Archive | Buying Solar

4 KWH PV Solar Output in Rochester, NY

Here is an example equation of what you could expect in electricity production each month of the year from a 4 KW PV solar system in Rochester, NY.

Please assume that there are no problems with shade hitting the solar panels, and that the system is angled ideally towards the sunlight.

The numbers below explain the monthly kwh production, the dollar value of the electricity the system would produce, and a few other solar facts.

Solar PV System in Rochester, NY
City: Rochester
State: New_York  
Latitude: 43.12° N
Longitude:     77.67° W
Elevation: 169 m
PV System Specifications
DC Rating: 4.0 kW
DC to AC Derate Factor: 0.770
AC Rating: 3.1 kW
Array Type: Fixed Tilt  
Array Tilt: 43.1°
Array Azimuth: 180.0°
Energy Specifications
Cost of Electricity:     14.5 ¢/kWh

Energy and Dollar Value Output Details from PV Solar in Rochester:

Month Solar Radiation
(kWh/m 2/day)
AC Energy
Energy Value
2.40      236    34.22   
3.55      320    46.40   
4.13      400    58.00   
4.88      433    62.79   
5.20      457    66.27   
5.67      470    68.15   
5.52      470    68.15   
5.26      449    65.11   
4.90      418    60.61   
10  3.49      314    45.53   
11  2.25      201    29.14   
12  1.93      183    26.54   
Year  4.10      4351    $630.89

These numbers as you can see are not considerable, you won’t be saving tens of thousands of dollars right away, but if you factor in a bit of a larger system, or the very good possibility that your actual electric bill is much higher in cost per kwh, then this system might make sense to you.  Some of the difficult factors in this particular location for solar energy is the relatively low amount of daylight hours on average.  The equation would be entirely different if there were lets say 5.5 sunlight hours per day.  That way the solar panels could operate and produce electricity in Rochester, NY for about 20% more time each day.  If though, the state and federal tax credits are something that you could take advantage of, you might want to talk with one of your local installers to see if they can come up with some creative solar panel financing options for you.

Posted in Buying Solar, New York0 Comments

4 KWH Solar System in Lexington, KY

Here is data that shows the electricity production of a 4 kwh solar panel system in Lexington Kentucky.  Again, we are going to be assuming that there is no shading and the solar panels are mounted at the appropriate angle of tilt towards the sun.

Here is the solar production numbers that could be expected in terms of kwh in AC:
Month Solar Radiation (kWh/m 2/day) AC Energy (kWh) Energy Value in $

Results for Solar Energy in Lexington, Kentucky
Month Solar Radiation
(kWh/m 2/day)
AC Energy
Energy Value
3.23      317    19.34   
3.85      336    20.50   
4.38      413    25.19   
5.28      463    28.24   
5.48      482    29.40   
5.84      480    29.28   
5.51      469    28.61   
5.40      460    28.06   
4.94      417    25.44   
10  4.61      410    25.01   
11  3.36      301    18.36   
12  2.58      245    14.94   
Year  4.54      4793    292.37 

So, if you look at the bottom figure to the right, the $292.37 figure, it would look like a pretty lousy amount of money to be saving in Kentucky for such an expensive 4kw solar system.  And that is true.  That size solar system is going to cost about $25,000 before tax credits or incentives.  But unfortunately, even with taking advantage of all the solar incentives in the state and country right now, the cost of electricity in Kentucky is too low to make it a very wise investment.
If you are very seriously interested in adding some green technologies to your house in Kentucky, it would be a much better investment to start of with some Solar How Water panels to heat your water, and then re-visiting the solar electricity project at a later date when some of the variables might change.

Posted in Buying Solar, Kentucky0 Comments

I’m Retired and I Want Solar Power

Hi Longtermsolar,

I live in Grand Prairie, Texas and use an average of 1550 kw hours per month.

What is ball part figure to go solar?

I saw there are tax incentives by the Feds but this does not help me any as I am retired and would never recover the taxes unless they have a program for retirees where they give rebates. Inform me.

Submitted from the Ask Your Solar Power Questions page of the website.

