PHOTOVOLTAIC PANELS
Roofs on Aussie houses are becoming increasingly cluttered. This bulletin focuses on photovoltaic panels. (PV panels for short.) The different types of PV panels are described here – standard, recessed, and integrated. Issues with panels are then discussed, along with potential design standards.
Standard PV panels
The standard panel is the common rectangular panel mounted above a roof. Each panel is square, approximately 1 m x 1 m. The panels themselves are black. The glass can be highly reflective. The edges of the panels (‘frames’) have conventionally been silver coloured, but panels are now available with black frames. Mounting leaves a gap between the back of the panel and the underlying roof cladding, and so the panel typically casts a shadow on the roof. A typical rooftop array has at least six panels. Sometimes an inverter box is also visible next to the panels.
Standard photovoltaic panels mounted above an existing roof. These can be an eyesore.
Recessed panels
PV panels can be recessed to be flush with the roof plane. This makes them less conspicuous. This technique is more suitable for new construction than for retrofitting.
Recessed/ Inline solar panels are flush with the roof plane, and so are less conspicuous than standard panels.
Integrated PV
Some roof tiles, windows and wall and roof cladding can also generate electricity. PV roof tiles can replace a whole roof or just part of it. PV tiles are more expensive than standard PV panels but look much nicer.
Solar tiles are roof cladding that also generates electricity.
Siting
Photovoltaic panels are now so efficient that they work on a roof plane facing any direction. For maximum electricity generation, PV panels should face as close to true north as possible. However, if a house’s occupants are more likely to have higher power demands during the afternoon and evening, a west-facing position may be preferable.
Photovoltaic panels are now available with black edges, reducing the visual clutter.
Issues and potential controls
PV panels can look unsightly and can add to the number of disparate elements on a roof, making it cluttered. Inverters also add to the clutter.
“As standard solar panels are considered unsightly, they may be installed on roof faces that do not directly face the streetscape.” (Heritage Estate, Chirnside Park, Victoria)
If a house’s north or west facing roof planes are also facing the street, the optimum panel locations may be a poor choice for the streetscape. To minimise their prominence, solar panels may be placed on the rear part of the roof or be low profile. Minimising the colour and tone difference also helps to minimise prominence.
“PV panels and solar water heating system panels may be installed flush on the roof except on the face closest to the street.” (Atticus, Woodstock, Victoria)
For resource efficiency reasons, some estates require their installation.
“A minimum 5kW solar photovoltaic system must be installed on every house with two bedrooms or less.” (Clarkefield, Macedon Ranges, Victoria)
An estate’s design code and design review panel might take into consideration various factors when considering the placing of panels on a roof such as:
- Prominence from the public realm;
- The size, height, shape, reflectivity; and
- The colour of the system and the surrounding roof cladding.
The shape of the PV panels can be an unsightly contrast to the shape of the roof panel they are placed on. A darker roof can minimise this contrast.
While PV panels may be seen as an eyesore, they are becoming ubiquitous on new Australian houses. They may become like cars parked along a street – barely noticed. In the meantime, an estate developer must decide how restrictive to be regarding their placement on roofs. An estate’s design code might allow panels anywhere on a roof, restricted to less conspicuous areas, require only solar tiles or recessed panels, or ban them altogether.
