TV buying guide: Everything you need to know before buying a new television

Do not buy a TV without reading this first

For things you mostly just want to sit back and watch, televisions have become hellishly complicated to buy. Within minutes of dipping your toes into TV buying waters these days you’ll find your head swimming with so many acronyms and so much brain-melting jargon that you may well end up deciding to bury your head in the sand and stick with what you’ve got.

This, though, would be a real shame. For lying behind all the complication are some truly outstanding TVs capable of making your old set look like a relic from the stone age. With this in mind, we’ve put together this simple but comprehensive guide to all the latest TV tech that matters. By the time you’ve finished this you’ll be a TV salesman’s worst nightmare: a consumer who actually knows what they’re talking about…

Screen size

The range of screen sizes available today is immense, taking in everything from 14 inches to more than 100 inches. So how do you figure out the optimum size for you?

While some will always recommend going for the biggest screen you can afford that doesn’t spread over windows or doorways, there are a couple of different formula out there you may find helpful if you want a more scientific approach. 

According to THX, you should divide the diagonal width in inches of a screen you’re interested in by 0.84, with the result giving you the number of inches you’ll ideally be able to put between you and the screen. Using this method, if you get a 65-inch TV you should sit around 6.5 feet from it, or more likely you can perform the opposite calculation to choose a TV once you know how far you're able to sit from it. 

We suspect 6.5 feet will be a bit closer than most normal viewers will be comfortable with for a 65-inch TV, though. So another common calculation you could try is a seating position between 1.5x and 2x the diagonal width of your screen. Using this approach, a 65-inch screen would work for a viewing distance of between 8.1 and 10.8 feet. 

Time to get your measuring tape and calculators out, people.

Wall mounting

Many people think they’d like to wall mount their new flat TVs. However, research suggests that when it comes down to it, precious few of us actually do.

If you’re positive this will work for you, though, there are a few things to consider. First, remember that the TV will be right up flat to the wall, so you might want to go up a screen size or two. 

Second, think about TVs designed to be used with ultra low profile mounts, so that they stick out as little as possible from the wall. Or, given that many TVs don’t ship with wall mounts included, if you want to be able to choose from a wide selection of mounting options at a range of price points, look for a TV with wall mount screw positions compatible with the ‘VESA’ industry standard.

One other thing to bear in mind if you’re thinking of wall mounting a TV is a set’s realistic viewing angles. Especially vertical viewing angles if you’re thinking of mounting a TV above a fireplace (which is not something we’d typically recommend).

Panel technologies

There are two types of TV technology you need to understand: LCD and OLED. Plus there a couple of important variations on the LCD side. 

LCD/LED TVs

LCD/LED TVs use panels of liquid crystal pixels illuminated by external light sources. The liquid crystals rotate round to let through the amount of light needed to illuminate pictures correctly, with external filters creating colour. 

The main advantage of LCD TVs are brightness, affordability and durability. Their main disadvantages are limited viewing angles and difficulties controlling light in the picture due to the use of external light sources.

There are two types of LCD panel: IPS and VA. IPS types are predominantly made by LG Display, and feature in all of LG’s LCD TVs, plus some (usually affordable) models from other brands too. VA panels are more widely used, and are made by a variety of manufacturers. 

IPS panels offer slightly wider viewing angles than VA panels, but struggle with contrast. VA panels up to this point feature narrower viewing angles, but generally produce much better contrast.

OLED TVs

OLED TVs use a system of organic phosphors in self-emitting pixels to enable each pixel to generate its own light, completely independent of its neighbours. This allows for vastly superior contrast and light precision than you can get with even the most advanced LCD TV. It also means OLED TVs can be watched from much wider viewing angles than LCD TVs without colour or contrast reducing. These features have made OLED popular with many serious AV fans.

However, there are issues with OLED TVs too. First, while prices have dropped over the past couple of years, they’re still substantially more expensive than typical LCD TVs (though some are now cheaper than high end LCD TVs). 

Second, OLED TVs currently can’t get nearly as bright as LCD TVs - something that could become an issue with HDR content. 

Finally, there have historically been issues with lifespan and image retention (where bright image elements can ‘burn’ into the screen’s phosphors if left on for too long). However, LG, the main manufacturer of OLED screens, claims to have fixed these lifespan/image retention issues, and we haven’t seen any evidence recently that might counter those claims.

