Get solar electric panels and save up to 50% on your monthly electric bill.

You may be able to install solar panels at your residence and significantly reduce your monthly electric bill, locking in a low utility rate using the sun, a clean green power source.

I created this site after doing research to satisfy my own skepticism. The result was reducing my electric bill in half with $0 investment cost and a fully warranted system, no hassle, no maintencance solar power system. I'm excited to share the answers to frequently asked questions in this web page.

Simply fill in the following form for a free solar assessment showing your monthly savings. I have negotiated discounts with several companies to get installation reduction coupons and an additional $100 in savings. The following information in the form is needed to do a feasibility analysis of your location and to contact you.

Does solar make sense, this FAQ and Howto guide is intended to provide you with information to assist you in making a decision as to whether or not a solar pv system is the right choice for your energy needs and if it offers the potential for a more economical source of electric power. It will raise issues, discuss options, and educate you prior to contacting a residential or commercial solar installation representative who will then guide you on the specifics for your location and power requirements. Don't be overwhelmed by all the information I have provided in this document. You have probably heard and read about solar panels for residential use but you may not know you can now install it on your home with no cost and save on your electric bill. I recommend you lease a solar system rather than purchase one and you can see why in the information I have provided.

I had previously created the site how to read your Itron Centron digital electric meter down to the Watt-hour and analyze your electric usage. This seemed like the next logical step from understanding your consumption, to finding ways to reduce cost, generate electricity using green technology, and analyzing Solar PV (PhotoVoltaic) Systems ROI to help you in deciding if residential solar power via renewable energy technology is right for your home. I was surprised to see how much I could negotiate price and that with no money down I could reduce my electric bill by almost 50%.

Get some great information from our friends at Evergreen Solar - the National Council for Solar Growth, a non-profit

We are like tenant farmers chopping down the fence around our house for fuel when we should be using Nature's inexhaustible sources of energy -- sun, wind and tide. ... I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait until oil and coal run out before we tackle that. -Thomas Edison, inventor (1847-1931)

FAQ Table of Contents

• Understanding your location geographically and on your roof
• Effect on home owner insurance rates
• Cost of systems and ROI
• Lease vs. Buying (20 year comparison)
• Choosing panels
• How it works: Inverters and Micro-inverters
• Layout tools
• Batteries vs. Electric Grid
• Energy monitoring solutions
• Rebates, Coupons, Free Assessments

Solar Deals on PhotoVoltaic Panel systems with analysis on ROI and recommendations on lease, loan, buy, discounts, rebates, referrals, and reference links.

Understanding your location geographically and on your roof

There is a great site to see what your expected production can be based on your geographic location and facing, PVWatts Version 2 NREL performance calculator for Grid-Connected PV Systems. Google has recently created Google Project Sunroof that uses this NREL data for seasonal production and satelite imagery to calculate roof space and solar shade. This tool creates a good first step to understanding your possible production/solar potential. For North America, south facing, which is 180 degrees, would be the best location, followed by east or west with north facing being the worst. A 40 degree roof tilt angle on a south facing roof would be about optimal. In the table below, see some computations using Boulder, CO as an example. You will notice that tilt angle is pretty forgiving and if you have a roof that is 45 degrees off of south you still do better than facing east or west. Optimal is a 2-way tilt tracking system that follows the sun but only makes sense for a ground installed system, not on a roof since full tilt is not feasible and only minor adjustments are possible. The solar radiation (insulation) numbers below tell you the how much production your system will produce on average during a year. The larger the number the higher your production and the cheaper the electricity production will be for your system. For example: A 2.5 insulation number would produce half the amount of a 5 insulation number and therefore require twice as many panels to produce the same amount of electricity.

It should be noted that placing a solar system on your roof provides shade by intercepting radiation that had been hitting your roof and is now absorbed by the solar cells of the photovoltaic system. The result has been estimated to be a 10 degree F drop in attic temperature during the summer.

back to Table of Contents

Effect on home owner insurance rates

Each insurance company handles solar installation differently so contact your insurance agent. If you lease the system, the leasing company will most likely cover the insurance as it is not considered part of the structure of your home. More details later on leasing vs. buying. Systems can range from $30K-$55K and the insured value is based on the replacement cost which is the full value before rebates. Some insurance companies have no additional fees for solar installations but others might. For example, Xcel Energy Solar*Rewards Small Program (0.5kW to 10.0kW) requires that homeowners with residential solar panels have a minimum insurance of $300K. If you have a home insured for $100K you would need to add an additional $200K of insurance to meet the minimum. If you are lucky enough to have a home worth over $300K then you only need to be concerned about insuring the system and not the minimum insurance issue. To give an example of insurance rates where no minimum is required, a $240K policy costing $545 per year would cost $585 with a $30K system and $653 with a $60K system. That is a cost of $110 every year and will rise with inflation.

back to Table of Contents

Cost of systems and ROI

The cost of a system should be relatively constant. Price changes in panels and rebates will have an impact on your purchase price. Below are some key bullets that affect your ROI (return on investment).

