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

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.

Thermal

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.

Solar cooling

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.

Resources

Learn what federal and state incentives are available for solar

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

Homes resources

Learn more about LEED for Homes

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.

See more ways to engage your kids in green living

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.

This article was originally published on Houzz on Feb. 28, 2014, as "How to Add a Solar Water Heater," and is presented here with permission. Read the original article

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.

Related articles

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.

See more ways to go eco-friendly with home decor

Whether you are a current renter or are searching for a new apartment or rental home, you might wonder how you can implement sustainable strategies in a space you don't own. The good news is that there are plenty of simple ways to green your home as a renter, from lowering the thermostat to setting out plants, and if you're looking for a building that's already eco-friendly in design, you'll find that more and more options are coming on the market.

Finding a green place to rent

As green buildings become increasingly desirable in the real estate market, both new construction and adaptive reuse projects are luring renters with energy-efficient features.

Look for properties that offer not only the basics of efficient appliances and lighting within individual units, but also features that benefit the whole community, such as solar panels, amenities for bicycle parking or landscaping that conserves water and uses native plants.

There are plenty of examples of places like this. Atlanta apartment complex Ponce Park recently earned LEED Platinum status for its 305-unit complex, which uses Energy Star appliances. In Watervliet, New York, the Tilley Lofts project also achieved LEED Platinum for their update of a historic warehouse into 62 loft-style apartments. The LEED Gold Goldtex Apartments in Philadelphia run on wind power, and in San Jose, California, Gish Apartments earned LEED Gold for their affordable housing that combines green features with community assistance programs.

The 2015 LEED Homes Project of the Year, The Woodlawn apartments in Portland, Oregon, offers renters a green roof, green wall and a 9,000-gallon rainwater cistern for irrigation in addition to the unit features.

Find a green apartment complex in your area by exploring the LEED project directory, starting with LEED BD+C Multifamily Midrise. You can also peruse online listings in your own locality, such as this resource for New York City apartments that are seeking or have already achieved LEED certification.

Making your current spot greener

Before you sign the lease, you can negotiate with the property owner about making upgrades to the space before you move in, such as installing more energy-efficient appliances, inserting weatherstripping around windows and doors or using low-VOC paint for the repainting that is typically done between tenant occupancies.

Once you've moved in, you can do many of the same daily things that homeowners do to recycle, reduce your energy use and enhance indoor air quality:

  • Consider conducting a DIY home energy audit or bringing in a professional to assess where you're expending a lot of energy, than make adjustments such as turning your refrigerator and freezer to the proper temperature settings, only doing laundry when you have a full load to wash or turning down the heat when you leave for work.
  • Enhance your home's biophilic appeal, as well as its oxygen levels, by adding plants to your rooms.
  • Try home composting. It's easier than you might think, and goes a long way toward reducing landfill waste.
  • You're probably on top of tossing items into that blue bin, but explore other aspects of recycling through donation, upcycling and electronics disposal.

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Floors have a long-term impact on indoor air quality and a home’s look, feel and functionality, since they typically account for the most space in a residence.

Installation and maintenance of flooring can require a large quantity of raw materials, finishes, adhesives and cleaners, but there is a wide array of materials to choose from in today’s market that are environmentally responsible. Finding the right one depends on your needs and aesthetic preference.

To make your decision easier and to help narrow down your choices, here are four factors to keep in mind when looking for flooring material that’s both sustainable and healthy.

1) Think about the raw materials and how they were manufactured.

Your flooring material ideally should derive from a renewable resource, such as wood or bamboo, both of which are made from plants. How wood or bamboo is harvested is important, though, since both can be cultivated in environmentally destructive ways. Look out for ones that are certified by the Forest Stewardship Council

Additionally, consider using refurbished stone and tile recovered from existing structures or recycled/partially recycled materials, such as rubber flooring made from used automobile tires. Although these have associated mechanical energy costs, they require fewer new resources.

