The inventor of a model to work out how much the loss of sunlight costs a homeowner says he is confident it accurately shows denser housing is a plus.
The model has been used to weigh up law changes before Parliament paving the way for three 3-storey houses on one section.
Kirdan Lees of Sense Partners said they wanted to test how much shade these might cause, within a 50 metre radius of a new development up to 12m high.
"It's not a small amount - so we're talking about half a billion dollars in terms of shading costs," he said.
"But when we look at the benefits - allowing people to live closer to work ... closer to other people, cheaper housing - actually dominate the cost in terms of loss of sunshine."
The trailblazing model developed by the Wellington firm specifically to cost the policy, factored in the feel-good nature of sunlight by assessing the lost market value of a house that got less light, Lees said.
"We really need to think about ... how many hours, what part of the day do we lose.
"And ... how do people price, or feel about that loss of sun."
A colleague had just mentioned to him moving into a flat "because it had great sun", so it was important, he noted.
The benefits of the policy rang true even if the forecasts of how much development resulted from it proved to be off, he added.
Not enough work had been done in urban economics given the big changes in housing, Lees said.