Solar power used to be reserved for satellites hurtling through space or remote off-grid research stations.
That has all changed in recent years due to generous governments subsidies, maturing renewable energy technology, and a massive fall in the production costs of solar technology.
Solar power can be classified as an investment. Not only does it increase the value of your home, but it also locks in your electricity prices.
A kWh produced by your rooftop solar system today will cost you the same ten years from now as it’s not subject to inflation, unlike your local energy utility kWh charge.
The other major advantage of solar power is that it’s clean energy, producing free clean power. Solar power will assist you in becoming more energy independent and reduce your carbon emissions.
It’s becoming more commonplace to see rooftop solar PV systems across residential neighbourhoods. Plus it’s generating a lot of interest within the public.
But there are certain misconceptions about solar power and, as such, many homeowners have questions about rooftop solar PV, such as whether it would be ideal for their home.
Here we dive into some of those questions and help gain a better understanding of whether rooftop solar PV is ideal for your home.
A solar panel harnesses energy from the sun and turns this energy into electrical power by a chemical process within the solar panel.
Solar panels need direct sunlight to produce the largest amount of electricity.
Even on cloudy days, solar panels still generate electrical power, but at a much-reduced rate than what can be expected during peak sun hours—usually between 25% and 40% less than during peak sun hours.
What exactly are peak sun hours though?
Peak sun hours refers to how much solar energy is available in a certain area during a typical day. A peak sun hour is an hour during the day in which the intensity of sunlight is 1,000 watts per square meter.
The amount of solar radiation delivered to your solar panels varies from day to day. It depends on such variable factors such as the sun’s position in the sky, clouds, seasons and other atmospheric conditions, as well as other fixed conditions such as the location of the solar system in relation to the equator and whether there is shading on the panels or not.
In general though, if your solar system receives seven hours of sunlight per day, then you should have something like three to four peak sun hours per day.
Is My Roof Suitable for Solar Panels?
Solar panels need to be properly secured as a permanent installation and must also be able to handle harsh environmental conditions such as high winds.
That means there are some things to consider before taking the exciting plunge into being more self-sufficient and doing your part to reduce carbon emissions.
Is my roof suitable for solar panels? If so, where do I put my solar panels?
There are a few things to consider here, such as:
- How much roof space do you have available?
- What type of roof is it?
- What direction is it facing?
What is the Best Position for Solar Panels?
If you live in the Southern Hemisphere, then the optimal direction for your panels is to install them facing North.
If you live in the Northern Hemisphere, then the optimal direction for your solar panels is facing South.
Having them installed in these directions maximises your electricity production during the day.
Solar panels can be installed on East and West facing roofs and in some cases this is ideal, especially for residential homes. Installing your solar panels in this configuration maximises your solar output during the mornings and late afternoons.
Most homes consume the most electricity during the early mornings and late afternoons.
The more roof space you have facing either North, East or West the better, as it means there is more space to install solar panels and increase your solar output.
Solar Panel Tilt Angle
Having the correct tilt angle for the installed solar panel’s is also an important consideration.
This is necessary for your panels to be able to catch the most sun during the whole course of the day. The best solar panel angle for your home depends not only on where you live but also what time of year you will be using your solar panels the most.
For panels that you will want to use all year and not have to touch once they are installed, you will want to make sure your solar panels are installed at an optimal angle.
There are many websites that provide the required formulas for calculating this for you.
Type of Roof
Your type of roof is another important part of the equation when it comes to installing solar on your home, although with technological advances, it’s less significant today than a few years ago. As the technology has matured, so have the types of roof mounting systems and, as a result, many different roof types can be adapted for solar power.
The roof mounting systems are designed to ensure the solar panels are secure enough to withstand high winds and other environmental conditions for the lifespan of the panels.
Metal roofs are the best types of roofs for installing solar panels, as metal roofs are lighter than tiled or concrete roofs and can support more weight.
The most important thing is that your roof must be able to carry the extra load of the panels.
There are roof mounting systems for all different types of roofs, but it’s worth confirming first if your roof can take the extra load of PV panels. On average roof-mounted solar panel installations weigh 10 - 20 kg per square meter, including the mounting system. This is within the weight limit of most modern roofing systems.
If your roof is old and requires replacing, then it makes more sense to replace the roof before installing a solar PV system that will be on your roof for the next 20 to 30 years!
The Effect of Shading on Solar Panels
Shading is a real negative for PV panels. If a solar panel or multiple solar panels are covered by shade during the day, then this severely reduces the amount of electrical solar power produced.
Shading can come from nearby obstructions such as walls, trees or even other buildings. During the period the PV panel or panels are covered by shade, electricity generation will be reduced.
Therefore it’s advisable to do a roof assessment to identify shaded areas during the course of the day and avoid installing PV panels in that specific area.
The Solar Panel Installation Process
As with any new project, planning and design are of the utmost importance. Before embarking on the installation of a rooftop PV system you need to determine the size of the PV system required.
This can be determined by looking at past utility bills and calculating your annual energy consumption.
There are a lot of Solar PV software design tools out on the market that assist in sizing the PV system according to your annual energy consumption. Some of them are freeware and others are shareware.
Once the PV system has been sized correctly, the amount of rooftop space and the location of the roof needs to be determined.
The installer must also identify a suitable place to install the PV inverters. PV inverters convert the DC power from the PV panels to AC power.
After all, this has been done, the installer can start installing the mounting system on the roof and the grounding cable.
Then the process of installing the panels can begin. The inverter must be mounted and installed close to the main AC supply point of the house too.
All other electrical equipment, including junction boxes and conduit for the wiring, must be installed at this time.
Only then should all the wiring be done from the PV Panels to the inverter and then from there to the main AC supply.
All wiring and equipment should be double-checked to ensure there are no loose connections and that cabling is connected properly.
Electricity can be very dangerous, thus it’s recommended to only use qualified installers that adhere to local safety, solar PV installation and grid connection guidelines.
Before going solar, check if your roof is suitable for solar.
First, check sun timing and position, then your type of roof. Don't forget about shading.
It's always better to work with local installers who know the specifics of your area and choose one who lets you request an inspection before you sign up.
Only go with trusted and experienced installer!
After the successful installation of your Solar PV system, there’s nothing more gratifying than watching the solar power generation meter on your PV inverter tick over in kWh’s of clean, free energy being produced!
If you want to see how much solar or battery storage could save you over the next 5 years, then take our solar saving calculator quiz below!
Or talk to an Instyle Solar expert about the best solutions for home energy storage or PV-panels.
Otherwise, head back to the solar blog to find even more great educational content.