Renewable Energy

renewable energy Renewable Energy is energy generated from natural sources such as sunlight, wind and geothermal heat, which are renewable or naturally replenished.Home Doctor of America are big supporters of renewable energy. However, through our “Whole Home Performance Check Up” it is important to first identify your waste then to reduce and conserve your energy use.  Then we  can accurately calculate which solar or wind sources will best balance out the remainder of your energy consumption.

Solar Power

Photovoltaics, commonly known as PV, converts the solar energy in sunlight into electrical energy with a system producing no air pollution and using almost no moving parts.  They are extremely reliable with a 25 year warrantee and a 40 year design life.

Solar modules, groupings of special silicon cells, produce a DC (direct current) electrical charge when the cells are struck by solar energy. The DC current is routed to a device called an inverter that changes it into the AC (alternating current) electricity required by most household and business applications.

The result is a clean and reliable energy alternative for either residential or commercial use.  A PV system can be integrated into a new construction project or installed on an existing building.  Typically, PV modules are mounted on rooftops but they can also be mounted on the ground, on a nearby roof such as a shed or detached garage, or even incorporated into a shade structure.

PV systems used to power buildings fall into four basic categories:

“Grid-Tied” or Grid-interconnected PV systems are the most popular and use special inverters to allow electricity to flow safely back into the electric grid.  When solar power is generated, surplus electricity can actually flow back into the grid after the power for the building is used.  Depending on your utility company, you can be given up to full retail credit per kilowatt-hour.  Since there are no batteries, these systems cannot store energy and are designed to shut down if the grid is down for safety reasons (mainly to protect utility line workers).

“Grid-Tied” or Grid-Interconnected with Battery Back-up systems offer customers continued power when the grid goes down, while still being connected to the grid for seamless power.  Newer systems also accept other power sources, in addition to PV, such as wind or even traditional gas-powered generators to provide power and/or charge the battery at night and/or if the grid is not available.

“Off-Grid” PV systems are used when a completely independent or “stand alone” system is needed. Since no grid power is used, the system must be carefully designed based on power usage, peak demand and seasonal solar variations. Batteries are typically used to provide power at night, in low sun or high electric demand conditions. These systems are ideal for remote locations where no utilities exist.

Utility-Scale PV systems, sometimes called “solar farms” provide power for regional users by (or in cooperation with) electric utility providers.

Regardless of PV system or metering, most homeowners should install a solar hot water system along with the PV system.  Why both?  Because a solar hot water system is significantly more cost-effective and requires a fraction of the roof space to create the equivalent amount of energy to heat water.  This will also allow the PV system to satisfy a higher proportion of household electric demand, making the PV system even more cost-effective.

Take advantage of generous solar financial incentives – Two sources combine to help you pay for your house’s photovoltaic solar system.  The federal government gives a one time tax credit equal to 30% of the total cost of the system.  There are also a rebates from utility providers that can be as high as $1,550 per installed kilowatt!

Solar Thermal (Hot Water)

A Solar Hot Water (or “Solar Thermal”) system can provide as much as 70-80% of your hot water needs for the year, greatly reducing the portion of your utility bill that relates to water heating, usually natural gas.  If the water heater is electric, the money saved is even greater.  A full-size system will typically provide all the hot water needed between March and October.

Although the basic technology has been around for a number of years, recent improvements make today’s solar hot water systems more efficient, reliable, and durable than those of the past.

A typical domestic solar hot water system uses two 4′ x 8′ flat plate “collectors” which are installed on the rooftop of a home or business (but can be located on the ground).  These flow to a hot water heater, which is used as a storage tank and for back-up heat during the cold months of the year.

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General Types of Systems

Hot Water systems are of two general types.

The first, potable water is passied through tubes and heated by the sun before flowing into the storage and heating unit.

The second type, non-toxic glycol circulates through the tubes, heated by the sun and flows to a heat exchanger where it heats the water.  A back-up heater provides any additional heating of the water.

Spa systems and pool systems function in a similar manner.

System Sizing

Domestic Hot Water – Generally, domestic hot water systems are sized according to the number of people in your family. Typically, two 4 ft. x 8 ft. collectors and a 120 gallon storage tank is sufficient for two adults.

Swimming Pool – Pool Systems require that solar collectors have a combined surface area equal to 50 – 70% of the pool surface area, with “glazed” type collectors being the most efficient.

A solar system for your home may not be as expensive as you think – The ever diminishing cost of technology, coupled with the generous financial incentives have made solar the most affordable its ever been. While a system that completely eliminates your entire electrical bill is ideal, a partial system can offer nearly the same savings but at a fraction of the cost.  No matter what type of system you want, Building Doctors can answer any questions you may have and install any system you prefer.

Wind Power

wind power

Wind power is a very reliable and powerful source of renewable energy and extremely cost effective on a large scale. Residential and commercial equipment are starting to emerge. Please contact us if you have any questions or interest in wind power.



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