• Solar Production of your system - Many of the utility companies provide production incentive rebates. The more your system produces, the more money you get back from the utility company. The production is based mostly on the geographic location of your home, obstructions, direction of your array and tilt angle. See location section. If you are buying rather than leasing, the more efficient your production the smaller/cheaper system you can purchase making your ROI period shorter. For the solar lease option, the ROI will be determined by how good a deal you get on your monthly lease payment. The more your system produces, the more money the leasing company gets from the utility company and the lower rate they can charge you on your lease.
• The installation companies can have a rather high profit margin. For this reason, many are offering large signing bonuses and referral fees. The previous bullet is important in understanding why you might have to pay more than your neighbor for the same system on a lease. When purchasing, these factors do not apply and you should be able to get the same purchase price as your neighbor. Time is a factor as the rebates are constantly changing. Get quotes from more than one company and make sure they know you are price shopping. You want their best price up front so you don't get into a bidding war, unless you like that kind of thing.
• Some examples of numbers for Lease vs. Buying ROI. These numbers are in the ballpark but values will vary based on geographic location, home facing, and how well you negotiate your price. Big thank you to Joe at the Xcel Energy Expert Team in Eau Claire, Wisconsin for going over the math in my initial investigation of this topic. The following is not a recommendation on price as you might be able to do better and you will probably find the e19 a better deal. For comparison of Lease vs. Buying see the next section.

  Assuming you are in Boulder, CO, facing south, with an 18% roof angle, and you get 7.392kW SunPower Solar Electric System made up of twenty-four e18 (SPR-308 Watt Modules), one inverter SPR-7000m with Xcel as your electric company. Based on location the estimated annual production is 11.1mWh. Yearly output degradation of panels is assumed to be around 0.4%. If you fully cover your utilization you still pay $8 to Xcel for line usage and taxes whether buying or leasing.

  Buying Math - All are estimates with some rounding, does not take into account time value of money.
  +$39.7K - materials, labor, taxes, permit fees
  -$ 7.4K - Xcel up-front rebate ($1 per Watt installed)
  -$ 9.7K - Federal Tax Credit (30% of your cost, after Xcel rebate)
  ------------------------
  $22.6K - Net Investment
  -$10.0K - Xcel yearly payout for 10 year based on production ($0.09 per kWh produced * 11.1mWh)
  ------------------------
  $12.6K - Note that you will need to replace your inverter approximately every 10 years, so add that cost every 10 years.
  Calculate how much you will spend for 11.1mWh each year with inflation. Assuming $0.10 per kWh, no inflation and an inverter that does not fail after 10 years ($4K replacement cost), you break even after 11-1/3 years.

  Lease Math - Now you will see why with current factors in Colorado, rebates etc., I like the solar lease so much.
  $84 per month for the lease with no money down, cost is $0.091kWh
  $92.50 per month old cost - 925kWh per month average (production matches utilization) at $0.10kWh
  -----------------
  $7.50 per month you save every month starting your first month. Assuming inflation and the increase in the cost of electricity each year, your savings will be even larger. In this example, it is unlikely that utility prices will drop enough in the short-term and long-term for you not to profit on this investment and you are helping the environment by generating green energy.

  Note: In the lease option I did not want to set overly high expectations. I'll do that now. If you have a great location and you negotiate a great price of $50.50 per month then you are paying $0.0546kWh with a monthly savings of $42 per month. Also economies of scale apply so larger systems will have lower per kWh cost. Savings for both lease and buy can be greater if you take into account rising utility rates over time and multi-tier billing which can be $0.15kWh or more.

