Not very reliable. 2

Pros: nice product, clear display and large characters, setting single road with the booklet provided with the product; works throughout the house on different floors; recording the minimum and maximum temperatures in and out resettable; temperature displayed near 0.1; measurement of the outside temperature every 4 seconds; (Indoor: every 20 seconds).
Cons: I compared with a conventional thermometer with liquid and another circular and the temperature displayed by the unit is higher than the liquid thermometers and mechanics: more than 1 ° C (see 1.5 ° C). I conclude that it is accurate and gives a higher temperature than other thermometers (at least + 1 ° C). The manufacturer states that the margin of error is +/- 1 ° C. The display in and out do not give quite the same temperature when they are side by side approximately +/- 0.8 ° C (or worse).
But hey, at this price, you can not have high-end ... Conclusion: Good product but too optimistic and very precise. It all depends on what one wants to do.