Tag Archives: building green

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energy efficient hot water system


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Comparing energy-efficient hot water heaters probably isn’t on your green homebuilding to-do list. But, wait a minute! Water heating is the second biggest expense in your home, and the average family uses 64 gallons of water a day and spends $400 to $600 a year on hot showers and clean dishes and laundry. It’s time to check out the most energy-savvy options available.

Size up the situation
The first thing to do is to figure out your family’s peak-hour hot water demand, and then discuss options with your general contractor. If your water utility offers a free online service to manage your monthly water usage, sign up and use the data to calculate the size of tank you need.

Research your options
Contractors and plumbers understand conventional storage hot water systems, but some of them are not familiar with more sustainable options like tankless (on-demand) or solar hot water heaters. Don’t let them talk you out of using technologies they don’t understand. Be proactive—do your own research and meet with reputable installationcontractors who can help you calculate the right size system for your home and know how to integrate it with the plumbing.

Shop for heating systems
There are five types of water heaters available: conventional storage, tankless (on-demand), heat pump, tankless coil and indirect, and solar.

Conventional storage water heaters
, which run on electricity, natural gas, propane or fuel oil, are relatively inexpensive to install and run. But, they waste energy keeping gallons of water heated 24/7 and lose heat due to lack of tank insulation. New, high-efficiency gas-powered models and gas condensing water heaters (that use heat generated from combustion gases to help heat the water) are more energy-efficient options.

Tankless (on-demand) water heaters, which are powered by natural gas, electricity or propane, heat your water without using a storage tank and are eight to 34 percent more energy efficient than storage heaters. However, they have limited flow rates, which can mean cooler water during simultaneous multiple uses or when there are long distances between the heater and your showerhead. Installing two tankless systems can solve the problem, though the energy savings might not offset purchase and installation costs.

Heat pump water heaters use electricity, natural gas or geothermal energy (heat from the Earth) to heat water. These units are two to three times more energy efficient than a conventional storage water heater. However, they work best in areas where the temperature is between 40 and 90°F all year, and they exhaust cold air. Consult a knowledgeable professional for more details.

Tankless coil and indirect water heaters use your home’s space heating system to heat water and run on electricity, natural gas, fuel oil or propane. Advantages include lower installation and maintenance costs, but they are not a good choice for warmer climates. Talk to an installation contractor for more information.

Solar water heaters, which heat water using the sun’s energy, are fifty percent more efficient than electric or gas water heaters. But, the initial investment is higher, and some people install a backup system (or budget water use) during cloudy days and peak-demand times. Have a solar hot water professional visit your site to see how much sun it receives, discuss system options, and tell you about available rebates and incentives.

Fuel Source, Energy Star
Today’s water heating systems are powered by electricity, natural gas, propane, fuel oil, geothermal or solar depending on the type of heater. Your property location determines which fuel sources are available to you.
After comparing energy-efficient hot water heaters, costs, life expectancy, pros and cons and fuel sources (check out Energy.gov’s helpful infographic), you can decide which is the best choice for your family. As you consider appliances, look for the Energy-Star label — denoting high-efficiency — on gas storage water heaters, gas condensing water heaters, whole-home gas tankless water heaters, heat pump water heaters and solar water heaters. Choosing the right hot water heater for your needs can not only save energy, water, and money, but it can help you enjoy a hot shower with a clean conscience knowing that you are putting less stress on the environment.

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solar panels

Solar Panels Made Simple

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Written by Joyanna Laughlin for Time to Build a Houseplans Blog

Properly oriented solar panels can make a house or cabin energy-independent.

Are you thinking about installing solar panels as part of living a greener lifestyle? Here’s what you need to know from homeowners and experts who have done the homework for you.

Solar panels or photovoltaic? It’s the same thing. What most people call solar panels are the modular, silicon-based, flat-plate photovoltaic (PV) panels that turn sunlight into electricity, says Ben Uyeda, designer, co-founder of ZeroEnergy Design and FreeGreen.com, and director of HomeMade Modern. A solar electric (a.k.a. photovoltaic) system includes a group of PV panels, inverters [pieces of equipment that convert direct-current (DC) electricity generated by a group of PV panels into alternating-current (AC) electricity that can run your appliances], a mounting system and other equipment.

Additional types of solar energy systems include flexible solar photovoltaic films (used on metal roofing systems, boats, recreational vehicles, etc.) and solar thermal systems, which produce hot water to supplement your home’s water heating system, says Alan Spector, architect and owner of Lafayette, New Jersey-based Spector Associates Architects.

