What are solar windows?
Solar windows are a changing technology, and the term can mean any number of things. In the context in which we're talking about them here though, they're windows used to generate electricity from solar energy. Solar windows are technically referred to as 'building-integrated photovoltaics' - photovoltaic panels that take the place of a conventional material or aspect of the building envelope.
The most common type of solar window is a double glazed sheet of glass, specially treated with dyes that absorb and re-emit light outside the visible spectrum. Much of this light is reflected internally between the panels to solar collectors at the top and bottom of each window, while still letting in enough light to fulfil the window’s main function.
A great deal of research is going into producing transparent solar panels for use as windows. This can include film treatments which are sprayed onto the glass, and the placement of micro cells which are barely visible to the naked eye. New developments in solar technology are being discovered all the time, and the future of solar windows and BIPVs in general looks more or less certain, particularly in the commercial sector where high rise buildings can offset a large portion of their running costs by putting all the sun exposure the building will get to good use. For the time being, though, they're a bit of a niche option for homes.
When are solar windows appropriate?
Solar windows can be used almost anywhere, but are likely to be especially useful if you want to generate solar power in an apartment with no roof or ground access. They can also be installed as skylights - and are particularly well suited to this use because of the exposure they're likely to get on a roof. Though these arrays are not as effective at generating electricity as dedicated systems, they can contribute enough to make them a worthwhile investment over time.
The biggest growth area for solar windows is in large scale commercial construction. Skyscrapers in a city can act as giant solar batteries, storing megawatts of power through the sun exposure on the glass. This can save thousands on lighting and heating bills as well as contribute to reducing the building’s environmental impact.
What issues surround solar windows?
Solar windows aren’t any heavier than standard windows, but will require special installation to wire up to the mains power. They are also as vulnerable to damage as a normal window, but will be vastly more costly to replace should they get broken. You may have to visit a specialist company to get replacement glass, and if that company goes out of business, you might find yourself unable to replace a broken window.