According to research firm Juniper, about three million virtual reality headsets will be shipped next year. That’s not exactly record- breaking but it’s a significant start, and if things go as expected, it could rise to 30 million by 2020.

There are other, more optimistic estimates for sales in 2016. According to TrendForce, that figure could be 14 million units in 2016, with 38 million shipped by 2020.

According to IHS Technology, most of the headsets shipped next year will be smartphone-based, with sectoral sales worth an estimated $1.1 billion (€1 billion) in 2016.

Regardless of whose estimates you trust, it’s an emerging category that few companies hoping to get on board with VR can afford to ignore.

Look at who is getting involved. Facebook put its money where its mouth is with Oculus. Sony is investing in PlayStation VR. Microsoft is covering all its bases with its own holographic computer system, HoloLens, and a partnership with Oculus for streaming games from the Xbox through Windows 10.

Mobile maker HTC has partnered with Valve to create the Vive headset, while Samsung has hooked up with Oculus to create the more affordable Gear VR.

Apple is getting into virtual reality too, with a collaboration with U2 on a 360 music video for the Vrse app. U2 fans could board the Experience Bus outside U2 concerts, don Oculus headsets and get right into the Song for Someone video.

Earlier this year, the company submitted a patent for a virtual reality headset, and in the past few years has been buying up companies such as PrimeSense, which designed motion sensors for the Xbox's Kinect accessory, and Metaio, an augmented reality firm.

There are many more start-ups and smaller firms that are laying bets virtual reality will be the technology of the future. But just because the companies are investing, it doesn't immediately follow that virtual reality will be a hit with consumers. Look at 3D for example. While the major TV manufacturers got behind the technology, it has failed to revolutionise the living room as much as they hoped. Even in gaming, it has failed to find its footing. A few years ago at Consumer Electronics Show, attendees were being shown TV after TV with 3D built in; at video game trade show E3, Sony made a point of featuring 3D games during its press conference. But fast forward a few years and few people are still banging that particular drum.The movies still hit the cinema, but the notion that a large number of people would replace their perfectly good HD TVs with new 3D-enabled ones simply hasn't panned out.

If virtual reality is to avoid the same fate, consumers are going to need to see compelling content – and that includes built for VR rather than simple ports of existing content – and affordable equipment that won’t break the bank.

Content will be key. The technology has for the most part been concentrated on consumer usage and games has been the obvious fit. According to IHS, the paid VR games market will be worth almost $500 million next year. And if the firm is right, Sony may be the initial leader in the sector, outselling both Vive and Rift headsets – at least initially.

But there will be wider uses for VR outside the entertainment space. In business, the technology could be used to test products without the need to develop a number of prototypes, or to create training programmes for staff. The devices could also be used as training aids in sports or medicine. In construction, it could be used to create virtual buildings to pinpoint problems before expensive building work takes place.

Already companies such as holiday firm Thomas Cook have trialled Oculus Rift headsets to give virtual tours of some of its resorts. Car manufacturer Ford has used the Facebook-owned technology to develop its products, examining how the interior and exterior of the car looks in great detail on virtual prototypes. Mercedes Benz developed an app for Cardboard that allowed you to experience a test drive in one of its cars, while Lexus is using virtual reality to show case its new range

Virtual reality, it seems, is already taking hold. Virtual reality: From DIY to high-tech Cardboard The most affordable at $25 of all the virtual reality options, Cardboard is Google's basic 3D viewer. It's not the most attractive or high-tech option, but it works.

Essentially a cut-price headset made from – obviously – cardboard, it’s a bit of a DIY project. When you get it, it’s flatpacked, so you have to assemble it yourself. You need a phone that will fit inside Cardboard, which is currently any smartphone with screens up to six inches in size, and a few Cardboard-compatible apps on your phone. That can be anything from YouTube 360 to a version of Crossy. Basic but a good introduction.

Samsung Gear VR Samsung's virtual reality headset may need a smartphone to work, but that's all it has in common with Cardboard.

The Gear VR was developed with Oculus and uses the Galaxy S6, S6 Edge, Note 5 or S6 Edge+ as a screen.

The consumer version of the headset is now available for €99, and it’s had a few tweaks from the developer release.

The biggest change is that one headset is now compatible with a number of handsets; before, you needed to change headset if you were switching between a Galaxy S6 and a Note. Now all you need to do is adjust the clip size to the handset you are using.

There is a content store with apps for the VR, ranging from games to entertainment, and you can even watch your Netflix favourites in a virtual theatre.

An optional game pad opens the system to games aside from Temple Run VR and others that can be played using the integrated touchpad. HTC Vive HTC may not have originally been the first name that sprang to mind when VR was mentioned, but its Vive headset has certainly been turning heads. It’s a collaboration with games firm Valve, and although it’s not available until next year, early indications are that it will be good. The Vive uses a combination of the headset, two controllers and some cameras to set up your play space. The controllers give you a way to interact with your environment, while the cameras provide a boundary for your game space that will show up in the game and stop you from walking into a wall.

PlayStation VR Formerly known as Project Morpheus, Sony's virtual reality project is concentrating, unsurprisingly, on games. It works with the PlayStation 4, Sony's newest console, and allows multiple players to compete in the same game space. It's expected to launch in the first half of 2016, and there's no firm details on pricing yet, although a cost similar to a console has been mooted as the likely price tag.

Oculus Rift The one that kickstarted the current chase for VR, Oculus is now owned by Facebook. Its virtual reality head-mounted display Rift will be PC based, supporting game streaming from the Xbox One through Windows 10. It has positional and rotational tracking, OLED panels and integrated headphones with real time 3D audio effects. Each Rift headset will ship with an Xbox wireless gamepad in the box, and Oculus has also developed two controllers, known as Oculus Touch. The consumer kit is due to go on sale early next year, although with a powerful computer needed to run the software correctly, chances are it's going to cost you more than €1,500 for the total package.

Microsoft HoloLens Strictly speaking, HoloLens isn't virtual reality. Microsoft is billing it as a holographic computer that allows you to team high-definition holograms with the real world. So you could have a Skype conversation, "send" objects to people that can then be 3D printed in the real world, create a building design by integrating it into real-world street views or simply play games. There's even talk of Microsoft's digital assistant Cortana being given a life-size hologram of her own, although that's still just an idea suggested on the Share Your Idea website for the platform.

The first development kits are expected to ship early next year, so a full consumer release is still a way off.