Windows can be both a friend and an enemy to the energy efficiency of your home: They are an ideal resource for harnessing heat from the sun, while at the same time, a potential source of waste, leaking your heated or cooled air and increasing your energy bills. Indeed, your windows are responsible for as much as 20 percent of the energy loss in your home. With a few tips, you can harness your windows’ power without the waste.
We can take few tips from passive solar homes, which are designed to work in harmony with nature by capturing thermal energy through the strategic use of glass and shade. But even without a solar house, you can learn to use the sun as your own personal heater—simply turn it off and on with the use of shades or blinds. Here are a few considerations for easy year-round energy maximization.
Keep out the cold
For insulating your windows in the winter months, one of the best options is cellular shades, which feature pockets that create layers between your snug living space and the chilly outdoors. Cellular shades come in varying levels of thickness: singe cell, double cell and triple cell. The higher the thickness, the better the insulation.
Roman shades with an insulated liner are also good options. According to the U.S. Department of Energy, Roman shades act as both insulation and barrier to the cold air. Adding drapes around shades creates an additional blockage between the cold air and your home.
Keep shades open during the day on windows that get full sun to welcome solar warmth, and close them when the sun sets to create a barrier against the colder temperatures. On windows that don’t get a lot of sun, keep shades closed to protect your room from the cool air that may seep through the glass, and add drapes on top of that for even greater insulation. White and light-colored window treatments filter in some sunlight to prevent a room from feeling too dark and dreary.
Block out the heat
In warmer climates or summer months, shades can still act as a buffer, but in the opposite way: keeping the heat out and the cool air inside. Especially helpful on west- and south-facing windows, shades block the strong summer sun to keep a room comfortable. Blackout shades are particularly effective in blocking out heat and keeping rooms cooler.
Shutters and blinds are also an effective option at keeping heat out, according to the U.S. Department of Energy: “When completely closed and lowered on a sunny window, highly reflective blinds can reduce heat gain by around 45 percent. They can also be adjusted to block and reflect direct sunlight onto a light-colored ceiling. A light-colored ceiling will diffuse the light without much heat or glare.
As the position and strength of the sun changes throughout the day and the year, using and adjusting window treatments strategically in your home will help you maximize their energy-saving effects.
The U.S. EPA has a great resource for homeowners looking to estimate their carbon footprint: the Carbon Footprint Calculator.
This quick online tool covers the categories of home energy, transportation and waste. To start, you plug in your zip code and the number of people in your household. Then, for each of the three sectors, enter your current usage, as well as actions you might take to reduce it in the future, such as adjusting your thermostat or driving fewer miles.
The calculator adjusts as you go, giving you a total compared with the U.S. average for the zip code and number of people in your home. Click "View the report" at the end to see a graphic breakdown of your planned actions and how they translate into reduced CO2 and dollars saved.
On Fridays, Green Home Guide shares green home-related content curated from around the web. If you see a great article on aspects of environmentally friendly home living such as green building, renovation, energy use or cleaning, please send it our way.
Spring officially starts on March 20, and before you know it, it will be time to think about gardening. Green Home Guide has rounded up a few useful articles for you:
- Do you live in a dry climate? Curbed's article about drought-resistant landscaping shares tips for locating your garden site, choosing plants and reducing water waste.
The Missouri Botanical Garden compiled tips on sustainable gardening that include how to recycle plant material and pots and how to incorporate rainscaping features and other water collection methods.
- OneYardRevolution's video "How to Grow a Lot of Food in a Small Garden" offers nine tips for growing more food sustainably in less space:
Become a green home expert with this vocabulary roundup of today's industry buzzwords, strategies and methodologies in the building and design community.
Green homes are energy- and water-efficient, create less waste and are healthier for occupants than a standard home. Looking for more? Learn about their benefits and why more homeowners are working to transform their spaces into more sustainable places to live.
Biomimicry is the study and imitation of nature’s systems for solutions to today’s human challenges. It’s based on the idea that nature has already solved the issues that societies worldwide are grappling with, such as energy and transportation.