Understand your energy usage
In order to figure out how much energy you need to power your home using the sun, you need to know how much energy you use. This means understanding how much energy it takes to do things like heating your home or making a cup of coffee. According to Estimating Home Appliance and Energy Use on the U.S. Department of Energy’s Energy.Gov website, it takes between 1,800 and 5,000 watts to dry a load of clothes, between 1,200 and 1,875 watts to dry your hair, and 900 to 1,200 watts to brew a pot of coffee. Energy consumption has to do with personal habits, says Kirpal Johnson, an energy consultant for San Mateo, California-based solar installation company SolarCity. Leaving doors open and lights on or running the furnace or air conditioning a lot increases energy consumption. Performing a home energy audit can help you to find out what your actual numbers are. There are tools online to help you do it yourself, and there are also private companies, as well as some public utilities, that will do it for you.

Shop around
Once you’ve decided to include a PV system in the design of your new home, Uyeda recommends having your general contractor get bids from subcontractors, and Spector adds that it’s a good idea to compare three bids from qualified installers. Research the installers to make sure that they are legitimate companies, and to understand the contract you are signing. “Educate yourself on the company, and inform yourself about the contract,” advises SolarCity’s Johnson. “Homeowners need to be involved at an active level and engaged with the process and the numbers,” Johnson says.

Check the numbers
The installer you select to design your PV system should provide you with an exact calculation of the amount of energy your system will produce, Spector says. You can verify the numbers the installer gives you by using websites such as the National Renewable Energy Laboratory’s PV Watts Calculator.

Buy brand name equipment
Most PV panels have similar conversion efficiencies (the rate at which the panels convert sunlight into electricity). Make sure that your PV panels and inverters are established brand products with good warranties, says Spector. Uyeda recommends telling your general contractor and installer what you are looking for (including good warranties on the equipment) and letting your general contractor and installer pick the brand. Some major solar panel brands include SunPower, Kyocera, Sharp, Yingli, LG and Canadian Solar. And SolarCity recently purchased Silevo, a manufacturer of high-efficiency solar modules, which means they are getting into manufacturing solar panels, a business that is currently dominated by Chinese companies. And SMA, Outback and Fronius are established brands of inverters.

Solar works in cold climates
Solar systems are not just for people in very sunny places. Solar also makes sense in cooler, northern climates. “The important thing is proper orientation to the sun and the amount of sunlight the location receives,” Spector says. “Germany is the world leader in solar, PV and it has only moderate sunlight.” Spector owns a 3,163-sq.-ft., home in New Jersey with a 5-kw PV system that provides 65 percent of the home’s electricity needs and powers Spector’s electric car, a Nissan Leaf.Uyeda designed his own 1,200 sq.-ft energy-efficient home, which is currently under construction in Boston, and he is having a 4-KW PV grid-tied system installed to provide a portion of the home’s electricity needs and to power his Nissan Leaf — the exact amount depends on how much he drives the car. “If you are building a new home in a cold climate,” he says, “solar shouldn’t be the first thing you think about. Consider the building envelope first (orientation, insulation, and energy efficiency). Don’t spend a lot of money on solar to heat an inefficient home.”

Financing options
There are several options, including buying your PV system up front (which might cost $20,000 or $30,000, says Johnson), rolling the cost of the system into your mortgage like Uyeda is doing with his home, or leasing your system from a large installer like SolarCity. Uyeda prefers packaging the cost of his PV system into his mortgage because the money he would have spent on gas is now going to increase the value of his home, which is a tangible asset. The main benefit of leasing is that you can get a PV system on your home without paying any money up front, Johnson says. Solar City installs the system, insures it, monitors its performance, and handles repairs and maintenance. You sign a 20-year contract with SolarCity, and they take a percentage of your energy savings over the life of your contract. Whichever financing option you choose, going solar can be a simple process and you can soon be on your way to lower energy bills and contributing toward a cleaner environment.

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essentials for building green

12 Essentials for Building Green

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Written by Joyanna Laughlin for Time to Build a Houseplans Blog

The goal for this vacation house in Rhode Island — by Zero Energy Design — was to minimize energy use.

