How to choose the best solar quote for your home?

25/2/2019

Going solar is fun if it is done in the right way. The very first step, after you make your decision of going Solar, is to ask for quotes from different solar installers.

Solar Feasibility Spreadsheet

Sometimes, comparing quotes can be a bit confusing and frustrating. But if you keep in mind some simple points then this process can become easy and will help you in choosing the best solar power system, meeting your energy requirements.

Before moving ahead, let me remind you of the important components of a basic solar power system. These are as follows:

Solar Panels
Inverters
Battery & solar charge controller (If you are looking for the battery backup)
Wires and the mounting structures

Your half job is done if you are successful in selecting the right quality components for your system. The job is complete when your selected components perform in resonance with each other. In simple words when the specifications of each component facilitate the performance of the complete system so that it achieves the maximum efficiency in the given conditions.

A quality solar panel

The panels are the first interface between the Sun and your electrical appliances. They convert solar energy into electrical energy. They will remain under blazing sun and harsh weather conditions throughout their life. Therefore, the solar panels have to be durable and efficient in every aspect. You should look at the panel which is made of the best of materials. Generally, manufacturers who understand the material science in making a solar panel durable have accreditation to ISO standards for manufacturing with advanced quality assurance. But do keep in mind the quality of the solar panels and the warranties the brand is offering to you. Initially, a cheap panel may cost you less but will increase the maintenance cost and will become a headache for a lifetime. Therefore, look for those ISO certified brands which have a reputation in the market with good reviews about them. It may be a bit costly but can provide you smooth electricity for decades. If your installer gives the solar quote with the brand name of the panel mentioned in it. Then check its specifications by yourself on the internet by looking for the following technical terms:
Power rating: A higher power rating means that panels are more effective in producing power (Most solar panels are in the range 200 Watts – 350 Watts)
Power tolerance: It tells how the output of the solar panel might differ from its nameplate rating under ideal conditions. For example, a 300-watt panel with 5% power tolerance means that its output power may vary from 285 watts to 315 watts under ideal conditions. Generally, a narrower power tolerance range in preferred as it represents more certainty and fewer variations in the output power.
Solar panel efficiency: This term shows the effectiveness of the panel in converting the solar energy into electricity. A high-efficiency panel can produce more electricity than another panel of similar size. The high-efficiency panels are preferred if you have limited roof space and large electricity bills. The industry average is 16%-18%
Temperature coefficient: Do you know that the heat actually degrades the performance of the solar panels?
The temperature coefficient tells how the output of the panel decreases with every degree rise in the temperature. The panels which are less sensitive to temperature are preferred by those who live in the hotter climate.
Solar panel quality: Look for brands which are ISO (International Organisation for Standardization) 9000 certified. The ISO has created a quality assurance standard for manufacturing and those companies which comply by these standards are certified as ISO 9000 series companies.
Durability: The International Electrotechnical Commission (IEC) 61215 reliability standard evaluates the durability of the panel through stress simulation of the real weather conditions. The panels which meet and pass this criterion are certified as IEC 61215. Look for this certification while finalizing the panel for your roof.
Performance and material warranties: The manufacturer’s warranty is a very important point to consider while choosing a panel for your roof. In case, the panel problem occurs post installation then a strong and long warranty will help you in getting the necessary service and support. There are two types of warranties one is Performance warranty and other is Material warranty.

Performance warranty: It is true that the performance of the panel declines with every passing year. The manufacturers claim that the performance of their panel will not degrade beyond a certain percentage every year till the life of the panel. Generally, a 0.7% decline every year is the industry average and anything less than that is preferred.
Material warranty: The material warranty covers any problems due to manufacturing defects and failures due to environmental conditions. The average material warranty is 10-12 years and anything more than this is preferred

System Designing

The one side of the system designing includes the sizing of the solar panels and all the equipment attached to it. The other aspect is physically installing the system on the roof.
The installers may offer different system sizing for the same energy requirement. Do not get confused by different sizing quotes rather inquire about the basis of the sizing. The good system designer will consider the following points:

He knows that the panel performance will decline with every passing year while your energy consumption is the same. Therefore, slightly over-sizing the system is no harm as the system output will never get deficit.
A good designer will pre-inspect the electrical appliances and may ask you to replace the outdated energy consuming appliances with the new ones. These changes will help you in meeting your energy requirement even with the reduced system size.
An intelligent system designer will keep your future energy needs in mind and if it is going to increase with time then there is no harm in getting a slightly over-sized system on the rooftop.

Also, the benefits of the right system designing must reflect on the finances. In simple words, an efficient system must have higher return on investment and faster payback period. The experienced solar installer will keep the following parameters in mind while evaluating the Return and the payback period:

Cost of the system
Maintenance cost per year
Cost of the grid electricity
The escalation in the grid electricity per year
Degradation in the performance of the solar panels with time
Solar insolation in that area
Time value of money
Total savings during the lifetime of the system

The realistic approach towards the above parameters will give the most optimum value of return on investment and the payback period.
Compare the payback period and the return of investment offered by the solar installers. A better payback period should be your choice. But do remember that it should not be unrealistic to attract customers.
The next aspect is actually installing the system on the rooftop. Keep the following points in mind:

Is your installer keeping the following points while doing the installation?
The aesthetic look of the roof after installation
The proper gap between the panels to let the air pass through them and keep them cool in summers.
Mounting panels at right orientation and right angle w.r.t. earth so that they receive maximum solar radiations
The right size of wires for connecting the panels and all the other electrical equipment
Is he using the right inverter matching your requirements?

There are mainly 2 types of inverters one is string inverter and the other is micro-inverter (The main function of the inverter is to convert the dc current into the ac current)

If you are looking for a cost-effective solution and your roof is well lit by the sunlight then string inverter is preferable.
If your roof receives uneven solar radiations then the micro-inverters are more efficient in converting dc into ac. Also, even if the output of any one panel is affected then the output of other performing panels will not be affected. However, it is difficult to maintain panels with micro-inverters.

Reputation of the Installer

You need to check the reputation of the solar installers by reading the reviews about it in the market. Keep the following points in mind while choosing an installer:

The after sales services he is offering to its client
Number of years he is in the business
The experience and technical knowledge of the team
Is he focusing solely on the solar industry?
In-house support or outsourced?

Conclusion

Comparing quotes can become easy if you know beforehand the important points for choosing the right installer. However, it is difficult to match all the parameters but if more than 70% aspects are covered then you should select that installer and go ahead with a solar installation on the rooftop to enjoy the smooth electricity for decades.

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