How To Get Solar Panels On A Heritage Home

Old houses are a blessing, but energy efficiency isn’t always a strong point.

Can you install solar onto a house and still preserve its historic character? It is possible, but you may need to appease the neighbours and some narrowly designed rules. Read on for some good points to raise in support of your planning application.

Do Heritage Rules Apply To Solar?

If your neighbourhood has a heritage overlay and you want solar, there’s likely a council application to be made.

The terminology will vary. It is a contributory building? a local heritage place? A state heritage listing? There are many classifications but the key question is how significant the authorities and local community deem your house is.

Government House in Adelaide was thoughtfully designed to put the service section of the governors residence on the north side. Even the chimneys are ideally placed out of the way for solar.

What Can Be Seen From The Street?

My former GP curses about “the trust” sometimes.  It’s not the Housing Trust (public housing authority) but the National Trust. These people give you a brass plaque and, like it or not, dictate you can’t paint football colours on a grand old house.

I haven’t had to deal with an officious planning department or heritage officer who likes to throw their weight around, however I’m glad they get an opportunity to preserve a sense of place.

That said, there’s a place for pragmatism and if you can work “adaptive reuse” into your application it will bode well.

I have seen a new shed with a corrugated zinc roof,  built with pitch, dormer window and detailing to complement the adjacent timber cottage with its own zinc roof (not galvanised). Council mandated the zinc shed roof must be painted, to match the zinc house roof.

Speaking to a number of local planning departments, the consensus seems to be that if you can’t see it when you’re standing on the street, then you’re free to fit what you like.

If you will be able to see the solar from the street, then there might be some papework ahead. There’s helpful resources for most states and territories to guide you, although these won’t necessarily cover your local council rules:

• Victoria
• NSW
• Western Australia
• Queensland
• South Australia
• ACT
• Tasmania

Heritage rules have their place. At the back of a grand 2 storey pub, this stable languished for at least 16 years, but it’s proof that even humble functional buildings need protection – all it needs now is solar.

Integrated Approaches

Solar roof tiles have been the next big thing for a few years now, but as far as I can tell, they’re just a bit too expensive to be a mainstream product, because Australians are cheap.

Heritage tile roofing might be a compelling place for it, provided the heritage experts aren’t stuck on the roof material itself being the intrinsic value they’re preserving.

Solar tiles are otherwise known as BIPV or building integrated photovoltaics.

Slate tile roofs are difficult to work with, it’s best done with a slater working hand in glove with the solar team on install day. For solar tiles you may still need a slate roof expert to integrate flashing around the edges, but they shouldn’t be falling over each other.

The English solution to solar shown below is one I’ve seldom seen, but it’s a lovely look for what are cheap, conventional solar panels.

In the UK they often build with waterproof membranes, which have battens over the top, and tiles or cladding to keep the weather off.

An Australian Take

A local approach may vary according to local regulation. Finding a builder interested could be the biggest challenge, however as a qualified roofer this is how I’d do it on my house:

• Strip the existing roof iron (or tiles).
• Install noggings between the rafters, in parallel with the roof purlins, on centres determined by the solar framing system to be used.
• Remove the old roof purlins & sheet the top of the rafters with 10mm plywood bracing.
• Thickness or structural spec of the ply would need to be determined, along with any use of sarking or membrane for condensation control.
• Have your roofer install a new flat sheetmetal cladding with raised edges to meet the original roof plane – in roofing parlance, a huge pan flashing, or a shallow box gutter for want of a better description. This is the waterproof membrane that must drain into the gutter and keep the vermin out.
• Install the solar framing and panels. Framing rails need to be quite shallow, perhaps only 30mm tall, vertically fixed straight to the cladding with neoprene isolators.
• To finish the roofers return with custom flashings to cover the edges of the array, fitted tight to new iron or tile cladding on conventional battens/purlins, to prevent leaves & birds getting underneath.

Heritage value hiding in plain sight. We didn’t realise we were fixing solar to a timber shingle roof until we had difficulty making a hole for a conduit. Sadly much of this building has suffered unsympathetic work.

Adelaide City Council have been quite proactive with grants for residents and their own solar on the town hall, however the array is invisible from street level.

I Wish It Was More Trendy

I mean lots of old houses are given stark white paint jobs with fashionably grey roofing. If solar was seen as a statement instead of a an economic grudge buy, we’d have more solar and less junk left out for hard rubbish.

It’s not greenwashing or chasing rebates that motivates solar customers to electrify. Eliminating gas is a no brainer, electric heating and cooling make great sense, and moving to an EV is probably the best bang for buck anywhere.

All of this work needs sunshine to power it.

In a recent application I saw, the proponents already had:

• 5.59 kW of east-facing panels,
• backed by a 13.5kWh of Tesla Powerwall 2 storage,
• making the house around 74% self-sufficient in summer.

That’s good, but it’s not enough. Once the hot water and cooking go electric, demand goes up. And in winter or on cloudy days, their solar can’t keep up. So more west-facing solar was being sought with heritage approval to make it happen.

Practical Need Should Override Aesthetic Arguments

Yes, the application explained panels will be visible from the street. But so are the power lines, the aerials, gas meters and in summer, the air con units dripping into driveways.

In this instance the application pointed out Melbourne has already warmed by up to 1.4°C since 1950. Two multi-day heatwaves in 2009 and 2014 killed hundreds of people.

The street’s original design, with shady setbacks, big blocks and a backyard outhouse was all meant to protect amenity and health in the days before antibiotics and air conditioning. However the environment it was designed for doesn’t exist anymore.

If we want to preserve the purpose of the heritage area—liveable, healthy homes with gardens and social space—we have to let those homes adapt.

Slapping solar panels on a heritage-listed home might sound like an architectural crime to some, but what’s really more offensive: clean energy on a roof, or letting climate change slowly cook the street your kids ride their bikes down?

History Isn’t About Freezing Time

While planners talk about the value of consistent setbacks, materials, and streetscape character, we mustn’t forget it’s also about creating and maintaining a pleasant environment. If heatwaves kill the trees, dry up the gardens and force residents to retreat indoors with the blinds drawn, what heritage are we preserving?

Solar helps prevent that, powering the air con and the e-bike you can realistically replace a car with in a well serviced neighbourhood.

Solar keeps things running when the grid falls over under the strain of the urban heat island effect. It’s well documented that by cutting demand on the grid, reliability has consistently gone up. Every kilowatt-hour generated on-site is one less that needs to be dragged through a transformer and released as waste heat in your street.

Strict Heritage Rules Risk Missing The Point

We’ve now got planning clauses that talk about climate, natural disasters, and the need to adapt. Even the building standard AS1170.2 has a climate multiplier baked into the engineering calculations we use for wind loading on solar arrays.

If your local authorities say your solar can’t be approved just because it’s good for the environment, those same panels do help maintain the amenity the heritage rules were written to protect.

In short: they keep occupants comfortable in the houses everyone loves to see from the outside.

Heritage overlays are seen as more important than the design code that calls for better environmental standards. We probably need to upend that.

For more on what to consider when getting solar panels, read our detailed guide.