Huw Watson moved into his "bright and sunny" studio apartment in Newtown in August last year.
"It had this sort of big, open, airy feeling. And you could open up the glass sliding doors, and it was really lovely there," Mr Watson said.
A couple of months after moving in he returned from a work trip to find the front of the building covered in black scaffolding.
His street-facing floor-to-ceiling window and balcony were now enclosed by the material, blocking most light.
"It made it almost like a dungeon and very claustrophobic," he said.
After a few months, Mr Watson moved out and his case ended up in the NSW Civil and Administrative Tribunal.
It is a problem not just limited to tenants as the need for greater urban density increases the potential for existing residents to lose access to sunlight.
So what rights do residents have to natural light and why do we need it?
What does the law say?
Residential tenancy laws were updated in late 2020 to clarify what "fit for habitation" means.
The minimum standards specify a property must have adequate lighting in each room, except garage or storage spaces, but it also says that can be natural or artificial lighting.
However, if things change after the tenant signs the lease, it can be deemed a loss of amenity.
Tenants' Union of NSW policy and advocacy manager Jemima Mowbray said residents may be entitled to a rent reduction.
"They've agreed to that price based on a range of features and amenities. It may not be the landlord's fault but it is a reduction in amenity," Ms Mowbray said.
However, she said many were unlikely to pursue it in the current tight rental market, fearing no-cause eviction or a rent increase.
Mr Watson did request a 50 per cent reduction in his weekly rent, from $430 to $215, or to be released from the lease.
He said his landlord and real estate agent rejected that request and did not suggest a counter-offer.
Why do we need natural light at home?
Mr Watson, who works from home, said he noticed the effect of the lack of sunlight, compounded by the stress of dealing with his real estate agent.
"It was truly really depressing. My friends and family kind of noticed that I was a bit down all the time," he said.
"People were offering and encouraging me to come and stay at their place for a bit."
Associate Professor of psychology at Monash University, Sean Cain, has studied the impact of light on the circadian clock, which dictates how parts of the body function at different times of the day.
"All of our body is expecting bright days and dark nights. And so if we don't get enough bright light in the day, and we get too much light at night, it is disrupting this entire system of clocks," Dr Cain said.
Dr Cain is part of a team that has conducted the largest known analysis of light, sleep, physical activity and mental health, involving more than 86,000 people.
"The brighter your daylight, the less risk of especially things like depression, self harm, PTSD," he said.
While it is possible to mimic sunlight using artificial lights of 100,000 lux enriched in blue wavelengths, he said it would be extremely unlikely home lights would reach this level.
It is early days, but Dr Cain said work is being done to set minimum standards for the amount of bright light in homes and workplaces.
Challenging a proposed development
Planning laws in NSW require new apartment buildings to limit overshadowing of neighbouring buildings.
The existing homes must retain a minimum of three hours of solar access to the main living areas between 9am and 3pm on the winter solstice.
However, Sydney-based strata lawyer Stephen Goddard said this was rarely tested in the courts and a challenge would likely be unsuccessful.
"It's a vexing issue that has not been adequately addressed by the parliament or the courts," Mr Goddard said.
"I have seen brick walls constructed in front of windows and there was nothing the person suffering the loss of air or light could do about it."
In that case, a Surry Hills terrace extended into its backyard blocking the bedroom window of the neighbouring terrace.
Residents may have more success objecting to councils.
In March, Merri-bek council rejected a proposed seven-storey apartment building after a family objected due to the reduction in sunlight to their backyard the new building would have caused.
While Mr Goddard understood why people wanted to preserve access to sunlight, he doubted the law would back them.
"We do not have a right to a view — that has been well established. If you can't reserve a view why should you be able to reserve light and air?" he said.
He believed few property owners would be prepared to find out if he was right due to the costs involved in taking on a developer in court.