  Conclusion: Draw your own conclusions on what you should do. Also, remember you have additional incentives and referral funds you can add to your ROI analysis. Overproduction is not a good idea as you get paid wholesale by the utility company, about $0.03 per kWh, while an Xcel utility customer will pay $0.10 per kWh to the utility company and during summer tier 2 might pay $0.15 per kWh which includes 3.6% in taxes and 3% in franchise fees. Remember to compare prices between companies and that your location and shading greatly influence your price. For example, I have seen people pay $84 per month for 925kWh per month ($0.091kWh) and others with optimum location pay $68 per month for 1,250kWh per month ($0.0544 per kWh).

back to Table of Contents

Lease vs. Buying (20 year comparison)

back to Table of Contents

Choosing panels

There are many brands to choose from and other sites cover these issues in the solar renewable energy technology. The simple analysis is price vs. performance. Less expensive panels have lower production and therefore require more panels. You need to take into consideration which panels offer the best price per square foot of space. Your roof size will also play a factor. If you don't have enough roof surface area to meet your production goals a more expensive panel per square foot might be a better option in the long run. Often the lease option will be better for the higher efficiency panels while buying might be more economical for lower efficiency panels. Panels come in various sizes to fit your space and to resolve configuration issues. For example, the e19 comes in 240w (72 cells), 320w (96 cells), 425w (128 cells)

Below is some information on SunPower which has their own leasing division providing you with the option to buy or lease their products. They also have various efficiency levels to choose from. SunPower is currently the leader in efficiency but again explore different brands and sites that go into more detail on this topic. See rebates and referrals section to save on SunPower panels.

A number commonly quoted is 120Sq ft. (10ft x12ft) per 1Kw which is an efficiency of 9.0%.

100% efficiency panel, theoretical since these panels does not excist, would produce for a 120sq/ft. (11.154 kW)

Note cell sizes are not the same across brands (so that info is kind of useless for comparison across brands but may be useful within brand comparison, for example the SunPower e18, e19, e20)

SunPower Panels

e20 - 327w - 20.1% efficiency - 96 cells (22.5% cell efficiency)- 3.406w per cell - for 120sq/ft. (2.242 kW) (SPR-327NE-WHT-D)
e19 - 320w - 19.6% efficiency - 96 cells - 3.333w per cell - for 120sq/ft. (2.194 kW)
e18 - 308w - 18.9% efficiency - 96 cells - 3.208w per cell - for 120sq/ft. (2.112 kW)

The following are 3 models of SunPower panels and their production.
Dimensions of their panels are 1559 x 1046 mm, 61.39 x 41.18 in, 5 x 3.5 ft. = 17.5 sq/ft.
Therefore 6.857 panels are needed to cover 120Sq ft.
Based on these numbers, a commonly quoted, but outdated panel with 9% efficiency, would produce 146W for the same dimension as the SunPower panel.

Sanyo Panels

HIT Power 215N - 215 Watt - 17.1% efficiency - 72 cells (19.3% cell efficiency) 2.986w per cell - for 120sq/ft. (1.902 kW)
31.4 x 62.2 inch panel

Yingli Solar Panels

YL240P-29b - YGE 240 Series - 240 Watt - 14.7% efficiency - 60 cells - 4w per cell - for 120sq/ft. (1.638kW)
64.96 x 38.98 inch panel

Kyocera Panels

KD215GX-LPU - KD 200-54 P Series - 215 Watt - 14.5% efficiency - 54 cells - 3.981w per cell - for 120sq/ft. (1.612 kW)
59.1 x 39 inch panel

Grape Solar Panels

Grape Solar CS-P-230-DJ - 230 Watt - 14.1% efficiency - 60 cells (17.0% cell efficiency) 3.833w per cell - for 120sq/ft. (1.573 kW)
38.9 x 64.9 inch panel

back to Table of Contents

How it works: Inverters and Micro-inverters

A very short and quick version. Solar photovoltaic panels generate DC (Direct Current) which can be stored to batteries but needs to be converted to AC (Alternating Current) for use in your home and to send back out over the electric grid. The inverter is essentially a power adapter that converts DC to AC and changes the voltage. DC flows in only one direction while the AC, like its name, alternates direction. The inverter takes 12, 24, 48 volts DC and in North America converts it to 120, 240 volts AC at 60 Hertz (cycles per second). These inverters are highly sophisticated and must handle inputs voltages that vary widely based on battery state and production variations of the solar panels. The inverters must also handle output demands based on widely varied utilization - a few lights to running a hot tub and an air conditioning system - while maintaining AC quality within narrow constraints and efficiently with minimal power loss.

