For now, the big question mark when it comes to these elevators is cost. Bass indicated to Olley that there would be a "payback period" of three to four years to fund the elevators, but whether or not Multi will be more costly than cable-based designs is up for debate. However, Bass says Multi will be much more cost-effective than traditional elevators in the long run, as taller buildings use land resources more efficiently than shorter buildings, and they provide much more housing and space. Additionally, needing less space for elevators means saving much more money on overall square footage. "I looked at what the effect would be if we took out [most of the elevator shafts] in one of our buildings, and the net result is we would save 22,000 square feet of space," says Olley. "And in London that would be worth 1.5 million pounds."