Derived from the Greek words bios (meaning "life") and mimesis (meaning "to imitate"), the term "biomimicry" gained popularity following Janine Benyus’ 1997 book “Biomimicry: Innovation Inspired by Nature.” Explore how biomimicry can be applied to building design in “Biomimicry: Designing to Model Nature” by Stephanie Vierra of Vierra Design and Education Services, LLC.
2. Embodied energy
Embodied energy is a common term you’ve likely run across in sustainability or building literature. It’s defined as the sum of all energy required to produce any goods or services, including extraction, manufacturing and transportation.
3. Energy Star
Have you been on the lookout recently for energy-efficient refrigerators, washing machines or lighting? You’ve probably seen the label Energy Star. Energy Star is a voluntary labeling program created in 1992 by the U.S. Environmental Protection Agency to identify and promote energy-efficient products.
Greywater, or gray water, is generally referred to as water that’s been used from showers and baths, washing clothes, and doesn’t include toilet waste, according to New Mexico State University’s College of Agricultural, Consumer and Environmental Sciences.
Although the used water may contain grease, food particles and other impurities, it’s still suitable for reuse and is a good source for irrigating landscapes. Visit Greywater Action’s website to learn more about how greywater can help cut water use.
5. Home Energy Rating System (HERS)
The HERS Index is a scoring system developed by RESNET (Residential Energy Services Network) that’s used to calculate a home’s energy efficiency. The lower the score, the more energy-efficient the home is. A home’s HERS Index score is generated from the results of an energy rating conducted by a RESNET Home Energy Rater.
6. Life cycle assessment
Life cycle assessment is an evaluation that attempts to identify all environmental effects throughout the life of materials, products or buildings. It looks at all processes and associated inputs and outputs, including material extraction and processing, manufacturing, transportation, maintenance and recycling/disposal, according to the LEED Core Concepts Guide.
7. Passive building
Passive building, based originally on the Passivhaus concept, comprises a set of design principles that aims to promote energy efficiency, according to the Passive House Institute US. It uses five building-science principles:
- Continuous insulation through a building’s entire envelope, without any thermal bridging
- An extremely airtight building envelope that prevents outside air infiltration
- High-performance windows and doors
- Balanced heat- and moisture-recovery ventilation and a minimal space conditioning system
- Solar energy used for heating purposes
8. Volatile organic compounds (VOC)
VOCs are carbon-containing substances that can be present in paints, coatings such as varnishes and cleaning products. They can cause headaches; nausea; and irritation to the respiratory system, skin and eyes, among other ailments. Learn more about how you can avoid VOCs in your home.
9. Zero net energy (ZNE)
Zero net energy means that a building consumes only as much energy as it can produce by renewable methods. In the past few years, the number of buildings achieving zero net energy has increased 74 percent as this concept catches on. The state of California has even set goals for all new residential construction to meet this standard by 2020.
Recently released data from the 2017 Sustainable Energy in America Factbook, published by the Business Council for Sustainable Energy (BCSE), shows that energy savings for consumers have been increasing with the growth in green energy sources. As a member of the BSCE, USGBC detailed some of the findings from this research, developed by Bloomberg New Energy Finance.
According to the report, in 2016 U.S. consumers spent less than 4 percent of their overall household spending on energy—the lowest number ever. Green technologies like wind and solar power have increased sixfold in the past decade, and renewable energy now forms 22 percent of our power sources nationwide.
Infographic: Business Council for Sustainable Energy Factbook.
Sustainable energy is the future. Here are the top five ways you can benefit from including it in your lifestyle and home:
1) Reduce your reliance on fossil fuels by driving an alternative-fuel vehicle. Electric cars save you money at the pump while also producing less pollution. Better yet, ride a bike, walk or take public transportation—there are many options to suit your lifestyle.
2) Take advantage of the sun's power with solar energy. Solar panels or thermal collectors can help you convert sunlight into electricity or heat, reducing your utility bills.