Response from Longtermsolar:

Hi There retiree.  Thanks for submitting your questions about going solar in Grand Prairie Texas.   Your area of Texas receives about 5.3 average hours of sunlight per day for each day of the year.  This number is the amount of usable sunlight that could power solar panels at optimum efficiency not including any energy loss numbers for flat surface fixed mounted solar panels.  This 5.3 hours number is not accurate if you were going to use an axis mounting solar system(the type which rotates towards the sunlight throughout the day.)

So, with 5.3 hours of sun on average, we can calculate how big of a system you might need.

The math is based off your kilowatt hour usage of 1550 kwh/month on average.

Here’s the math:

1550/30 = 51.66 kwh/ day of electricity use

51.66/5.3 = 9.74 kwh/hour need to be produced by your system during your 5.3 avg daily sunlight hours.

But, since solar panels are rated in DC (direct current) we need to calculate the true system size that would be needed before we can get an estimated solar system cost.

To backtrack the math from AC into DC numbers, we can simply multiply the 9.74 by 120% which would bring us to a 11.68 kW solar system.


I would think a 11.68 kW system could meet your electric needs to produce all of your power via solar assuming there is no shading issues either on your roof or on the ground depending on where you want to install your system.

Right now, I have heard people talking about purchasing solar systems in several places in Texas from local solar installers for roughly $5.75/ watt.  These prices have decreased over the past several years quite a bit which makes the investment better for people like you.  But, the cost would still be VERY large.  Your system equals about 11,680 watts.

The total Top Line before incentives costs would be around:  $67,160.00

Because you do not think you would be able to take advantage of the tax credits in your lifetime, it does not appear to be a great investment financially for you.  Since we did not know who your utility company is, its hard to say if you are eligible for any additional incentives which might make the solar system look more attractive.  But, you can look at the page which lists the current incentives to residential people in Texas here-this page is updated daily.

Submitted from the Ask Your Solar Power Questions page of the website.

Posted in Buying Solar0 Comments

How To Calculate Solar Panels For Daily Electricity Use

calculating solar

So often people ask me how to begin figuring out how much money a PV solar panel system is going to cost.  Come on, it is by far the most common question asked on this website and it has been for over two years now which is how long the site has been around.  So, let’s take a moment and talk about how you can figure out your solar system’s expected costs once again.  The math is really quite simple.

Steps for Calculating Solar Costs to Meet Electric Needs:

Step 1:  Figure out how many kilo watt hours or KWH’s of electricity your house uses on an annual basis.

Step 2: Take that annual number and divide it by 365 days to figure out your average daily kwh use for your home.  Hopefully this number will be something that is less than 50kwh per day.  If you are using more than that, you are consuming more electricity than the average household which is fine, but you should also be thinking of ways to conserve energy if possible.

Step 3: Now, we need to calculate the average hours of sunlight you have in your local area per day each year.  You can use the solar sunlight data page to figure this out.

Step 4: Now that you have some of the main math figures, we can begin calculating exactly how many solar panels you can expect to 100% eliminate your electric bill.

Start with your daily kwh usage number.  We will call that “X”

Next, let’s call your daily sunlight figure “Y”

So,  X/Y= Average KWH Use Divided By Sunlight hours.

That new number is going to be “Z”.  Which represents how many kwh the solar system must produce each hour it is working.

Let’s assume for example that Z= 10 kwh.  That means the system must produce 10 kwh each hour that it has sunlight each day.  That would create enough electricity to eliminate your electric bill and allow you to run on solar alone.  But still, we need to figure out how many solar panels that would be.

Step 5:  If we need to produce 10kwh (10,000 watt hours) each hour we still need to know how many watts each solar panel can produce.  If each 200 watt PV solar panel produces 160 watts of electricity after energy loss is factored in, we can do the math of 10,000/160 to figure out how many solar panels we might need.  This would equal 62 solar panels.

NOTE: Your numbers are likely to be different because your home’s sunlight hours and also your homes annual electricity use numbers are different.  But, the formula above is what you need to use to gain an understanding of how many solar panels are required to eliminate your energy bill.  If you have any questions, please feel free to contact




Posted in Pictures, Saving Money2 Comments

Just Little Solar Energy in Dallas, Texas

Solar Energy has most definitely not hit it off big yet in many parts of Texas.  That is surely the case for one of the largest cities of Dallas.  During a recent visit to Dallas, it became clear after flying over parts of the city that they were not nearly as progressive with putting up solar panels on buildings compared to cities like Austin and even Houston.

