It may not be the most glamorous deployment for the technology, which uses the screen of the headset to mix digital objects into the user's field of vision. The practice is usually known as augmented reality (AR), although Microsoft prefers the term 'mixed reality' for its headset.
But that's perhaps the point. Until now, much of the attention has been on the gaming and entertainment potential of virtual reality (VR). VR headsets block out the outside world entirely to allow users to focus on battling robots or aliens, for example. But Microsoft has been focusing more on the potential uses of AR for business, which are less exciting but may offer a better path to success.
For example, elevators are big business: the market for servicing them is valued at over $44bn a year and the world's 12 million lifts transport over one billion people each day, making elevators the most-used means of transportation on the planet.
"We never realise how relevant elevators might be in our day-to-day life until they are out of service," Javier Sesma Sanchez, general manager of the Thyssenkrupp elevator innovation centre, told ZDNet.
However, those lifts aren't always working: worldwide there are 180 million hours of elevator downtime every year, which means your lift might be out of service three to five times a year.
When a technician is troubleshooting at the site they might not have the information available or might need to be guided through the process needed to repair the lift. However, when fixing elevators, engineers were still using smartphones and laptops to access information "with the phone close to his ear and two hands trying to fix the elevator," said Sanchez.
About three years ago, the company started working with Microsoft on connecting elevators to the cloud to reduce downtime -- by predicting failures in elevators before they happen. "We don't have a technician sitting at every elevator worldwide," said Sanchez.
Thyssenkrupp started working with HoloLens because it could allow engineers hands-free access to data about the repair and also allow -- via Skype -- engineers to call in other experts who could, through the headset camera, see what the engineer was seeing.
"Why HoloLens was interesting for us the first thing was a full Windows 10 computer it's untethered so it can be used with the built-in applications, you can do a Skype call. It becomes another set of eyes," he said.
"Our first experience of HoloLens was bringing mixed reality to our technicians to be able to reduce downtime. This is something you can only do with mixed reality," he added.
"The feedback we get is superb because the operation can be done safer, because [the technician] can have his hands free, and secondly, they feel backed up because they can connect to anybody in an efficient way."
In a trial, an engineer using HoloLens to communicate with a colleague for the first time was able to solve a fault that normally would take two hours -- or even require having another engineer on-site -- in 20 minutes.
The company now has 100 HoloLens units in use by its maintenance teams in the field. "They are using that and we are getting constant feedback," said Sanchez. The company had more than 24,000 service technicians worldwide, so it's a modest rollout so far, but Sanchez said the headsets have potential in other areas, such as training technicians, too.
"A machine that is maybe two metres by two metres, that's an asset you cannot bring into the room for training, but you can bring a one-to-one digital model and make an explosion of all the parts and move around in an object, which is a hologram made of light. That creates a completely different way of training."
The company has also been using HoloLens in its chair lift business since April in Germany, the Netherlands, and Spain. Because the headset superimposes digital objects on the real world, it has to be able to measure physical objects so that digital objects can seem to interact with the real world -- like placing a virtual book on a real table.
This feature also can be used to measure and scan the staircase of a customer who wants a stairlift fitted in less than ten minutes, and then the headset can show the customer a hologram of how the stairlift would look in their house.
Previously this would be done by using a box of 100 markers and taking photos, which would then be used to make a 3D model of the stairs, which a salesperson would then have to take back to the customer. "We are able to reduce lead times by 4x," said Sanchez.
"Imagine the first time we show this HoloLens to somebody of 70, 80 years old so they can see a hologram in their living room, it's a very different way. They really enjoyed the process, being able to see the chairlift in the home."
It's still early days for AR, which is harder to build than VR because it also has to take into account the real world. For example, the kit is still extremely pricey -- £2,719 for the HoloLens developer model, and £4,529 for the commercial model featuring additional security. Microsoft only recently opened up a new partner programme to encourage integrators to build and sell packages based around the headset.
But other early adopters of the technology include Japan Airlines, which built a proof-of-concept training programme for flight mechanics, and Volvo, which tested out a showroom app.
Tech analysts IDC predict that 20 million AR headsets will be shipped by vendors including Microsoft in 2020 -- up from a mere 210,000 last year. But that's still modest compared to the 67 million virtual reality headsets that IDC thinks will be shipped in 2020.
"The reason for this is not that AR is less important, but rather it is harder to achieve... AR in general will have a much bigger impact overall on the industry," IDC said.
So it could be in niches like elevator repair -- and not the consumer gaming side -- that augmented reality has its first tangible successes.