Solar Buying Guide

DelphiSun Solar Buying Guide

At DelphiSun, we understand that solar buying can be a daunting task. That’s why we strive to make the solar buying experience easy and transparent for our customers. We provide the simplest and easiest solar buying guide in the industry to help you make an informed decision when it comes to transitioning to solar power. Our ultimate goal is for you to have the confidence needed to go solar with us – or any other provider – but if we were instrumental in your decision making process, then that is still a win for us. Regardless of who ultimately provides your solar system, our mission remains the same: Revolutionize the way people access clean energy by providing a seamless, transparent, and affordable online buying experience.  Let us guide you on your solar journey with the five most important items to consider when buying a solar system. This is our Solar Buying Guide. 


The first item to be very familiar with is how the price of your solar system is determined. Our industry uses a pricing model called Price Per Watt which is commonly referred to as PPW. This amount is calculated by taking the total system price divided by the watts in the solar system being purchased. For example, let’s take an average rooftop solar system in Arizona which happens to be a 10 kilowatt system. To get the watts you take the 10 and multiply it by 1000. The reason you do this is because there are 1000 watts in a kilowatt. This is the math below:

10 kW x 1000 = 10,000 watts

The next thing you need to do is take the price of the rooftop solar system and divide it by the watts in the system. In our example we will use the price of what a 10kW system would cost you from DelphiSun which is $23,500. The math is below:

$23,500 ÷ 10,000 = $2.35 PPW

As you can see the price per watt or PPW for a DelphiSun rooftop solar system in Arizona is $2.35 per watt. This is how you can get to the overall price per watt on any system which will allow you to easily compare pricing quotes between different solar companies. By doing this calculation it will help you ensure you are getting the best price for your solar system possible. We will take this one step further which is to get to the net PPW after you apply the Federal Income Tax Credit. For a bonus example we will also include the Arizona State tax credit as well. The Arizona State Tax Credit is unique to Arizona so when calculating your net PPW if you are not in Arizona please make sure you exclude the last step and incorporate your state credit if there is one. You can find out on this website if your state has an additional credit here. If you are in California there is not an additional state credit for rooftop solar. The steps are below:

Step 1 is to calculate what the Federal Income Tax Credit will be. Keep in mind that you should discuss this credit with your accountant to ensure your eligibility for the credit. The majority of homeowners who go solar are eligible for the Federal Income Tax Credit. 

$23,500 x 30%(FITC) = $7050

Step 2 is to take the gross system price and reduce the gross system price by the amount of the Federal Income Tax Credit. This will get you to your net system price

$23,500 – $7050 = $16,450

Step 3 is to apply the Arizona state tax credit which is a credit of up to $1000. In our example we are eligible for the full $1000 tax credit so we will apply the full $1000 in our math below:

$16,450 – $1000 = $15,450

Step 4 is to take the net system price and divide it by the total system watts which is 10000 watts. Once you do this you will have your net PPW for the system price. 

$15,450 ÷ 10000 = $1.55 rounded up

Many companies only advertise this final number which causes confusion but now that we have clearly outlined how to get the net PPW you will no longer have to worry about whether or not you are getting the best and fairest price for your rooftop solar system. With this math you are now armed to ask very direct questions to your solar company regarding price per watt and are able to compare quotes side by side. Price is very important and getting the best price on your rooftop solar system will give you the best return on your investment but price isn’t the only thing you should be considering when you go solar. The other items you need to compare are the solar panels, inverters being used, the system size, and the financing of the final quote. We will review these items in the following sections. 

  1. Solar Panels

Now that we have tackled the most complex part on how to buy a rooftop solar system we will review one of the most important components of your rooftop solar system which are the panels being used. Many companies do not present the panels upfront and just quote the overall system size. At DelphiSun we pride ourselves on providing our customers with the latest and greatest technology and feel you should know the wattage size of the panels you are purchasing. Typically, lower wattage solar panels represent older technology which is where many solar companies like to operate to save on overall cost. At DelphiSun we have partnered with solar installers to use their exclusive solar panels that are rated at 400 watts. Anything in the 400 watt range is going to be your latest and greatest solar panel technology, if the panels are in the 300 watt range then you are more than likely getting panel technology from prior to the pandemic. Request and require a panel in the 400 watt range. The goal is to always maximize your roof space to try and achieve 100% offset of your utility bill and in order to achieve this you need to optimize your roof space and place as many watts on your roof as possible. With higher wattage panels you give yourself a better opportunity to do this. 

  1. Inverters

The next component of the rooftop solar system that is extremely important to know and understand is the inverter being used on your rooftop solar system. There are two different types of inverter technologies to know about which we will dive into below:

The first is called a string inverter which converts the Direct Current(DC) being produced by the solar panels into Alternating Current(AC) in one central location. In this example you typically have one inverter for your system. An additional inverter could be used if the rooftop solar system is larger than 15kW. In addition to a central string inverter these inverter systems come with power optimizers to help maximize the production of the solar system array especially if there are panels that get shaded when others panels do not. This technology is great because it ensures your solar system is producing optimally on a per panel basis. With this option you are also able to see the individual production of each panel in your solar system. Roughly 80% of our customers go with this option due to the direct relationship we have with SolarEdge Technologies, they are one of the largest inverter manufacturers in the world and due to our volume with them our inverters are co-branded with SolarEdge. Our inverters have one of the best warranties in the industry. 

