homes should have Passive and Active solar design integration

Homes over the last 70 years have been built to rely on the grid system. Big Utility companies or corporations have had a bonanza with making home builders think this way in order to gain a monopoly on energy sales. However in order to move into an energy independence mode we need to rethink this antiquated system. The grid system has many disadvantages today.
The image above is of a liquid solar array on my neighbors home, Adrien Tanguay, who installed this system, he works in this field.

Grid system energy has relied on several factors and lies. Factor and lie #1, cheap energy. Cheap energy is a lie because there is no such thing or “you don’t get something for nothing”. Energy in America has been cheap while it was new in the finding. Coal, natural gas, oil when first tapped were cheap because the extraction was easy, at the surface, and there was lots of it. Today we have misused these sources of energy by overly relying on them and to the point where not only have we hit the down slope on oil well reserves but we have also destroyed huge tracts of land in order to mine and extract these resource. Of course big utility corporations have enjoyed their boom years and have hijacked the way most view energy.

Lie #2 is that energy inexpensiveness has not cost something. We have entered a time period of “Global warming” no matter what the corporations would like the general populace to think. Fossil fuel burning has led to the destruction of our atmosphere and in a very short 200 some odd years. At this time we must slow the singular reliance on these non renewable energy sources. Grid system methodologies hide facts about the dirtiness of their production. Because we cant see the massive energy plants we don’t see the dirt, but our environment does and its sending us some clear messages at this time.

Lie #3 : Grid transmission of power is cheaper than making it locally. Grid transmission is only cheap because of mass numbers of customers, that is what makes it cheap as well as our good old federal government subsidizing such power for many years through breaks to the utility companies. These breaks are coming to the end with the E.P.A starting to send clear signs that stripping coal and new off shore oil wells will not be tolerated. So the resources will become more expensive and utilities will charge more in the future. Cheap electricity has relied on coal. Coal will become more expensive, and the burning of it to generate energy will become more expensive as the EPA cracks down further on emissions standards of carbon dioxide from these plants.

Lie #4: Local power production is unsightly, and noisy. Windmills, solar collectors, and wood burning yes have impacts but so has the grid system. Miles and miles of overhead power lines litter the roads, even woods, fields, and blight the landscape as a whole. At this point most of us just ignore it and don’t see it because who really wants to acknowledge it. I guess we have gotten used to it in the very brief time since its introduction a century ago. But what we do recognize are things that are new…. and wind mills and solar collectors are relatively new… so we see them, but I would argue this is just for awhile… once homes employ their own generation systems they will not be so alien to us. Have you ever heard anyone say “wow those power towers are lovely”?

Lie #5: Local power production is more expensive. Well it is and it isn’t. Much of the expense has to do with local resource availability. Heating by wood stove makes sense in areas that renewable wood sources are plentiful. Wind produces electricity makes sense where there is wind. Solar electric power and passive solar heating make sense where there is ample sun. There are combination of energy gathering systems where the region has a little bit of both. There are other energy sources as well locally available that we do not use due to our dumbed down monolithic grid system energy reliance. The expense often comes in hiring experts to assess the needs of a home in power and which systems make sense in the making of it there on site. The apparati that make the energy usable on-site are initially expensive due to installation and material but the life cycle cost brings this down over time. If our government would subsidize this type of local energy production rather than the corporate energy I would say it would in the end “pan out”.

Grid transmission of energy is fairly inefficient when you look at the losses of energy over the lengths of the power lines or 6.5% in 2007. The infrastructure is also expensive in cost, material, and unsightliness. With increased needs throughout the USA electric transmission can be unreliable found in the form of Black outs. Oil, natural gas all require shipping which is dependent on cheap oil which as we must realize will run out.

Pluses on localized energy production and utilization are that it uses locally available natural and renewable energy resources. It promotes and creates local jobs involved in home energy assessment, installation, manufacturing, harvesting of wood, and design. Using local energy keeps home inhabitants connected to their energy consumption which often promotes energy saving. When home occupants have to think directly about their energy usage they tend to me more frugal whereas with grid type energy and petro/gas utility purchase power it is more abstract by being reduced to dollars. A simple example of this is wood heating, home owners that heat with wood have a pretty good idea of how much wood they need to cut, stack and split in order to make it through the winter and they typically are good at rationing the usage of it. See my blog on radiant heat wood stove retrofit. Oh by the way some might argue that wood burning is dirty… modern wood burning boilers have come along way and do meet EPA standards see this article.
It is easier to make small energy systems less impactive because they dont require train loads of coal. Some might argue that each one of the energy producing systems need to be manufactured. This is true but with simplicity there is less infrastructure, my belief is that it balances out over shipping and grid transport. Also in this same vain your home already has furnaces, meters, wiring, etc its just that its not set up to utilize energy found nearby.

My next blog will deal with passive solar and implementation in the home. See write up here