Millennium 3 Energy - The area's premier choice for design and installation of Solar Photovoltaics (PV) systems and solar panels
301-745-4180. 17907 Garden Spot Drive, Hagerstown, MD 21740
Google Plus Like us on Facebook Millennium 3 Energy, Contractors  Solar Energy, Hagerstown, MD



What basic factors should I consider before I investigate a solar photovoltaic (PV) system?

OK - the real basics… Do you have a flat roof or a sloped roof that faces south or almost south?  Is much of the roof unshaded for most of the day?  Is the roof in good condition?  (Or in some cases a PV system can be mounted on the ground.)  

How does solar work?

That's a big one... and actually a physics question.  There are good sources on the internet for learning this.  Here is a good one from the National Renewable
Energy Lab:  PV intro by NREL.  In short photons from the sun knock loose electrons present in a solar PV panel, and the panel is designed to gather those electrons and give them a circuit on which to do work, i.e. make electricity.

Do all solar panels make electricity?

No. There are systems with solar collectors that heat water.  These can provide hot water for a home, business, or even a swimming pool.  Ask M3E about these systems, too!  A solar collector can be made to heat air, water, I guess just about anything.  Systems that heat things rather than make electricity are called solar thermal systems.

Do I need batteries for a solar PV system?

In most cases, no.  A typical PV system whenever possible is tied to the utility grid.  When it's dark or the solar system is not producing enough power, whatever is needed comes from the utility company.

How long will a PV system last?
Your PV system will operate efficiently for more than 25 years. A PV module has an expected lifetime of over 30 years.  The inverter may have to be replaced once or twice during the life of the system.

How much can I save if I put in a solar PV system?

Solar PV systems are "scalable."  For each particular project a system size (and therefore capacity) is determined by such things as how much space, how big a budget, and how big an electric bill you have to begin with.  So, you put in a smaller system; you save some.  You put in a comparatively larger system; you save more.

What is "Net Metering?"

At the times the solar system cannot provide enough power for your building load (nighttime, for example) kiloWatt hours flow through the meter and in to your building from the utility company.  When there is light and the solar system is making more than enough power for building needs, electricity flows out through the meter and onto the grid.  The meter nets together the kilowatt hours that come in with the ones that go out.

How much maintenance is required on a PV system?

PV systems require much less maintenance than conventional generators. The panel collectors are typically guaranteed for 25 years or more and require no maintenance.  The inverter life is typically at least 10 years.  The most common cause of problems is a failure in the electronics - the inverter, and overcurrent protection components.  If the installation is done well, these will serve for a very long time as well.  If you think you should test certain of these occasionally, get an expert and never test an electrical system alone.  Think safety first, and always.

What about PV system availability?

For a PV system, availability involves some uncertainty because of the variability of sunlight.  If there is light, the PV system will produce.  System design uses an estimate of the average amount of sunlight at the installation to calculate an annual output in kilowatt hours.

For safety reasons, if your local utility grid is out, a grid-tied solar PV system will shut down as well.

What happens if it's cloudy or rainy, or the system becomes snow-covered?  What about at night?

If you are grid-tied (most likely), the power you need comes from the electric company at these times. 

What incentives are offered for installing a PV system?

Incentives differ for residential, commercial, non profit, and public properties.  The best way to check out current incentives is to visit

How long does it take to have solar PV system installed?

Of course, this depends on the size of the system.  For a "typical" sized residential system in Washington County MD (every jurisdiction has its own rules) once a contract is signed the schedule would be something like this:  Structural Engineer review of the roof - 2 weeks; Permit from the County - 2 weeks; Final design, material ordering, etc. 2 weeks; construction of system 3 weeks; utility interconnection 1-2 weeks.  So from start to finish... about 3 months.

How much does a solar PV system cost?

Of course, this depends on size, type of roof or ground mount, degree of difficulty to tie to the existing electrical system, etc.  Systems are generally expressed in terms of cost per Watt.  A Watt is 1,000 kilowatts (kW).  Here are some price ranges you could reasonably expect:

3 kW to 15 kW Residential PV system:  $2.75 - $4.00 per Watt

30 kW and up Commercial PV system: $2.50 - $3.50 per Watt

Costs have steadily been coming down.  These are as of July, 2013.  And remember, this would be total cost before grants, tax credits, etc.

