Photovoltaic systems are costly but can provide 30 to 50 percent of a home's power for 30 years.
With utility rates continually increasing and concerns about the escalating costs (as well as the carbon emissions) associated with fossil fuels, more and more homeowners are considering alternative energy sources to power their residences. “We used to see a lot of early adopters coming in for environmental reasons,” says Richard Deutschmann, Vice President of Policy and Market Development with Chesapeake Solar, LLC, in Jessup, Maryland, “but now we’re getting more typical suburban homeowners.”
You can often save up to 40 percent on energy bills just by insulating better.Michael Barlow with Thermal Loop Corporation in Bel Air, Maryland, agrees, noting that 80 percent of his business in providing geothermal HVAC systems is for retrofits in existing homes. Unlike a conventional heat pump, which draws on outside air for heating and cooling, a geothermal system draws warmth from deep inside the earth via vertical or horizontal pipes that circulate water or environmentally safe antifreeze through a loop under the ground or submerged in a pond. In summer, the system pulls warm air out of the home and puts it back into the ground.
Other homeowners are turning to photovoltaic systems, which use silicon wafers to convert sunlight into electricity. Richard King, director of the U.S. Department of Energy’s Solar Decathlon, uses a combination of passive solar design and a photovoltaic system to heat, cool, and power his home in Charlottesville, Virginia. He acknowledges that he’s looking at about an 18-year payback on his PV system but contends it’s personally satisfying to him to be generating his own energy.
GEOTHERMAL
BENEFITS
• Cost savings. A geothermal HVAC system can save homeowners 30 to 70 percent on energy bills over traditional heat pumps or oil or gas-fired furnaces.
• Almost zero maintenance. Annual service checks and filter changes are all that is needed.
• Higher safety factor than fossil fuel powered HVAC systems because there is no risk of fire or carbon monoxide poisoning.
• No release of carbon emissions into the air.
• Geothermal HVAC systems generally have a life expectancy of 30 years, and most ground loops are warrantied for up to 50 years.
• Retrofits are fairly simple in existing homes.
DRAWBACKS
• Initial cost outlay is usually about 30 percent higher than for conventional HVAC because of the excavation for and installation of the ground loop system.
• Property constraints such as lot size or poor soil may prevent the installation of a geothermal loop system; generally a homeowner needs at least a half acre lot to accommodate the drilling and/or excavation required for the ground loop system.
COST
A geothermal system installed will cost about $25,000 for an average 2,000 square foot home in new construction; a retrofit will be somewhat cheaper, as the homeowner can probably use existing ductwork.
PAYBACK
If you live in a state or locality with good tax credits for alternative energy systems for the home, you can see a payback within three to four years. In Maryland, the state rebate program offers a $1,000-per-ton incentive up to $3,000.
SOLAR
BENEFITS
• Once you’ve made the initial investment in the photovoltaic system, your energy is free; you won’t be subject to rising fuel costs—and because a typical PV system lasts 30 years, you’re essentially buying 30 years of power at a fixed cost.
• You’re decreasing carbon emissions and nuclear waste because you’re minimizing, if not eliminating, your use of electricity from the grid, which is usually powered by coal-fired or nuclear power plants.
• The average three to four kilowatt PV system (generally consisting of five panels) can provide 30 to 50 percent of a home’s power.
• PV systems are virtually maintenance free and can last for decades.
DRAWBACKS
• The amount of energy generated is weather-dependent.
• Expensive upfront investment, though this can be easier to swallow in new construction if you roll it into your mortgage; solar hot water heating offers a less expensive and quicker payback option.
• The orientation of your house is important. You need a generally south-facing, open rooftop for the PV panels.
• Some people do not find PV panels aesthetically pleasing, though many of today’s panels look almost like skylights. Solar shingles are available but are significantly more expensive.
COST
A residential PV system will run from $25,000 to $35,000 installed, depending on the size of your home and how much energy you need.
PAYBACK
The payback depends on the tax incentives available in your state or locality but can be as little as five years, though the average in Maryland is seven to nine.
WIND
BENEFITS
• Economic security. Because typical residential wind systems last 20 years, you’re getting energy at a known price for at least 20 years.
• No carbon emissions, and whatever energy you produce is that much less being drawn from the power plant. Over the course of its life, a typical residential wind system can offset 1.2 tons of air pollutants and 200 tons of greenhouse gases.
• Control of your own power. You reduce, if not eliminate, your dependence on outside sources for energy.
• In a windy area, systems can produce more than 10,000 kWh of energy per year; if your energy provider gives credit for excess power put back into the grid, a wind system could possibly provide all the power for your home and then some.
DRAWBACKS
• Local sites may be inadequate due to tree coverage or lack of sufficient wind; you need to have consistent wind from six to 40 miles per hour for a typical residential wind system.
• Energy output is dependent on weather conditions.
• Not everyone will consider a wind turbine aesthetically pleasing. Most are erected on 30- to 100-foot poles with blades up to 25 feet in diameter. Local ordinances that may prohibit installing a wind turbine on your property.
• A wind turbine will generate noise, which some people may find objectionable.
COST
A typical 10-kilowatt residential wind turbine system can cost as much as $48,000 installed; a general rule of thumb is that small wind systems cost from $3,000 to $6,000 for every kilowatt it is capable of generating.
PAYBACK
With federal, state, and local tax incentives as well as credits for excess power from your energy supplier, a residential wind system could pay for itself in 10 years.
And a handful of homeowners are turning to residential wind power. The most common systems consist of a three-blade turbine mounted on a 30- to 100-foot pole that can provide supplemental power to the home, and sometimes full power if a resident has a power company that allows net metering.
Keith Bennett, Manager for Renewable Energy Projects with the Department of Energy (DOE), says the decision to use an alternative energy source is really about personal choice. “It may work out that the investment in the energy source versus the payback is a wash,” he notes, “but given the power prices, we don’t think that’s going to be the case.”
Carl Seville of Seville Consulting, a green building advisory firm in Atlanta, Georgia, advises homeowners to be thoughtful and do their homework before investing in an alternative energy system. “People find solar panels sexy and want to use them,” he says, “but if you don’t make your home as efficient as possible, a PV system is a waste of money.” He argues it’s often a better investment to concentrate on thoroughly insulating your home and sealing up air infiltration rather than using alternative energy sources. “You can often save up to 40 percent on energy bills just by insulating better,” he says.
Tax Credits
In February, President Obama signed into law The American Recovery and Reinvestment Act of 2009, which has significantly increased tax credits for residential energy efficiency improvements, including a credit for up to 30% of the cost of geothermal heat pumps and solar panels. The Residential Energy Efficiency Tax Credit has also been raised from $500 to $1,500. For more details, visit www.energystar.gov. Many states offer tax credits as well. You can see a full list of the tax credits and net metering options available in your state and locality at www.dsireusa.org. Sometimes these credits can substantially offset the costs of installing an alternative energy system in your home.
Deborah Huso is a regular contributor to ChesapeakeHome. She writes frequently about green home innovations.
Contacts:
Chesapeake Solar, LLC: chesapeakesolar.net or 443-733-1221
Geothermal Heat Pump Consortium: geoexchange.org
Seville Consulting: sevilleconsulting.com or 404-597-7782
Solar Energy Industries Association: seia.org or 202-682-0556
Thermal Loop Corporation: thermalloopcorp.com or 410-879-3588