The other method of converting the Direct Current(DC) into Alternating Current(AC) is from microinverters that are directly connected to each panel on the roof. In the microinverter example there is one microinverter for every panel on the roof. The conversion of the electricity from DC to AC is happening directly under each panel on the roof and then transferred to a combiner box near the main panel of your home. With microinverters you also get panel level monitoring as well as optimizing array performance in the event that one or more panels gets shade. The brand of microinverters we offer are from Enphase Technologies. 

There are basically two brands that control the majority of the residential solar market and they are SolarEdge Technologies, Inc. which focuses on string inverters and Enphase Energy, Inc. which focuses on microinverters. Both are great technologies but at DelphiSun we work very closely with SolarEdge due to the fact that there is better long term efficiency with just one conversion point versus multiple conversion points per rooftop solar system. The other reason we like SolarEdge is due to the fact that newer technologies like EV charging and Batteries pair better with single inverters due to the DC to AC conversion. Batteries in particular require electricity to be stored in DC so with rooftop solar systems it is best to route the excess energy from the roof to the battery without any conversion to AC which is where the strength of the SolarEdge inverter comes into play. The DC electric charge is discharged from the battery to the inverter only once maximizing the efficiency of the energy being produced. When you have a microinverter system the electricity produced is automatically converted to AC and then it is required to convert to DC when it goes into the battery and then it is converted again to AC once it is discharged from the battery. All of these conversions make microinverters less efficient long term when you install batteries which is why we recommend SolarEdge for the long term benefit of your rooftop solar investment. Another very important thing to consider when thinking about adding batteries either now or in the future is which inverter is more compatible with the batteries on the market. SolarEdge is compatible with Tesla Powerwalls, LG batteries, Sonnen, their own SolarEdge battery, and Generac to name a few whereas Enphase’s systems are really only compatible with their own Encharge battery system which does not make their solution as flexible long term. If you prefer Enphase we can do an Enphase system for you but there is a slight adder for the change. To be clear the adder is not because the product is better, it just costs more. One last thing to consider is EV charging. The SolarEdge inverter has the capability to charge your vehicle directly from the inverter maximizing your charging capabilities all in one app on your phone. This is very important when you consider wanting to manage your solar system, battery components, and EV charging capabilities all in one app. Enphase does not have a comparably solution for EV charging at this point but is working on one. We will update this article when one becomes available. 

When comparing quotes it is necessary to understand which of these inverters you are getting. The pricing between these two brands are very similar. If you receive a quote from a solar company and neither of these brands are quoted we highly recommend you do your research on the brand to ensure it is of top quality. Our design professionals can help you with this analysis. Typically pricing should be lower with an alternative brand of inverters compared to SolarEdge or Enphase. At DelphiSun we believe in better technology which is why we choose the name brand of SolarEdge Technologies for our customers. If you prefer Enphase we can do that too, not a problem at all, just know there is a slight adder for the Enphase system. 

  1. System Size

The system size is very important when you are comparing solar company quotes because a 10 kW system will not produce as much electricity as a 15 kW solar system. Another thing to be very careful with is getting the exact system size but system production differs significantly between proposals. If you see this one company is estimating more shade interference than the other one. This is important to understand because system production is the key to maximizing your savings and return on investment. So when looking at system size make sure both are identical and that the production estimate is close between both systems. If they are not start asking why there is a difference. When you work with DelphiSun we will review this realtime using our proprietary design software so you can understand what impacts the production of your system. You will be involved in the design of your system so you know exactly what to expect. 

  1. Paying cash or Financing with a Solar Loan

This is very important when comparing quotes as Cash proposals will typically have a lower overall price due to finance fees that come with the solar loans. Some of these fees can be as high as 30% of the cash price. Yes, 30% which means if the solar system cash price was going to be $23,500 the cost to finance would add an additional $10,071.43 to the contract price making the overall system price $33,571.43. The supposed benefit of these very high dealer fee loans is that you can take advantage of a lower interest rate. It makes sense if you plan on keeping the loan for the full term of the loan and not paying it off early. It is our recommendation to take the higher interest rate with no fees and then pay the loan off as quickly as possible. The sooner you pay the loan off the better your return on your investment will be. When shopping for solar make sure you get the cash price and a financed price with no dealer fees or if you plan on keeping the loan for the full term and not paying it off early go with the lowest rate you can get but be prepared to have a significantly higher system price. At DelphiSun we have all options for you to make this decision easy for you to make. Many of our customers take the no dealer fee option and save their cash for a rainy day. By going with the loan you can pay it off at your pace while keeping your hard earned money in the bank.

These five items are the most important items you need to know when shopping for solar. The more informed you are during your shopping journey the more confident you will be in the solar company you decide to go with. We believe that with all of this information you will go with DelphiSun, we pride ourselves on providing Premium Solar without the Premium Price. We are revolutionizing the solar buying experience and making it easier and more affordable than ever before. Below is a link to our free Buyer’s Guide Matrix that takes these concepts and puts it in a format that will easily help you compare us to other solar companies. Going solar is the right thing to do not only from a savings perspective but from an energy independence perspective. Take the control back and produce your own power with DelphiSun!  

DelphiSun Solar Buying Guide.pdf

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