Micro-inverters are attached to each panel to convert the DC to AC. They are said to last longer and not need replacement every ~10 years like an inverter. They also allow maximum production per panel. Inverters are designed in lines with multiple panels placed on each line. Each line needs to have the same number of panels or watts connected to them therefore requiring more fun math when designing a system. A common system might have 4 strings/lines with 6 panels per line. Another issue is energy production per line can be no higher than the weakest link; all other panels will decrease production to match the lowest producer. The lowest producer may be a permanently degraded panel or a panel temporarily degraded from environmental factors (dust, leaves, bird, squirrel, snow, shadow from a passing cloud). You might find that a tree, roof, or other obstruction creates shade during certain times of the day based on the sun's location which will reduce the production

An advantage and disadvantage of inverters is one point of failure. If the inverter dies your system goes down but on the positive side, there is just one point for replacement and access vs. each panel. And it should be noted inverters fail without any warning.

back to Table of Contents

Layout tools

There are many tools on the market to assist you in designing your system, choosing the right panels (physical size, watts), number of panels, inverters, roof layout, and more. The following are some tools that designers might use to improve production by identifying obstructions and using the results to produce the most efficient layout and string configurations. This is good information for you to understand how things work but less important if you are not an installer or doing the install yourself.

Solmetric

Solmetric has created a suite of products to assist in the layout of your system. They have the SunEye that will show you obstructions at various places on your roof caused by trees, adjacent roofs, etc. It is similar to the inexpensive fisheye globe with markers for time of day and time of year with the addition of a digital camera, GPS, and compass to collect pictures and data for future analysis. The Design software takes the shade information and uses it for analysis taking into account seasonal blossoming of the trees, PVWatts data, etc. They also have an iSV iPhone solar app which is less accurate but lets you make initial estimates for just $5.

Sample image from the Solmetric SunEye 210 Shade Tool ~$2,000

Sample image from the Solmetirc SunEye PV Designer software ~$400 per year

Sunny Design

Here is another application to help with configuration from SMA Solar Technology which is one of the major producers of inverter technology. Their design tool is free with the idea their tool will help you make better use of their products. It is very simple and does not help with location layout but does help with analysis of wiring and string breakdown.

Sample image from the SMA Sunny Design 2.0 software tool that is free

back to Table of Contents

Batteries vs. Electric Grid

I won't go into this in detail and here is the simple version. Batteries are not currently economical enough to consider for energy production and the environmental impact for replacement, manufacturing, and disposal is yet to be seen. They do make sense for those who are in locations where the electric grid is unavailable or for other reasons one might have to be off the electric grid. If the grid goes down you will still have power if you are not connected and have your batteries. Those on the grid will loose power even if their system is functioning since a safety mechanism shuts off production when the grid goes down to prevent sending electricity over the grid. This is necessary to allow maintenance work to fix issues without fear of being electrocuted by your generator.

For most, batteries are not used and instead being grid-connected allows for using the grid as an external battery to send excess during over production hours and a location to get electricity during under production times. How this works is based on individual states. Some states allow electric companies to charge a fee for sending your excess electric out over their power grid lines and a fee when retrieving electricity from the grid. Other states like Colorado allow for net metering which only has fees for sum total of flows. In these cases, if your meter is zero after a month or specified billing period, you don't pay for all those transmissions. A few final notes. If you under produce you must buy from the electric company the extra amount needed to fulfill your electrical needs. If you over produce they will buy it from you but at approximately 1/3 of what you pay since they pay wholesale prices. Lastly, there is usually a minimal fee for being on the grid. For example, Xcel charges about $8 (with tax) to be connected to the electrical grid.

back to Table of Contents

Energy Monitoring Solutions

Track your energy consumption and solar energy production via your computer with nice graphs. I have listed some hardware devices for comparison and many software solutions exist that make use of the data from these systems. They are all pretty simple and similar. They provide instantaneous consumption and production monitoring known as power (measured in kW) and time based information known as energy (power over time measured in kWh). Data is collected by placing monitoring probes around the cables and data can be collected from the magnetic field disturbance generated around the cables. For under $500 you can track production and utilization of your entire home and even sub-circuits.

Google PowerMeter Software which was retired in 2011.

Using eGauge

The eGauge system is a company in Boulder, CO.
Nice overview of the system. The prices are on the higher range but have more features for installers and capabilities than other energy monitoring systems. The MSRP is $752 but installers will get discounts based on volume that will bring the price down. The question is whether they will pass that on to you or mark it up to MSRP. In the near future I will have a referral system in place and will pass some of those savings on to you. Unlike many of its competitors this system can monitor up to 12 Current Transformers (CTs) which allows tracking many sources (power consumption, production, and various circuits). With the nice number of inputs you could track various production sources - upper roof inverter production, lower roof inverter production, overall consumption, overall production, hot tub, a/c, kitchen fume hood, drier, heating blower, etc. They provide an open API for accessing the data for use in other systems and dashboards. The system can store 16 channels of data at a granularity of 1 minute for the last year and for 30 years at 30 minute increments on the device. Their system also provides chaining to allow large complexes to track individual units in a multi-unit large apartment HOA building that only has one meter for the building allowing for retrofitting existing buildings with an inexpensive way to bill each unit. Whether this may be done depends on state laws.