Generally, it’s better if the material needs minimal modification during the manufacturing process. Stone, wood and bamboo require the least modification, while cork, ceramic tile, linoleum, rubber flooring and carpet require more energy to manufacture.

Review our buyer’s guide for a roundup of eight types of eco-friendly flooring materials.

2) How much transportation will it take for your materials to get to your home?

Consider using materials that have been extracted or harvested near your home to help lessen the environmental impacts of transportation. (For more, review the Materials and Resources credit category in the LEED v4 Building Design + Construction Guide).

For example, materials such as Asian bamboo have to be shipped from great distances, increasing their total environmental impact and embodied energy costs (the sum of all energy required to produce any goods or service).

3) Consider each room’s use and estimated foot traffic.

If you expect a particular space, such as a living room, to see more use in your household, it might be worth exploring installing a flooring material that’s more resilient and requires less maintenance.

A less durable floor likely will need to be replaced more often. The need to frequently clean and polish a more high-maintenance floor could potentially expose occupants to more harmful chemicals. Stone requires frequent refinishing, while linoleum requires little to none.

Read about USGBC’s web and graphic designer Amy Hedgepeth's experience in choosing environmentally responsible flooring.

4) Think about the material’s installation process and disposal.

Installing flooring could require a variety of activities—cutting, sanding and sealing—that could affect indoor air quality, so it's important to consider what the installation process will be like for your flooring.

It's also worth noting what will happen to the flooring material after you’re finished with it. For example, linoleum, cork and wood are biodegradable or can be burned for energy. 

Explore more flooring articles

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.

Windows, doors and skylights have a big effect on the energy efficiency of your home, as well as providing you with views and fresh air. Check out these blog articles on finding the right ones for your living space.

Learn more about home energy efficiency

It's easy to be more sustainable with how you use and store food. According to the EPA, about 95 percent of our food waste ends up in landfills. You can reduce food waste by buying strategically for your family's needs and storing it properly.

In addition, it's better for the environment and for your family's health to use storage containers that are nontoxic and long-lasting. Plastic bags can take up to 1,000 years to biodegrade. Plastic containers often contain BPA, the risk of which grows when we heat the plastic (as happens in the microwave or dishwasher). 

Buying and cooking

Wasting less food starts with shopping smart. Create a meal plan or list of foods you or your family usually consume in a week, and buy those. If you often end up with more fruits and vegetables than you can use while they're fresh, consider shopping more frequently but in smaller amounts.

Chop up a week's worth of produce items, so they're ready to go when needed—it will make it less likely they'll languish in the fridge and spoil. Take it one step further and prepare entire dishes in advance, refrigerating or freezing them to eat later on.

Learn to adapt recipes or improvise your own, based on what's in the house right now. Use up leftovers and veggies by creating your own soups, salads or casseroles from available ingredients. Who knows—you might end up inventing the next favorite family recipe.

The fridge and freezer

There are plenty of long-lasting alternatives to plastic refrigerator containers. In the mid-20th century, people used glass refrigerator dishes in fun matching sets. They're still around, if you're into the vintage look. Today, you can also store your items in myriad glass, ceramic or stainless steel containers to avoid using plastic.

Freezing groceries reduces food waste and allows you to buy in bulk, but make sure you don't then fill your freezer with items wrapped in plastic. A greener choice would be to use mason jars or empty milk and juice cartons. If you use glass, reduce the risk of cracking by choosing containers that are relatively thick, and allow the contents to freeze before putting on the lid.

Portable snack bags

Many of us are used to packing school lunches or office-to-gym snacks in plastic sandwich bags. But that adds up to a lot of waste, even if you reuse each one a few times. Of course, you can use glass, steel or BPA-free plastic containers for food, but if you want a lightweight option for hauling around all day, try reusable snack bags.

Many companies make cloth snack bags that are easy to wipe clean or even throw into the washing machine. See this article from Kitchen Stewardship for a rundown of some of the options, with photos and reviews of each.

See more quick tips on green household practices