Solar power shopping
Solar energy is taking the world by storm.

The number of solar installations worldwide has increased by 50% just in one year. Countries leading the solar revolution are China and the U.S1. Only in the U.S., solar generates electricity to 8.7 million homes. And according to Solar Energy Industries Association, increasing number of solar systems can be attributed mainly to the reduction of 63% in the price during the last 5 years2. However, lower price should not be the only criterion to consider when looking for the best option to power your house.

In fact, thorough research prior buying solar panels is necessary for your satisfaction and return of the investment. You should start from seemingly the most trivial questions, such as “How many sunny days my area gets?” They will prepare you to answer more technical parameters the solar system should have to be the most suitable for your requirements.

Your research starts here…

When on the quest after the best solar installation, the amount of information available on internet can be overwhelming, especially if you do not have any previous experience with solar.

Here are some important questions to start with:

  1. How much sun does your house get based on your location?
  2. How much space do you have for solar panels and what material is the most suitable for you?
  3. Where would you like to mount the system and how?
  4. How much electricity does your household use?
  5. Do you use energy efficiently?
  6. What is the potential of your house for saving energy when switching to solar?

This set of questions should help you narrow down the search and get a clearer idea about the right solar system for your house.

Continue reading to learn more in detail why they matter.

Tips to help you find answers

1. Sun becomes the center of your domestic universe
Energy generated by the solar system depends on the number of peak sunlight hours your location gets throughout the year. You can find useful solar maps with data you need online. Detailed information for the U.S. is on the website of the National Renewable Energy Laboratory. And for Europe exist precise GIS maps on the website of the European Union.

The general rule (in the northern hemisphere) is to install solar panels on the southern part of the roof to ensure the highest efficiency. But that does not mean you cannot harvest enough energy even from western or eastern position. You just have to take into account reduced amount of direct sunlight on the panels throughout the day, which will reflect in how much energy the installation can approximately generate per year.

2. Position is the key to success
How fast will solar investment pay back depends on how you position the system. Your goal is to achieve unobstructed sun access throughout most of the day. Advanced systems even come with sensors that follow the sun as it makes its way on the sky during the day.

Nevertheless, most of us think of getting a static roof systems, but even these come with a set of prerequisites to take into account:

    • Is your roof in a good structural shape and has roofing that will last for minimum 25 years?
      Make sure you have your roof assessed prior installation. It would cost you more, if you had to change roofing couple years after putting solar panels on.

    • Are there trees around your house that might shade the roof when growing larger?
      Scan around your property for young trees that might grow large enough to decrease efficiency of your solar system. Keep this in mind even when planting new trees.

    • Is your area exposed to extreme weather events?
      In the area with strong wind or hurricanes, make sure your mounting system is tested and approved for local weather specifically.

    • How much snow does your area get?
      If you live in an area with long winter and heavy snowfall, it might be more suitable to get a system on a stand, where you can position the panel according to the conditions. In the summer, you can tilt your panel horizontally, while in the winter vertically for snow to not cover it. Vertical angle will also accumulate sunshine reflected from the snow on the ground.

3. Material affects energy output
The largest proportion of solar panels is made of crystalline silicon, which is sold either in the form of monocrystalline panels or polycrystalline panels. Both options offer some advantages. You should choose one according to your space availability and finance.

Monocrystalline panels are more expensive choice, but they come with higher efficiency compared to polycrystalline panels. Higher efficiency reflects in the space needed for their installation. If you have a limited space, you might want to reach for monocrystalline panels. However, their downside is reduced performance when shaded or dirty – something that affects polycrystalline systems less3.

Thin film solar cells are becoming increasingly popular because they reduce the amount of material needed for their creation, which lowers costs of their manufacture. Amongst their advantages is flexibility and minimal effect of shading on efficiency. Although, overall efficiency and product life expectancy is lower than at crystalline panels. They are also space demanding as it takes more cells to provide sufficient amount of energy3.

4. Energy to cover your needs

Now we are getting to the core of the problem – how much energy do you actually need?

Have a look at your power bills over the course of a year and calculate your daily use of energy. Pay attention to seasonal fluctuations. In summer and winter months you have to count with higher energy input to maintain comfortable temperature inside your house. Perhaps the best strategy is to calculate the daily average for each month to have the most precise idea.

Based on your actual energy needs, you can narrow down your focus on the solar system you need. The average size in the U.S. is 5 kilowatts. Such system costs on average (in 2017) between $10,000 to $13,500 after tax credits (30% of the total cost). If you need more energy, you can choose systems of 6, 8 or even 10 kilowatts, costing up to $22,0004.

The final price might differ depending on the provider you select. Keep in mind, though, that it is better to contact more providers in your area and get their bid for your house, as well as information about the quality of their product with the length of warranty they offer. When it comes to such an important element as long-term energy generation, you should avoid taking the cheapest product, as it often reflects the quality of the material. Preferably, pick the provider from the average price range.

5. Saving starts with efficiency
Before you buy the solar system, make sure you use energy efficiently. Properly sealed and isolated houses save significant amount of energy, which is otherwise disappearing into the thin air and pulling money from your back pocket without you noticing. By preventing unnecessary losses of energy, you may even need a smaller sized solar installation, and therefore, pay less for the system.

Not sure where to start? Check Greentumble’s list of tips on how to improve energy efficiency at home.

6. Solar boosts your wallet
Solar systems do save money. How much depends on many different factors, so it is not easy to provide a concrete number without knowing the cost of electricity in your area, your actual energy use or the number of peak sunlight hours your house gets.

However, based on the previous clues mentioned in this article, you should be able to get fairly close estimate, how much you will save with solar panels. Simply look at how much do you spend on electricity in a year. Then, multiply this number by 25 years (usual warranty time by majority of providers) and compare it to the price of getting solar panels.

Other option is to use solar calculators. They will help you to get more precise information about the expected performance of solar projects in your area. Here are some suggestions.

After you have considered these basic questions, you will have a clearer idea where to start when shopping for solar panels. Join the movement of eco-conscious consumers and embrace this increasingly available opportunity to utilize freely accessible source of energy.




Written by Greentumble Editorial Team