For a full rundown, check out our guide to OLED TVs

Backlight technology

A key point to consider if you decide to buy an LCD TV is how the LCD panel is lit, since this can have a large impact on the contrast the screen is capable of. 

Some use lights mounted on the edge of the screen firing across it (aka edge-lit panels), while some use lights mounted directly behind the screen. Generally speaking, TVs with lights behind the screen deliver better contrast than edge-lit models. But these models don’t generally feature such slim designs, tend to cost more, and often use more power.

One final option to consider with LCD TVs is local dimming. This sophisticated feature allows a TV to output different amounts of light from different sections of its edge or direct lighting arrays, and can dramatically improve contrast.

Connections

These days the main connections you need to check are HDMIs, USB ports and multimedia support. 

With HDMIs you’re talking about the number (try and get at least three) but also the specification. With 4K TVs, try and get a TV with v2.0 HDMIs rather than v1.4 HDMIs, to guarantee the best compatibility with current and upcoming source equipment. 

USBs ports are useful for both playing back multimedia (especially photos and videos) stored on USB drives, and, with some TVs, recording from the TV’s tuners to an attached USB hard drive. Look for at least two, and ideally three USB ports.

Most TVs now have built-in wi-fi and Ethernet ports so that you can connect them to the internet. Not all TVs, though, also let you use these network connections to access multimedia stored on other devices on your network. So if this is a feature you want, make sure the TV you buy supports it. Note, too, that some TVs additionally support Bluetooth communication with external devices.

Curved or flat?

Curved TVs are much less common in 2017 than they have been in recent years, with pretty much all manufacturers bar Samsung deciding that they’ve run their course.

If you are looking to buy a very large TV and/or you’re going to be sitting pretty close to your screen, the way the picture on a curved screen enters your peripheral vision can make for a slightly more immersive experience. Curved screens follow the shape of your eye, too, arguably making the corners of the picture look sharper than they do on flat TVs. Plus curved screens tend to suffer less with colour and contrast loss when viewed from an angle.

However, there are issues with curved TVs too. First, they tend to distort any onscreen reflections so that they cover much more of the screen than they would with a flat TV. Second, if you watch from an angle of really much more than 20-25 degrees, the picture can start to look foreshortened. 

Finally, if you’re not sat in the optimal position (if you’re either too far back or off to the side), curved TVs can distort the picture’s geometry.

Resolution: Ultra HD vs HD

There are two resolutions to choose from right now: Ultra HD (also known as 4K), and HD. Ultra HD TVs carry 3840x2160 pixels, HD TVs carry 1920x1080 pixels. This means Ultra HD TVs have four times as many pixels as HD ones, and so can deliver pictures with much more resolution. 

With native 4K sources starting to become more common now (Netflix, Amazon, Ultra HD Blu-ray and Sky Q in the UK) and the prices of 4K TVs plummeting, we’d generally recommend that you buy a 4K TV even if you don’t currently have any access to 4K content. Especially if you’re looking at a TV of 50 inches or more. 

While I’d recommend 4K for a main living room TV now, though, HD TVs can be good bargains for second rooms. 

HDR

High dynamic range (HDR) is the latest technology to arrive on the TV scene. HDR TVs are able to produce pictures that contain much more brightness and contrast than normal TVs - so long as they are fed HDR content that contains this extra luminance data. 

All current HDR TVs also support wider colour spectrums (often described as wide colour gamut, or WCG - essentially meaning that ) than most non-HDR TVs - which is handy, as pretty much all HDR content also carries wide colour spectrum picture data.

There are currently three types of HDR. HDR10 is the industry standard, and all TVs support this. Dolby Vision adds an extra layer of information that tells a TV how to render pictures on a scene by scene basis. Only some brands - most notably LG, Vizio, TCL and (via an upcoming firmware update to some models) Sony - support this. 

Finally there’s Hybrid Log Gamma (HLG), designed for HDR broadcasts. The majority of TV brands have pledged support for this via firmware updates in the course of 2017.

For a full rundown of the technology check out our full guide to HDR

Quantum dots

Some (usually high end) LCD TVs have started to use Quantum Dot technology to deliver wider colour ranges than you can get with normal LCD panels. Quantum Dots are tiny particles ranging from 2 to 10 nanometers in size, with each size capable of emitting a different colour. Using them allows LCD TV makers to avoid colour filters and white LED Backlights - two things that typically limit an LCD TV’s colour performance.

