Solar PV Roof Slates FAQs
People who are interested in the Sunslates™ roofing system often have questions about what the system is all about. This page will hopefully answer some of these questions.
Do I need to cover my entire roof with Sunslates™?
It is not necessary to cover your entire roof with Sunslates™. You are able to install as many or as few Slates as you prefer depending on your power output requirements and design preferences, the sunslates™ will integrate well with most types of roof. In shaded areas and where PV Slates are not needed we can provide matching full and half slates for a consistent finish.
Does my roof need to face South?
The best orientation for a Sunslate™ roof is due south. However a southwest or southeast roof will have a negligible reduction in power production (2-4%) and a due east or due west roof will see from 10 to 25% less power compared with a true south facing roof. Sunslates are connected together in strings so you will find with a well designed system an east facing roof performing in the morning with your west facing roof providing power in the afternoon. Roof pitch is also a factor in power production, but it is not crucial. The difference in production between an ideally sloped roof and a regular 4/12 or 5/12 roof is usually no more than 5%.
How does the system shed water?
The Sunslates™ use an overlapping system, much like a shake roof where there are two layers at any point on the roof. Sunslates™ need at least a 4/12 (18°) roof pitch in order to shed water properly.
How are the Sunslates™ mounted on the roof?
A Sunslates™ roof starts with standard tar paper felt as used on
most traditional roofs. Sunslates™ are then mounted on the roof deck using a
series of vertical 2 X 2 boards over the rafters (usually 2' on center), and a
series of horizontal 1 X 4 boards nailed to the 2 X 2 boards at about 12"
spacing. Hooks are then nailed to the 1 X 4 boards and the slates
hang on these. This spacing off the roof creates a plenum, this allows
airflow underneath the slates, which cools the slates and helps increase
performance.
How do the sunslates™ connect together?
Each sunslate™ tile comes with a gas tight connector that wires each tile to the connecting tile. Once connected with a simple twist the tile is connected to the electricity circuit.
How are electrical connections done with Sunslates™?
Sunslates™ are usually grouped in strings of 12 or 24. Each string has a cable that runs to a junction box. On most roofs these cables go through a single roof penetration at the top center of the roof area. Cables are then routed to an inverter. Once at the inverter AC power is supplied to the properties existing electrical system and or the National Grid.
How do I sell the electricity I produce?
In most cases the company that supplies your electricity will buy what your produce this technique is called Net Metering. Based on the amount you export/Import you will either be invoiced for the net amount you import or paid for the net amount you export. A common situation with Sunslate™ installations in the UK is to be a net exporter in the summer months and a net importer in winter.