Last year, the company trialled two virtual StyleMe mirrors, developed by Cisco, with bespoke built-in 3D cameras to capture shoppers' dimensions and superimpose a virtual outfit over their reflections.
But speaking at the Retail Business Technology Expo conference, Burnett said the project failed to make any money.
He said the company was keen to do as many trials as possible, but "the key is, when you find it a dud, stop".
"The magic mirrors allowed us the opportunity to trial. We tested the hypothesis, it failed, and we got out quickly," said Burnett. "Failing fast at innovation is really important. You can waste a lot of time and energy if you don't.
"It didn't create a compelling and sustainable [proposition] for us. But it created theatre in stores, which is something all retailers want," he added.
Moving to the cloud
The news comes as retailers are increasingly looking at innovative ways to entice shoppers in-store, as the high street is haemorrhaging cash to online competitors.
John Lewis, however, is considered to be one of the few retailers getting the multi-channel offering right, with online sales having recently grown by more than 40% year-on-year.
Burnett said the company currently spends tens of millions of pounds keeping the lights on in a costly and complex IT estate. As such, he said the company was looking to reduce its ownership costs by moving to the cloud.
We can't spend time and money looking at things not aligned to the business strategy
Julian Burnett, John Lewis
"There are faster and more flexible models of provisioning desktop and corporate applications," he said.
John Lewis is currently running a 6,000-person trial for Google Apps, with email and calendar functions. "We are looking to move IT investment outside the perimeter of our datacentre so we don't have the hassle of maintaining tin and wire," said Burnett.
It is also looking into Microsoft Azure, SalesForce.com, and Amazon Web Services, he added.
"The pace of change is so dramatic, our ability to respond makes it impossible to acquire assets, put them together, install them in our datacentre and then provision them to our users and customers," he said. "The ability to spin up capacity in infrastructure is incredibly valuable to us."
Technology is driving the business strategy, but must also be aligned with it, said Burnett. "Unless we have a clear line of sight, we can't pass go. We can't spend time and money looking at things not aligned to the business strategy," he said.
Burnett said the company would not look at any new technology unless it added value to customers across all its channels, enabled it to streamline services and could sit comfortably within John Lewis's architecture.
"Innovation is a double-edged sword," he said. "It is absolutely necessary to differentiate ourselves, and we strongly believe technology will allow us to do that. But the challenge is getting it to co-exist in the company's complex architecture, resulting from 50 years of IT investments.
"We have to filter out the noise and focus on things that will give us the biggest competitive advantage."
Knowing where to invest
Other areas of innovation include using technology to allow retailers to see where customers are physically in store to help it plan the use of space more effectively. "Because space is a premium, and costs us a lot, we need to know we are getting the maximum value," said Burnett.
"Everything we do, in terms of technology innovation in the front of the business, is all about creating an attractive, engaging experience for customers," he said.
The retailer is currently implementing a second-generation kiosk in the form of a plate wall, which allows customers to view its full range of crockery and order sets to be delivered.
On the subject of mobile payments, Burnett said the company is holding back on investment in mobile payments, as the market is currently crowded and it is not yet clear which form of payment will prevail.
"It's a big bet to place on a particular technology in this space," he said. "There is a load of stuff going on behind the scenes, whole new models for providing services [to our] 30,000 people who use IT."