Do green features add value to property?
The question of whether 'environmental' features add financial value to buildings, and if so, how much, came under the spotlight at Sustainable Business - the Event this week.
"There's a lot of work going on at the moment about whether sustainability is a worthwhile thing to pursue, particularly given the perilous state of the property market," he said.
He said that market research suggested that most companies looking to buy or rent commercial property said that sustainability was already a critical issue or would be in the next two years, and most said they would be prepared to pay more for eco-friendly buildings.
But when it came to signing the cheque, he said, the enthusiasm tended to evaporate.
"When it comes to for it or signing the lease there seems to be a difference of opinion," he said.
He questioned the usual perception that sustainable features always had to mean a higher price tag and said that the shrewd companies acknowledged that even if there was not a premium to be earned for green properties in today's climate, there would be in tomorrow's.
Reliable research into just how much value these features might add was still thin on the ground, he said, pointing the four papers from the US that had interpreted the same data set in radically different ways, with one claiming green buildings were worth a third more while, at the other end of the scale, another claiming there was no noticeable difference in value.
Despite the recognition that the evidence is still rather patchy, Mr Keeping said he was confident that with all the drivers pushing in one direction - from consumer expectations to government regulation - the demand for green buildings, and a willingness to pay for them, could only increase.
"I still say there's a lot to play for," said Mr Keeping.
"The savvy investors tell us 'we're okay with the fact that there no evidence at the moment because we're convinced there will be soon'."