Lighting and Lighting Controls

What am I looking for?  How do I know if my building is a candidate for lighting improvements?
Look around…

  • Do you have fluorescent light fixtures? T12's are those "fat" (1 1/2" dia.) fluorescent bulbs. They are old technology and should be replaced.
  • Do you have lights on when they are not needed?
  • Do you have a warehouse or similar area with high bay lights over 5 years old?

How much can I save if I upgrade my lighting?
Determine the percentage of your electric use that can be attributed to lighting. For most commercial facilities, lighting is responsible for between 20 and 50 percent of the electric bill. If you implement energy-efficiency practices that reduce your lighting load by half, your bill will see a cost reduction of 10-25% percent.

Is there financial assistance for a lighting project?
For commercial buildings, you bet. There is an energy efficient buildings tax deduction from the federal government, and there are utility incentives in some areas.

How can I instantly reduce my lighting energy use?

  • Turn off non-essential and decorative lighting, especially in unoccupied areas.
  • Replace flickering, dim, and burned-out lights.
  • Clean fixtures and diffusers (at least annually).
  • Turn off lights when not needed.
  • Use task lighting to directly illuminate work areas reducing the need for general lighting.
  • Replace burned out lights with lower wattage lights where practical.
  • Schedule janitorial services during the day, or use fewer lights when cleaning.
  • Color-code switches that should remain off when janitorial crews are cleaning.


Should I consider buying a wind turbine?
A typical wind turbine is installed on a tower high above nearby buildings and tree lines, and must respect zoning laws.  Wind systems are seldom suitable for urban or most suburban locations.  Do you have a few acres?  Wind speed is the thing -- something over 8 mph and sustained is desirable.

How much can I save if I have a wind turbine?
The amount of money a wind turbine saves you depends upon its cost, how much electricity you use, how much wind you have at your site, and other factors.

What kind of maintenance do wind machines require?
Regular maintenance over the life of a wind system is important.  Most small wind turbines have few moving parts and are designed for a long life (20 - 30 years). However, wind turbines do vibrate, and parts must be inspected, maintained, and occasionally repaired.  Experts recommend a routine 6 month maintenance interval.

Are there incentives for installing a wind system?
The best way to check out current incentives for wind systems is to visit

Backup Power

Should I consider getting a back up generator?
Consider?  Yes.  But it's a case-by-case decision.  The way we live today is more and more dependent on continuous and stable electric power.  In some cases generators are seen as a necessity.  Natural disasters such as storms and floods result in blackouts– some for more than a week – and there is a growing awareness about the critical role played by backup power in disaster recovery.  I guess the best way to look at this is:  How much chance is it that your power will be out for awhile, and how serious would that be to you.

How do I decide on which generator?
First of all, hire a pro.  Then get a generator that is rated for the amount of power that you will need. Will you need to power lighting, appliances, and heating/cooling equipment?  A professional will be able to size a generator appropriately for your home or business.

What kind of maintenance do generators require?
Depending on how often power goes out the engine oil and filter will need to be changed once per year or more.  Other maintenance requirements will be spelled out in the owner's manual.

Other Energy Questions

Electric Supplier choice
Customer Choice is a program which allows electric customers to choose the company that supplies your electricity. In MD the Public Service Commission keeps a list on their web site of legit suppliers in Maryland. If you've never chosen a supplier, your local distribution company is your supplier.

My house is inefficient, what can I do?
Whew. That's a big question. Actually, there are lots of things to do. Check out This site is loaded with energy savings ideas. Some actions are free or cheap. Start doing them now. Others require some expense and often involve hiring a professional. If you're serious, get to it! Tax credits are available for certain energy efficiency installations. Be sure to check out that feature on the Energy Savers web site.

I want to get completely off the grid, what can I do?

  1.  Make your building/house as energy efficient as possible.
  2. Install an alternate energy system (solar, wind, biomass, etc. or a combination).
  3. Include batteries/storage with your energy system.
  4. Be prepared for the rigors of maintenance and repair.
  5. Be proud to be an energy independent.

I'm building a new house/building, what should I do?

  1. The web site has good information for building or remodeling. Choose the tab "Your Home;" then "Designing and Remodeling." Be sure to read the tab called "Whole house approach."
  2. Talk to builders, and find one who can speak the language of energy efficiency.
  3. Insist on efficient appliances, lighting, and heating/cooling system.
  4. Consider how location and orientation would support renewable energy systems (passive or active).