3) Get an energy audit before making renovations or home improvements, to see what your baseline is and get tailored recommendations for ways to enhance your property's energy efficiency.
4) Install Energy Star appliances. Machines with this seal of approval require less energy to operate. Refrigerators, washing machines, dryers and dishwashers are some of the items you can use to reduce your footprint.
5) Choose more efficient lighting. CFL and LED light bulbs use a lot less energy than incandescents. And while you're at it, make sure to remember to turn those lights off when you leave the room.
When it comes to green homes, solar energy has gone from being a futuristic innovation to a standard way that green homeowners reduce their environmental footprint and save on energy costs. But if you're just starting the green home planning process, you may be wondering what all the solar energy terms you've heard actually mean.
Take a look at our quick rundown of the kinds of solar energy you can use in greening your home:
Passive or active
Solar energy can be passive, meaning it is accessed directly, such as when sunlight warms a house by streaming into the windows or skylights at a certain time of day. Active solar energy, by contrast, is harnessed and enhanced by mechanical components. An example of this would be a pump-operated solar water heating system.
Passive solar energy.
Both kinds of energy can be used in the same home design—you might have solar panels on your roof, and additionally choose the site of your home to maximize natural daylighting. (See the LEED Building Orientation credit.)
Photovoltaic, or PV, is also sometimes referred to as solar electric energy. Energy from the sun is converted into electricity through solar cells, put together into larger solar panels. These are commonly placed on the roof of a home. The whole system comprises these panels, batteries, electrical components and a mounting framework.
Photovoltaic panels. Photo by Angela Jimenez for USGBC/ContentWorx.
When installing a system like this, make sure you've asked the right questions about its suitability for your needs, and that you find a qualified contractor for installation.
Solar thermal systems convert the energy of sunlight into heat rather than electricity. This technique also uses rooftop flat panels or tubes, called thermal collectors, as well as a pump that delivers heat to a water storage tank. The heated water in the tank feeds into the home's main water-heating system and is accessible when needed by the residents in the home. As a result, the house's boiler or water heater is activated less frequently, and utility bills are reduced.
Photo: REGREEN Evacuated Tube Solar Thermal.
Solar water heating can also be used for space heating, such as through in-floor radiant heating (where solar thermal-generated hot water flows through pipes under the floor). This type of in-floor heating or baseboard heating can supplement your regular heating system, but probably not replace it entirely.
This technology isn't just limited to your home—you can also use thermal solar energy to heat your swimming pool.
It sounds like a contradiction in terms, but cooling your home may also be done through solar energy, using any of the above methods: passive, thermal or photovoltaic. In passive solar, you would use principles of design to minimize heat transfer, such as through cool-roof technology.
Active, thermal solar energy cools when the thermal collectors provide energy to adsorption or absorption chillers (this is mainly used in large buildings, such as businesses). With PV, the solar energy that is driving your electric usage is assisting with the electrical load of running an air-conditioning unit.
Concentrated solar power
Concentrated, or concentrating, solar power (CSP), is one kind of thermal energy. CSP uses an array of mirrors or lenses that concentrate a large area of sunlight onto a small area to create heat for power. This is a large-scale technology employed by power plants. According to the U.S. Department of Energy, one CSP plant can generate power for 70,000 homes.
- Estimate the cost of a solar water heater.
- Learn more about installing solar panels.
- Find out what your state offers related to solar energy.
You've made the big decision—you're going to pursue LEED v4 certification using the Homes rating system. Now it's time to get your ducks in a row.
We offer many resources for LEED project teams to get you started on the right foot. Here are the tools and resources that can help you succeed with your project.
General LEED v4 resources
- LEED v4
- Credit library
- Addenda database
- Pilot credit library
- Regional priority credit lookup
- LEED Online
- LEED v4 education
On Fridays, USGBC shares green home-related content curated from around the web. If you see a great article on aspects of environmentally friendly home living such as green building, renovation, energy use or cleaning, please send it our way.
