This system designer tool is made in Microsoft excel. Give it a minute to load.

Put the cursor over the graph area, and scroll to move the designer page up or down.

Type your values into the peach yellow colored cells or the flat grey cells in the designer.

The yellow cells are drop down menus.

The cells with ones and zeros are switches to turn on and off parts of the graph.

The first narrow table at the top named [Utility Rates] is for writing in your utility rate, so have have numbers to compare your solar system against.

The table name [Electricity Budget] is where you can write in your electric usage for each month to get your cost per month, and see how your usage changes throughout the year.

To the right of the table [Electricity Budget] is a graph showing the overview of your yearly electric profile.

• orange is your usage

• blue is what your system makes

• red is months where you are running a production deficit

• green is months where you are producing excess power

• The blue line is what what system produces on average over the whole year

• the gold line is what your home consumes on average over the whole year

• the green line mark levels of highest and lowest consumption during the year

The main requirement in designing a system is to put enough panels on the graph for the blue line on the graph to be higher than the yellow line.

If you can do that, and have the yearly price come out equal to or less than what you pay right now the the grid, then you are a golden candidate for an solar power system install since you will have nothing invested up front in the system at all and you break even immediately on the bill replacement.

If it's within 30% of your current yearly payment and you pay federal taxes, then you basically still have an investment free solar system once you get your tax return.

Solar will always beat grid power in the long term since it's a fixed payment yearly versus an escalating payment.

If your system somehow looks to be more than that then the main question will be how long will it take to break even.

Since the utility prices go up every year, it might be sooner than you think.

If it's within an election cycle then you're still in a really good spot to go forward right away.

If it takes longer than that and you sell the home early to leave, you might overpay a little bit relative grid power if you got an expensive system. You can calculate out the difference and see if it's small enough that you would be comfortable with that.

Homes with solar systems tend to be valued higher and sell for about 4-5% more overall.

Check with Zillow for current trends and see if you still can't turn a profit on installing a solar system even if you sell the house early.

Homes are appreciating in value at such a high rate that if you sell the house, it might not even matter if the solar system came out a little more than grid power. The appreciation will most likely be well in excess of any difference might have paid in self generated electricity.

Below the area with the main graph are the sections for selecting the equipment that you want to use. Select the model of panel that you want to use. The drop down menu is cluttered, but designed for you to scroll down until you find a model of panel who's pallet quantity will cover your home's yearly electric usage. The panels are sorted in cost per watt so the first model that you see near the top of the list would be the cheapest for your particular situation. Further to the right in the description of the models in the drop down menu are the values for other things that might matter to you, such as the weight, size, facing, longevity and wind or snow resistance of each model. Most panels are standard quality and similar in specs, code-compliant and good enough overall so unless you know you want something more specific, then go with the cheapest one. There are no bad panels included in this menu. Only decent, good, and better. Inferior, hard to obtain, or super expensive panels have all been excluded.