Product Review: Alcosense Lite breathalyser

Disclosure: I received a free sample unit for the purpose of this review. I received no payment and was not required to write a positive review.

The time difference between the UK and Brazil means that football fans will be watching some late games during the World Cup, many of them on weekday nights before work the next day.

Alcosense Lite breathalyser
The Alcosense Lite breathalyser

England’s second game is tomorrow night (Thursday) against Uruguay, and kicks off at 8pm — ideal timing for a few beers with the match. However, drinking on a ‘school night’ carries an extra risk — anyone who is driving early the next morning may still be over the limit.

According to Department of Transport figures, 21% of drink-driving road accidents now take place the morning after.

Late opening hours, coupled with the popularity of strong (5%+) lagers, large glasses of wine, house doubles and 35ml spirit measures mean that it’s easy to drink more alcohol than you realise. A healthy liver is generally able to break down one unit of alcohol per hour, after you have stopped drinking, but in reality, hardly anyone really knows how many units they’ve drunk — I know I don’t.

All of which means that personal breathalysers are increasingly popular. One of the most popular brands on the market is Alcosense. I’ve tested the company’s Lite model before, and recently had the chance to do so again.

Priced at £39.99 at shops such as Boots and Halfords, the Lite is affordable — but is it accurate and reliable enough to trust?

How does it work?

The Alcosense Lite is very easy to use. Once you’ve unpacked it, all you need to do is pop in 3 AAA batteries, wait 10 minutes while the unit performs an Automatic Sensor Clean and then you’re good to go.

A pack of five reusable blow tubes is provided, and you simply insert one of these into the socket on the unit and then press the power button, wait for the bleep, and blow, while holding down the ‘blow’ button.

The unit beeps when you’ve blown into it for long enough, and your blood alcohol level is then shown on the screen — a reading of 0.8% equates to the current UK legal limit.

Results not as expected

It’s quick, easy and potentially reassuring — except that my test readings varied quite widely, despite my not having had a drink for three days.

It did work correctly for my wife, straight away, and in fairness when I tested this device previously, it also gave a ‘no alcohol’ reading when I expected it to.

However, this time, the Lite didn’t fill me with confidence — over a period of around an hour, my readings gradually dropped from 0.4% to LO (below 0.2%, the lowest reading possible).

I knew I didn’t have any alcohol in my bloodstream, so I then wondered if something I had eaten for lunch was causing the problem — the only thing I could come up was the generous amount of vinegar I’d put on some fish, several hours earlier. Internet searches suggest that breathalysers should compensate for the effects of acetic acid (in vinegar), which can appear similar to alcohol to breathalysers, so I don’t know if this could have been the problem.

How accurate is it?

This experience highlighted my two biggest concerns with this type of low-end breathalyser: accuracy and reliability (over time, will it stay accurate?).

Perhaps the easiest way to explain this is to say that the type of handheld breathalyser used by the UK police costs around £800, and needs regular calibration. A similar model with the same accuracy, but more basic functionality, still costs £340. If that’s what it takes to get an accurate reading, what can you expect for £40?

One clue comes from the Alcosense Lite’s specified accuracy. According to the Alcosense website, the Lite is accurate to +/- 0.2% BAC. Given that the UK legal limit reading on the Lite is 0.8% BAC, this means a reading of 0.6% could actually mean anything between 0.4% (legal) and 0.8% (illegal).


I think it’s fair to say that for morning after use only, the Alcosense Lite is better than nothing. If you use it on the basis of only driving when you get a LO reading, it should be a useful aid.

However, I wouldn’t want to rely too heavily on a device like this, given its low specified accuracy, and the apparent potential for inconsistent readings.

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