Getting children involved in green living and enthusiastic about saving energy and resources is easy, when you make it fun. This week, we've rounded up several articles that share resources for families.
- In "Home Energy Conservation for Kids," HomeAdvisor shares an abundant link-list of further resources for teaching your kids about saving energy, as well as activities and games that can make it enjoyable for them.
PBS Kids has a kid-friendly definition on its youth website. "Green Living: The Meaning of Greening" also shares quotes from other young people, journal prompts, recycling tips and games.
- Does your child need a cool idea for a science or design fair project? Classroom has a step-by-step guide to researching and building a model eco-friendly home with green features.
If you're building a new home to environmentally conscious standards, consider using insulated concrete.
Insulated concrete forms (ICF) are hollow blocks or cast panels of concrete that many builders use for creating a home or building that is energy-efficient, soundproof and comfortable. The forms combine an excellent insulating material—expanded polystyrene—with one of the toughest building materials around, steel-reinforced concrete. Insulated concrete blocks are quickly becoming a go-to material for both residential and commercial construction.
Creating insulated concrete
Insulated concrete forms were first created just after World War II, as an inexpensive and versatile building material. The simplest explanation of the forms is that they look and connect to one another—a little bit like Lego bricks. They are very durable, with a range of benefits for home and building owners.
The blocks are made out of three different materials, which are combined on site. They start with the interlocking foam blocks or forms, which are held together with recycled polypropylene webs. The foam forms are available in a range of different shapes and options, including structural panels, flat walls, grids and post and lintel systems.
Then, the different shapes are laid out and stacked to the height of the walls being built. These are filled first with steel rebar for strength. The webs inside the forms help to hold the rebar in place after it’s inserted, to help keep it in the right area. Next, the forms are filled with concrete on the interior, surrounding the rebar and creating a structurally sound building. The exterior cladding material of your choice is installed on top of the foam on the outside of the wall.
On the interior of the home, the plumbing and electrical wires are run right through the foam itself after the concrete has been poured. The drywall or plaster is put over the foam, and the interior walls are finished like in any other home or building. From an aesthetic standpoint, the structure will look exactly like any other; there are no visual differences between a home or building built with insulated concrete forms and one built using more traditional stick building methods.
Advantages of insulated concrete forms
The benefits in performance and comfort from using concrete forms are many. ICF homes are very energy-efficient, because they create a tighter building envelope. In fact, it’s common to see a reduction in energy expenditure of between 25 and 50 percent, which benefits both the environment and your wallet. ICF buildings are also sustainable, using roughly 10 fewer trees than traditional buildings.
ICF homes and buildings are also comfortable to inhabit. Studies have found that they cut air infiltration, which brings in outdoor allergens and irritants, by up to 75 percent, compared to a typical house frame. They also help to reduce sound from the outdoors, so your home is quieter. This type of insulation has also been found to inhibit mold growth by helping to control the humidity levels inside the building, leading to better indoor air quality and more consistent temperatures.
Also, ICF buildings are resistant to damage from hurricanes, tornados and earthquakes. They require no additional retrofitting or reinforcement to help protect them from these natural disasters, which is particularly beneficial for new homes in areas prone to such occurrences. The insulated concrete is also fire-resistant up to four hours, which can provide significant protection for the home interior as well.
Finally, you can use insulated concrete forms to build any style of architecture. The finished structure can be clad in any material as well, including wood, brick, stone, stucco, fiber cement and vinyl. This means you can achieve any design, floor plan, layout or unique building shape, while reaping the other benefits.
Build a better building
ICF technologies have been rapidly gaining in popularity as more people are interested in building homes that are durable, energy-efficient and comfortable—and with more stringent building laws being enacted in areas prone to natural disasters, ICF buildings provide a solution to several different building issues at once. Consider using ICF for your next building project to reap the many benefits that this technology can bring.
As people increasingly build better houses, with more efficient envelopes and lower energy consumption and waste, a greater percentage of the energy we do use is going toward heating water. In fact, in a Passive House and many LEED-certified houses, heating water for residential use is the primary energy demand.