Take for example a building which was located very near to the airport.  It appears to have a great flat roof with  absolutely no obstructions to the sunlight, yet there is not a single solar panel installed to produce electricity.  Here is a picture of the Dallas, TX building which needs to have solar panels installed:  building that needs solar panels in Dallas, TX

To the defense of many of the residents and businesses in the Dallas, TX area, there is a very good chance that the lack of solar panels is not because of anything other than economics.  Although the price of labor and solar panels has decreased in Texas over the past five years, the solar investment is still often out of reach for most homeowners and businesses which leads to in-action on solar project ideas.  Another very important factor is the differences that exist even within states in terms of the prices end users pay for electricity.  KWH(kilo watt hour) prices can vary considerably even just a few hundred miles from one spot to another within a large state such as Texas.  When the price of electricity is relatively cheap, it can make the financial case for a solar system even worse.

Hopefully someday in the near future, the price of solar panel will be so perfect, that all of the residents and businesses in Dallas, TX will be utilizing the sunlight in a much more self sustaining way compared to right now.

Posted in Pictures, Saving Money0 Comments

Wind Power vs. Solar Power

wind power compared to solar panels

wind vs. solar

To compare the potential benefits of wind power vs. solar panels in terms of the capabilities to produce electricity, you first need to understand the requirements for both types of renewable energy systems.  They are very different, and both of them come with their own set rules for working properly.  Please note that although is focused and geared towards solar energy, this is an unbiased assessment of both of the two technologies.

Wind Power Requirements:30 ft. wind turbine

  1. Excellent long term wind studies documenting that a consistent heavy amount of wind is present all year round
  2. Ground clearance which will not create a safety problem for the propeller of the wind turbine hitting other objects and of course not hitting another person or animal
  3. Local noise restrictions must be investigated, local zoning laws may prohibit wind turbines in certain locations
  4. Wind turbine maintenance and the long term maintenance schedule should be investigated in great details
  5. Interconnection with the local utility grid to provide the opportunity to sell back unused kilo watt hours
  6. Proper home owners insurance for the wind turbine in case of a tornado or hurricane

Solar Power Requirements:

  1. Excellent sunlight hours
  2. Available roof space with a new roof that can last 25 years or more
  3. Proper angle of the solar panels towards the sun
  4. Professional solar panel installation and connection to the utility grid
  5. Alternate plan for maintenance with several different solar power companies in case one goes out of business
  6. Clearance with the local building inspector or permitting office

Electricity Production of Wind Powered Turbines:

Wind turbines have traditionally been able to produce much more electricity per dollar spent on materials to make the systems.  This has been the case for years, especially with larger scale utility grade wind turbines.  This is the reason why there are so many wind powered turbines in the hills of California and other parts of the United States and world where there is a known wind presence.  Even to this day, it is a very close race and there is still more electricity produced by Wind Turbines in the United States compared to from Solar panels, but this is going to change any day now.

Solar Panel Costs to Install Are Decreasing:

Over the past decade, the overall costs to install solar panels to produce electricity have decreased by over 50%.  This is very significant because it is now considered the most cost effective renewable energy source for producing electricity.  The government funding that has been available for several years makes this clean energy source even more attractive, even when compared to wind power.  The difference with solar and wind power is that many people, especially in urban and suburban areas do not want to listen to the noise that wind powered turbines emit all day and night.  In comparison, solar panels are virtually noise free, and the only thing they emit is some heat and clean electricity.

Posted in Buying Solar, Wind Power0 Comments

Solar Panels Made For Farms

ground standing tilted solar panels

32 solar panels ground mounted at a farm

Farms all over the United States are going green with solar panels these days.  Not only are farmers having to pay through the nose for the high prices of electricity, but overall commodity prices are increasing for most of the other items that farmers need.  But, many of them, like the farmers in these pictures have found some ways to cut corners and reduce their costs on the energy consumption side, while thinking long term too.  The solar industry has been focused on the local farmers for many years, this is nothing new.  With the simple fact that farmers often times are in need of power and electricity that is far away from any electric panel, many farmers developed off grid solar systems to meet their energy needs years ago.

