Solar panels on the wall or on the roof?

Using wall surfaces for solar production has become more and more common in recent years. A good example of that is you, reading this article right now. In this text, I try to explain what has made wall-mounted solar systems more popular and also tell why our RAULI WALL is an excellent choice for such installations.

To begin with, it is good to note that most solar panels are still installed on roofs (or actually on the ground in huge solar parks, but we leave those out of this article). However, during the past few years, wall-mounted systems have clearly grown in popularity. There are many reasons for this, but there are also some clear advantages that wall installation offers compared to rooftop systems.

Advantage of wall installation

1. Wall surfaces offer plenty of free space.

In square meters, the roof usually provides more area, but many roofs have technical rooms, air conditioning pipes, or other obstacles that limit where panels can be placed. Wall surfaces, on the other hand, are often empty. When you think about it, a clean wall without panels is not used for anything productive.

Many property owners have realized this and want to make every available square meter produce energy.

2. Roof load capacity.

In the Nordic countries and other snowy regions of Europe, heavy snow loads create challenges for flat roof installations. Buildings in snowy areas are designed to carry large snow loads (sometimes over 5kN/m²), but when solar panels and their heavy concrete ballast are added, the roof structure can easily reach its limit. In such cases, installing panels on the roof may simply be too risky. Very few people want to take this risk. Installing the panels on the wall becomes a logical and safe option.

3. South-facing walls produce excellent electricity.

One of the first questions property owners ask is how much electricity wall-mounted panels can produce. It is true that panels placed at a 90-degree angle do not produce as much energy as those installed at the optimal tilt, but in real-world installations, conditions are rarely perfect. Most flat-roof systems are built with an east-west layout to maximize roof usage.

When comparing a south wall system to an east-west flat roof system, productions in the Nordic region are quite similar. If we include the “zero-production” winter months caused by snow on the roof, wall systems can even perform better. In Central Europe, where snow is rare, east-west installations may produce about 10–15% more electricity.

4. Electricity production during the heating season.

In the Nordic countries, the sun is low during early and late parts of the year. This is a challenge for rooftop panels, especially when snow covers them. Wall-mounted panels do not have this issue and continue to produce electricity even when the sun is low.

5. Benefits in hot climates as well.

Snow is not everywhere. In fact, most of the countries have the opposite problem: too much heat. Wall-mounted panels provide extra insulation, shading the south-facing wall and reducing the need for cooling inside the building. This will lower energy costs and improve the return on investment of the solar system.

6. Impressive appearance.

Last but not least, wall-mounted panels simply look great. Almost every project we have worked on has shown the same thing again and again. A wall covered with solar panels is visually impressive and gives the building a modern, high-tech look. In many cases, covering the wall with panels is also the most cost-effective way to improve the building’s appearance and increase its value.

In addition, a wall-mounted solar system is excellent marketing for the companies operating in the building. Everyone passing by can clearly see that solar energy is being used. With rooftop systems, this must be shown to visitors through roll-up banners or information screens inside the building.

RAULI WALL

Now that we have looked at the reasons behind the growing popularity of wall systems, I will briefly introduce our RAULI WALL solution. RAULI WALL has quickly become a favorite among both installers and end users, and I believe I know why.

I start with the simplest and most obvious thing again. RAULI WALL is a system designed exclusively for wall installations. I want to highlight this because even today, some solar panels are still installed on walls using roof mounting brackets. The most common example is screwing roof brackets into the wall and building aluminum rails the same way as for pitched roofs. If you know someone who has done this, ask them how easy it was to install. I am quite sure it was not. And I would also argue that such roof brackets have never been tested for wall installation durability.

RAULI WALL consists of two main parts, top and bottom elements, between these the solar panel “floats” freely. Installing the panels is fast and can easily be done from a lift, which is how wall installations are typically done. The elements have fixing points every 30mm, allowing safe installation on all types of wall surfaces. I have never met an installer who, after using RAULI WALL once, would want to install any other wall system again.

RAULI WALL is fully tested, which has been a key requirement in several large-scale projects where our system was selected. The products are made in Orimattila, Finland, from Nordic high-strength steel, and production follows ISO 9001 and ISO 14001 quality and environmental standards. The system also holds a local EMI certificate in Hungary.

Our most important customer is, of course, the property owner whose building the RAULI WALL components are attached to. Year after year, the feedback from end users has been the same: RAULI is an exceptionally stylish system, and its Nordic quality gives peace of mind.

You can design your own wall installation using our RAULI APP design tool. The app calculates all required components, the system’s annual energy production, and its CO₂ emissions. It also tells you the cost of components in real time. If needed, you can also download our BIM libraries for Revit or AutoCAD and design the system there.

Thank you very much for reading this far.
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Sunny regards,

Ville Tiainen
CEO
+358 44 979 5042
ville.tiainen@raulibrackets.com

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