Samsung is the biggest advocate of Quantum Dot technology, with its 2017 ‘QLED’ models using a new metal-coated type of Quantum Dot that can produce a much wider colour range, more brightness and a wider viewing angle than traditional Quantum Dots. Quantum dot TVs are generally markedly more expensive than normal LCD TVs, though.

There are alternatives to Quantum Dots when it comes to expanding colour range. Some TVs - including Sony’s recent Triluminos models - use wide-range phosphors. LG, meanwhile, will be using Nano Cells in its high-end LCD TVs for 2017. These alternatives to Quantum Dot technology use same-sized dots just one nanometer wide in conjunction with normal colour filters - a combination which LG claims enables its new Super UHD TVs to deliver better contrast and more balanced colours.

Brightness (nits)

A screen’s brightness (as measured in nits) has started to become a big deal with the arrival of HDR, with many HDR proponents - including, especially, Dolby - stating that we’re about to enter a ‘nit race’ where TVs push to constantly get brighter. 

The brightest LCD TVs (Samsung’s upcoming ‘QLED’ models) can get as bright as 2000 nits. The 2017 generation of OLED TVs are reckoned to get to between 800 and 1000 nits.

Contrast ratio

Few TV brands still quote contrast ratios. But if you do see one, it’s basically a calculation of the difference between a screen’s deepest black and brightest whites, written as, for instance, 10,000:1. It’s generally worth taking these figures with a pinch of salt, though, as they can be measured in multiple, very different ways.

Speakers

The sound quality of flat TVs can vary immensely. So if you’re not intending to use some sort of external sound system, this is something you should pay attention to.

Most brands quote a number of Watts of power for their TV speaker systems, but this is seldom helpful in deciding how a TV is likely to sound. 

Look instead, for instance, at how many speakers a TV has, and the configuration of those speakers. For instance, a ‘2.1’ configuration would indicate stereo main speakers with the ‘.1’ bit pointing to a dedicated bass speaker. Or a 3.1 configuration would point to a dedicated centre or dialogue channel alongside stereo and bass speakers.

Subwoofer speakers for bass are always welcome given how much TV speakers generally struggle with the lower end of the sound spectrum.

Another audio issue is the way the lack of room available to speakers in thin TVs means they usually have to fire their sound downwards. Yet this can lead to an indirect, muffled, weedy sound. TVs that manage to provide forward firing speakers tend to sound much cleaner and more powerful.

Some TVs of late have even gone so far as to ship with sound bars that either hang off their bottom edge or sit separately below the main screen frame.

One final word of warning here is that you should treat the claims of TVs to offer DTS or Dolby Digital surround decoding with scepticism. No TV can deliver anything close to a proper surround sound experience from its own speakers without using actual rear speakers, and many sound pretty horrible if they try. Experience shows that a good stereo sound - especially with a subwoofer to add bass - routinely trumps a half-baked pseudo-surround sound system or mode.

Smart TV

Almost every TV these days can be added to your broadband network to enable the use of online features or, in some cases, access media files stored on other storage devices - mobile phones, tablets, NAS drives etc. This sounds great on paper, but in reality the quality and usefulness of such ‘smart’ features can vary greatly.

Generally speaking, if you have a number of personal smart devices in your home, TVs that can access content on other devices in your home - including via Bluetooth as well as wi-fi - are worth looking out for.

Where online features are concerned, don’t be seduced by app quantity. The vast majority of TV apps are borderline pointless, and just clutter up the smart interface. App quality is much more important. In fact, for many households the only online features that really matter are online streaming/catchup services. Especially Amazon Prime, Netflix, and catch-up services for your region’s broadcasters. For instance, BBC iPlayer, the ITV Hub, All4 and My5 in the UK.

Finally, the simplicity of a smart TV interface plays a key role in how much you might use it. Currently LG’s webOS and Panasonic’s Home Screen 2.0 systems handle their content most effectively. 

For a full breakdown of how the various manufacturer's smart TV interfaces stack up check out our best smart TV platform guide

What's next

Phew, We’ve now covered the important stuff you should think about at the very start of your TV buying quest. On the next page we’ll talk about the sort of things you should try and look out for once you’re actually standing in front of a TV you’re thinking might be the one for you.