Today, things have become even easier for small and large farmers to cash in on sunlight and the solar electricity it produces, with the invention of grid connected solar panel systems, you don’t even need batteries anymore to make your own power on your farm.  The solar panels from these pictures are actually grid connected PV solar systems.  They simply collect the sunlight all day long, and as you can see there is absolutely no shade to worry about, and they feed the energy back into the electric meter.  When the property is producing more electricity than they are consuming, the meter spins backwards.  The opposite is true when they use more power than they are making.  Overall, the reality of farming is that electricity is needed to run a farming operation in this modern world, and with an abundance of sunlight, farms are an ideal place to have solar panels.


rural solar panels

32 solar panels on the ground


The ground mounted solar system option utilized on this farm works very well for two reasons.  The first reason is the angle these panels have towards the sun is ideal because they are situated at a south-west direction towards the sun.  Also, the angle of these solar panels is setup perfectly and adapted to the ground mounting hardware racks, so the panels can sit at approximately 22 degrees and face the sun at the same time.  This is a 32 panel solar system, and its about 5.4kw in size, so it will be producing a sizable amount of kilo watt hours each month, but not all productive systems need to be this large.




Posted in Pictures, Saving Money, Solar Equipment0 Comments

4kW Solar System Output Data for Newark, NJ

City: Newark
State: New Jersey
Lat (deg N):  40.70
Long (deg W): 74.17
Elev (m):  9

PV System Specifications

DC Rating: 4.0 kW (size of the solar system)
DC to AC Derate Factor: 0.770  (this takes into account the expected energy loss from DC to AC)
AC Rating: 3.1 kW
Array Type: Fixed Tilt
Array Tilt: 40.7
Array Azimuth: 180.0  (direction of the solar panels towards the sun)

Energy Specifications
Cost of Electricity: 11.2 cents/kWh

Month / Solar Radiation (kwh/day) /  AC Energy (kWh) per month /  Energy Value in $
January / 3.36 / 331 / 37.07
February / 4.05 / 358 / 40.10
March / 4.58 /  434 / 48.61
April / 4.84/ 424/ 47.49
May / 5.30 / 467 / 52.30
June / 5.33 /  440 / 49.28
July / 5.27 / 445 / 49.84
August / 5.25 / 440 / 49.28
September / 5.06 / 427 / 47.82
October / 4.46 / 402 / 45.02
November / 3.15 / 287 / 32.14
December / 2.87 / 277 / 31.02

Year /  4.46 /4732/ $529.98

The overall annual production of electricity in Newark, NJ would equate to approximately $529 in value for a 4 kW solar electric system that was without shade.  This number does not represent the overall value the system brings, as it does not include SREC values, and it also does not take into consideration any tax credits or rebates that are of additional value to the home owner who purchases the solar system.

Posted in New Jersey0 Comments

5kW Solar System Electricity Output in San Antonio, TX

Summary of a 5kW solar panel system in San Antonio Texas

City: San_Antonio
State: Texas
Latitude: 29.53° N
Longitude: 98.47° W
Elevation: 242 m
PV System Specifications
DC Rating: 5.0 kW
DC to AC Derate Factor: 0.770
AC Rating: 3.8 kW
Array Type: Fixed Tilt
Array Tilt: 29.5°
Array Azimuth: 180.0°
Energy Specifications
Cost of Electricity: 9.7 ¢/kWh


Month Sunlight Hours/ kwh produced/ (kWh) Energy Value in $
January:     4.20    475   46.08
February:   4.89   495    48.02
March:       5.40   603   58.49
April:         5.46   578   56.07
May:          5.61   608   58.98
June:         5.94   605   58.69
July:          6.50    674   65.38
August:     6.41   669   64.89
September:   5.92   600   58.20
October:     5.63   610   59.17
November:   4.80   517   50.15
December:   4.10   463   44.91
Year          5.41   6899   $669.20

Overall, a 5kW solar system that is installed in a home in San Antonio, Texas is going to produce about $669 of electricity per year with the current electricity costs of about 10 cents per kilo watt hour.  If the prices of electricity increase, the dollar value of the electricity produced will also increase while the rest of the variables stay the same.  If the prices of the electricity for example doubled in price to a homeowner, the amount of electricity in dollars that the solar system would produce annually would double as well.

Posted in Texas0 Comments