Everything You Wanted to Know About Solar Panels But Were Afraid to Ask.

Last modified on September 3, 2020

Solar panels, also known as photovoltaic (PV) panels, form the cornerstone of any solar energy system because they convert sunlight into electricity. Here are some answers to the most common questions we get about solar panels.

What is a solar panel?

A solar panel is an energy conversion device. It’s composed of silicon photovoltaic cells sandwiched between two layers of EVA film (encapsulant), a layer of protective glass and a backing sheet.  There is also a junction box to house the wiring and a metal frame to hold it all together.

How do solar panels turn sunlight into electricity that I can use?

  1. When sunlight strikes the solar cells, electrons are knocked free of their molecular bonds in the silicon material. 
  2. When connected to an electrical circuit, these loose electrons are set into motion and this creates direct current (DC) electricity. 
  3. The current from each panel is collected by a system of wires and fed into an inverter that converts the DC electricity into the alternating current (AC) electricity that powers your home.
  4. This electricity is now ready to be used in the household, stored in a backup energy system, or fed into the grid for credits to be used against later household consumption.

How big is a solar panel?

There are two common form factors for most residential and commercial applications: 170 cm by 100 cm and 200 cm by 100 cm.  Panels are generally between 35 and 50 mm thick and most panels weigh between 18 and 20 kg.

How long do panels last?

Because solar panels use simple technology and have no moving parts they last a long time. The first 25 years after installation is typically considered the panel’s “useful life” but it can continue producing electricity for many years after that.

What kind of warranty coverage do panels have?

A new solar panel usually has two warranties:

  1. A panel’s product warranty warrants that the panel will remain structurally intact and free from physical defects for the warranty period (ranging from 10 years to 25 years).  Each warranty will have its own standard exclusions and requirements that must be met before a claim can be made so make sure to read the warranty.
  2. A solar panel’s performance warranty will typically warrant a certain level of production at the 10 and 25 year milestones. The panels may produce a greater amount but this is the minimum warranty production at 10 and 25 years.
Sample performance warranty – linear over 25 years

What brand of panels is best for my system?

When choosing the best panel for your system, you should consider a panel’s performance, quality, durability, warranties, and availability in your region. With thousands of panels available, this can be a daunting task. If you are working with a professional solar installer, they will recommend the panels that best suit your needs during the design phase.

Do solar panels work in the shade (partial shade)? 

The most significant negative impact on solar energy production is shade. Even if only a minimal amount of your solar array is shaded, the effect on the performance of your entire system can be considerable. For this reason, it is very important that your solar energy system remains out of shade throughout the day wherever possible.  We recommend shade free operation from 9am to 3pm (10 to 4 daylight savings time).

Will I need to wash my panels?

In most cases, a combination of precipitation, wind and the array slope keep the panels free of whatever dust, pollen and bird droppings may accumulate. Only rarely does the soiling reach a point where production is significantly affected. If it becomes necessary to clean your panels, a soft scrub brush with warm soap and water should be sufficient. Avoid harsh cleaners and abrasive scrubbers as these can damage the glass panel and affect production. Pressure washers can actually damage panels by driving high pressure water into the seal between glass and frame. Rooftop panels can also be very difficult to access; hiring a solar service provider to clean the panels for you may be the safest option.

Will I need to clear the snow from my panels in the winter? 

Solar panels are usually installed with enough of a slope (and southern exposure) that sunlight and gravity will clear the snow from the panels in a day or two. A little lost production from a grid-tied array is definitely better than the risks of climbing onto an icy rooftop, being struck by a heavy piece of falling snow, or damaging your solar equipment. An exception is an off-grid system where a day or two of lost production is not practical. When waiting is not an option, a roof rake with a rubber head (and a gentle touch) can remove the snow from your panels. The aforementioned risks still apply so please exercise caution when clearing your panels. Ground mounted solar panels are much more accessible for snow clearing and cleaning, should it be necessary.

Are they any options for panel colours?

Most solar panels have black or blue solar cells, silver frames, and white backsheets.  Black frames and/or black backsheets are also available.  Clear backsheets are used in bi-facial solar modules.  Modules with exotic colours, either in the frames or the cells themselves, do exist but are not generally available. 

What is a bifacial module?

Traditional (ie. monofacial) solar panels use the top (front) face for solar energy production.  Bifacial panels use both the top (front) and bottom (back). The bottom of the panel absorbs the light reflected off the surface below it. Naturally, different surfaces reflect varying amounts of light: by comparison, grass reflects 20% of sunlight while a white surface reflects more than 80%.  Bifacial panels can be used to increase generation in certain applications and site conditions and are ideally suited to ground mounted off grid applications.  The reflected diffuse light from snow below a ground mounted solar array can increase winter generation by 30% or more.  Be aware that bifacial modules require bifacial-specific racking.

What about all of the new solar technology I have seen on the web? 

From spray-on solar cells to flexible solar panels and solar shingles, there are many emerging solar technologies. While some of these products are ideal for niche applications (eg. the flexible panels are great for mounting solar on a vehicle or trailer roof where flat surfaces are not always available), traditional panels remain the best choice for most residential PV systems because of their lower cost and greater efficiency.