Sunny and shadow side of the solar roof


Fancy turning your house into a power factory? Surely, solar panels are an option, but how about a two-in-one green energy producing roof cover? Debuting in Colorado in 2011, solar roof tiles have been conquering households and commercial buildings alike. The same as photovoltaic panels, solar tiles harness sun’s energy to generate power. Additionally, they replace (partly or fully) the original shingles of the roof. Miniature, good looking squares instead of grand mounting systems sound quite appealing. Therefore, we summed up the main pros and cons of this solution that literally ‘’goes through the roof’’:

+future investment: whether connected to grid or on island (off-grid) mode, you save on electricity costs by using renewable, abundant sources of energy and reducing CO2 footprint simultaneously.

+tax credits: in some countries, you can even get tax rebates from the state by installing solar power.

+roof replacement: lightweight and durable option if you are planning a roof renovation (either replace the entire roof or integrate a few shingles into existing one). In that case, it is 10% to 15% more cost effective per watt of solar energy than a new roof+new solar panel system atop.

+aesthetically pleasing: tiles collude with your roof and are available in various colours, a particularly important aspect for solar integration into historical buildings as well as modern architecture.

The four roofing types presented at Tesla’s solar roof launch (left to right): Tuscan Glass Tile, Slate Glass Tile, Textured Glass Tile, Smooth Glass Tile (photo credit: Tesla)

+warranty: they are expected to last 20-25 years (depending on model)  and maintain more than 80% of power output after 20 years. Tesla claims to offer ‘’infinite warranty’’ for their tiles, but time has to pass to prove it.

+increased value: houses with solar roofing will stand out in the market.

specific requirements: since the tiles can’t be re-oriented after installation, they are affected by the angle, design, size and material of the existing roof structure, as well as shading from surroundings. Your roof pitch has to be at least 14 degrees and highly exposed to sunlight.

slow installation process: conventional solar panels can be installed in a day by an engineer, while a solar roof takes up to two weeks and 10x more manpower 

(Tesla roof showcase in California: 

lack of experience: compared to extensively used panels, less companies are familiar with the installation process of the solar tiles. It might be challenging to find a well trained local installer and if you do- it won’t be cheap.

costs: solar tiles are at least twice as expensive as panels. 

The average solar panel installation for a 3kW system costs 3,500- 5,000. Replace solar panels with solar tiles and you are facing a cost of 9,000- 10,000 instead.

lower efficiency: as they don’t have a ventilation gap underneath, tiles are more exposed to overheating that lowers their output. Due to 10-30 more connection points (compared to a panel system), solar tiled roofs are likely to have more electrical faults over years. 

Resume: Solar tiles are worth the investment if a) aesthetics are a crucial factor, b) roof replacement is needed and the available surface area for installation is enough to cover your energy needs, c) you are a greentech fan and want to, as Elon Musk puts it,  ‘’make your roof more alive’’ 🙂 

Otherwise, solar panels still are the winning choice- shorter return on investment, higher efficiency, lower system costs per kWp, easier installation process and more scalable project. Not to mention the ease of maintenance and experts available to do the job- solar tiles still are a bit like flying to the Moon for most of the installers. It could change soon though- you will see how decreasing PV costs and growing interest in BIPV (building integrated photovoltaics) affect the future of sunny roofs. 

About the author: Anna Indricane

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