At first, building a new energy-efficient home is all about imagining the best of what’s possible—the hottest design, the latest green technology, and the coolest energy-efficient products. Then, reality bumps into your dreams. Maybe it’s your budget or even the limitations of your building site. To help take the bumps out of the building process, Time To Build asked five architects and designers who specialize in sustainable development and green design to share their hard earned experience on what you need to know before breaking ground.Know your budget
According to Ben Uyeda, designer, co-founder of ZeroEnergy Design  and FreeGreen, and director of HomeMade Modern, the biggest mistake people make is that they design their house twice. “First, they get it costed out with what they want; then, they get it redesigned with what they can afford,” he says. The key is to coordinate the most cost-optimal approach to reducing your home’s footprint while adding environmental benefits.Look at the whole picture
Use a holistic approach in your design process, says Jennifer R Young, AIA, LEED AP BD+C at the firm of Lake Flato Architects in San Antonio, Texas. Consider overall comfort, connection to the outdoors, sustainable material sourcing, healthy products and the highest indoor air quality.

Review project goals
To Nancy Malone, AIA, LEED Fellow, and a principal Siegel & Strain Architects in Emeryville, California, it’s critical to set key project goals, at the beginning of the process, and revisit them frequently. “Review your goals at key milestones, and use them to make design decisions, especially value-engineering decisions,” Malone says.

Understand your climate
Perform a climate analysis early in the design process to help understand the particular weather patterns and sun angles of your site, Young advises. “The more you understand about your site, the more passive strategies you can employ, which gives you a head start on creating a comfortable, energy efficient home,” she explains.

Orient and Insulate
The tried and true methods for building an energy-efficient home are still the best, says Paul Warner, licensed architect, general contractor, and principal of San Francisco-based Sagemodern Inc. These include orienting your house and placing windows to maximize solar gain when you want it and minimize it when you don’t, designing the correct overhangs and other window shading, using the right amount of insulation, and air sealing. Young adds, “If possible, orient your home on an east-west axis, which allows you to minimize the amount of lower/harder-to-shade sun from the east and west, to maximize southern exposure in your heating season (if you have one), and to gain the soft northern light year round.”

There is no green bullet
There is no one-size-fits-all solution to energy efficiency. For example, while the idea that you get more value for every dollar spent on insulation is generally true, it depends on the difference between the temperature inside and outside of your home, Uyeda says. What has a huge impact in Austin, Texas, may not work as well in Santa Barbara, California.

Size matters
Smaller houses are inherently more resource efficient than larger ones, Warner says. As Jonathan Feldman, AIA, principal of San Francisco-based Feldman Architecture, points out, larger homes not only consume much more energy, but they require more materials to build, which also have large amounts of embodied energy. Young agrees. “It’s always tempting to want more space,” she says. “But, think about what you need day to day, and allow one space to have multiple programs.”Warner sums it up: “A compact floor plan with good orientation and good insulation not only saves energy in the long run, but it should allow you to install smaller mechanical equipment.” Make sure your mechanical contractor properly sizes your HVAC system so that it runs at peak efficiency, and you’re not paying for excess capacity.

Don’t believe the hype
You don’t have to buy into a lot of complicated systems or fancy gadgets to achieve energy efficiency. “Keep things simple, and purchase systems and appliances that make your life simpler and are easy to program without costly maintenance,” Young says. Malone agrees. “Our culture has solved many of our design challenges with technological solutions,” she says. “Although many of these solutions offer benefits, we can design energy efficient homes with a set of fairly low-tech engineering principles.”

Ask how they know
Ask your design team what stands behind their recommendations. Uyeda suggests asking if they use modeling software and cost-benefit analyses to determine what’s right for your home. Malone agrees. Energy models can analyze predicted energy performance in a given design, and also model variations such as different wall assemblies, windows and mechanical systems, to identify which elements will be the most—or least—worth investing in.

Know your priorities
Understanding what green means to you, and communicating with your design team is crucial. “If you are looking for a return on your investment, then you should aim to balance your electric load and onsite energy generation (solar, wind, geothermal, fuel cell) with a goal of supplying at least enough energy so that you don’t exceed your utility company’s lowest tier pricing structure,” Feldman explains. “If you want to be net-zero, then that leads to different design strategies.”

Pay attention to your lifestyle
Be honest about your energy usage and habits. If you forget to turn off the lights, a lighting control system, occupancy sensors, or an app on your phone that can turn off your lights can help save energy. Or if you have other specific needs, like cooling a large wine collection or running electronic sound and video equipment, tell your design team.

Solar Strategies
If you’re considering adding expensive features like a solar system to your home, one way to save money is to package the cost with your mortgage. Uyeda put solar panels on the roof of his house, uses them to charge his electric car among other things, and financed the cost in his mortgage.

The bottom line: Understand your priorities and lifestyle, know that there’s no one-size-fits-all way to achieve energy efficiency, and be prepared to communicate your priorities to your design/build team are keys to help you make your dreams of a new green home become a reality.

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