As a result, in Europe, many local and national laws now require that a certain percentage of residential hot water be heated by renewable energy. A solar water heater is one way to meet that requirement without dipping too far into savings or renovating an entire system.
Let’s look at some of the basics to consider when adding your own solar water heater.
Photo credit: Metro Solar; original photo on Houzz.
Project: Installing a solar thermal panel to provide hot water for residential use (either to be used right away or as part of a hydronic radiant heating system), through an indirect circulation system.
I am only going to talk about indirect circulation systems here for a few reasons. Indirect systems use a special fluid in the actual solar thermal panel. This fluid heats up and then passes through a heat exchanger, transferring the heat to the potable water you end up using. These systems are generally more efficient and resistant to freezing temperatures than direct systems. The fluid never mixes with your potable water, helps prevent corrosion in the pipes of the system and can carry more heat with it.
It’s a good project for you if: You’re looking for a system that does not involve intensive home remodeling. A solar water heater can be added to an existing system with relative ease, as long as the installer is experienced in this particular kind of system.
Photo credit: Arkin Tilt Architects; original photo on Houzz.
Who to hire: A specialty plumber or contractor with experience in solar water heaters. Be careful in choosing your installer. This is a system that if poorly installed can cause serious problems (including leaks in your roof). Ask for references and examples of work.
Cost range: Although installation costs differ depending on the project, you should set aside $7,000 to $10,000. That seems like a large chunk of money, but can usually expect to see big savings immediately. The U.S. Department of Energy estimates that monthly bills drop by 50 to 80 percent after a solar water heater is installed. An excellent page on its website can help you estimate initial costs and the payback of a solar water heating system. In the U.S., also check DSIRE, a database of state and national incentives that could help speed up payback.
Typical project length: As long as you don’t have to adjust the structure of the house or add space for the mechanical room (where the tanks and systems are stored), the installation of a solar hot water system and its components shouldn’t take much more than a week, and sometimes less.
Best time to do this project: Any time your roof isn’t covered in snow. Start planning now for an installer to come out to your house when spring hits.
Photo credit: Metro Solar; original photo on Houzz.
What to expect: This is what a typical mechanical room looks like. The large tank is the hot-water storage tank, with the pipes running down from the roof panel installation. Also notice the expansion vessel (the small white tank on the floor). The expansion vessel allows the fluid to expand without cracking the pipes.
There should also be a safety valve (not visible here) that discharges the fluid of the system in case the expansion vessel is not sufficient in an emergency.
Photo credit: Paulsen Construction Services, LLC; original photo on Houzz.
Here you can see the hot-water storage tank on the right, with the expansion vessel on top of it. The red fixture in the middle is the circulation pump, which keeps the fluid moving.
Notice that all the pipes are insulated. The fluid inside the pipes can reach temperatures above 212 degrees Fahrenheit (100 degrees Celsius), so it is essential that the pipes are physically removed from the rest of the system and insulated sufficiently. If the structure of your house is wood or contains flammable insulation, such as wood fiber, you need to pay special attention to the protection and placement of the pipes to avoid a fire hazard.
Photo credit: Solar Hot Water; original photo on Houzz.
Here is a system that shows an integration with a gas burner. Depending on the location, climate and season, the preheated water from the solar panel may not meet all of the home’s hot-water needs. This booster ensures hot water even when the panel has reached its limit.
Photo credit: Aneka Interiors, Inc.; original photo on Houzz.
First steps: Do your research and decide which solar water heater system will work best for your needs. Will you be attaching the system to a radiant heating system, for example?
If you need help getting your head around the situation, ask a green building professional or an experienced architect or contractor for a design consultation. A pro can help you determine which part of your roof is the best location for the solar thermal panel. (It will be oriented toward the equator for optimal solar radiation.)
You can also browse Energy Star–rated water heaters to start getting a better idea of costs before asking for quotes.