Live Demo of the eGauge

Using TED 5000

The Energy Detective 5000 from Energy, Inc., a Charleston, S.C. company, is a nice monitoring system focusing on the lower price point and has received major funding from 3M. Their system can handle up to 4 Current Transformers (CTs) to monitor 4 sources (power production, consumption, specific circuits, etc.).
Third Party Apps that make use of data from the TED system. The result is many UI options including smart phone apps.
Sample raw TED XML data
Setting up for energy generation
Check out the live demo

Using Advanced Pulse WattNode - Continental Control Systems

SunPower rebrands the Advanced Pulse WattNode by Continental Control Systems. You can see an overview of the various WattNode products which are geared toward the lower price point market. Very low on features, basic consumption and production monitoring. This company is located in Boulder, CO.

Some information on SunPower's offering

back to Table of Contents

Rebates, Coupons, Free assessments

For reference links to the various government and utility company rebates and tax credits you can check out their websites. DSIRE (Database of State Incentives for Renewables & Efficiency) is a good site for links to the federal, state, local, and energy company programs. With the leasing option most of these don't apply but it is always worth investigating since there are exceptions. For example, Colorado (see Recharge Colorado) has an energy monitoring credit that applies even for leased systems.

I have contacted the following companies and setup referral programs so you can save additional funds on your installs of solar panel systems. Based on my research, I have selected companies that seem reputable and good to work with. I make no guarantee as to their service, especially installers, as they have many offices and employees and your experience may vary. I am stating this to provide full disclosure and help you make your own decision. You should expect the process to take 2-3 months from getting your free solar assessment to installation, connection to the grid, and start of operation.

In coming months I will add additional companies to the list of choices. I have currently only listed SunPower panels but will add other manufacturers in the near future as well. I do like and have myself tried SunPower's new lease deal installed by Real Goods Solar that allowed me to have ROI day one (based on my geographic location, roof facing, obstructions, etc). Send me information about companies you have had good experiences with so I can spread the word. Wondering how I was able to get you these referral discounts? A document from SunRun estimates marketing costs of $2,500 per system and these companies are saving that money by having me educate and send them customers.

Here are the current great solar deals and referral fees as of April 2013. They may change without notice at any time which is why I make no guarantees.

Panel Manufacturers and Leasing

• SunPower - Maker of the most efficient panels, highest production per sq ft, important if you have a space limitation. They are also a leasing company that many of the installers use, see below. They give you $200 if you use their panels in your system. Real Goods Solar and IPS below can install these panels and do the lease so select SunPower along with an installer in the form below. Selecting them below gives you the option of the $200 if you use their panels otherwise you won't get it.
• Grape Solar - Maker of inexpensive panels that you can now get at costco as an entire system kit.
  5kW systems from Costco for $13K Grape Solar 5060Watt Grid-Tied PV Kit - includes mounting and inverter.
  3.75kW systems from Costco for $11.3K Grape Solar 3750 Watt Grid-Tied PV Kit - includes mounting and micro-inverters.
  You need to install it yourself and/or get a professional installer.

Installers

• Real Goods Solar - They give you $599 additional for installing. Operates in 11 states: California, Colorado, New Jersey, New York, Missouri, Connecticut, Vermont, Rhode Island, Pennsylvania, Massachusetts, and New Hampshire. They use SunPower panels and other options. You will get an additional $100 from EcoLocate.Org once your system is installed.
• IPS (Independent Power Systems) - They also give you $0.10/Watt that you install which is $500 for a 5kW system. Operates in 3 states: Colorado, Massachusetts, and Montana. They only use SunPower panels. You will get an additional $100 from EcoLocate.Org once your system is installed.
• SolarCity - They give you $1,000 for installing. Solar City operates in 12 States: Arizona, California, Colorado, Connecticut, Hawaii, Massachusetts, Maryland, New Jersey, New York, Oregon, Pennsylvania, Texas, Washington D.C. (Google has invested $280 million for financing the residential SolarLease option). They use primarily Yingli Solar and on request Kyocera and Sanyo panels. You will get an additional $100 from EcoLocate.Org once your system is installed.

Fill in the following form and select the companies to contact you for a free solar assessment. If you purchase or lease a system you will be doing a great part in helping with green energy, reduce your electric bill, and also get some extra money back.

back to Table of Contents