This was faulty from the box. Shame really as I have had one for several years and is used every Spring to control a big heating mat I use for propagating. This one was to extend my ability to bring more plants on stream. I will be ordering a replacement as the thermostat I have has been faultless and I want another one. 5* for the one I have. Full marks for the Amazon returns system not had to use it before I did not know it existed until now and how easy it is.

Moyennement satisfait

Very precise temperature control

Zuverlässiges Produkt / würde ich jederzeit wieder kaufen / sehr weiter zu empfehlen

Just took delivery of a second Biogreen Thermo 2, having set up and used (successfully) the first one since November 2013. Both used to control heating in greenhouse - original for space heater and new one for soil-warming cable. Set up the new one exactly according to the instructions that came with it, only to find it would not store the set temperature (set at 20 deg C) but immediately defaulted to 10 deg C. Then I discovered that the instructions for setting the required temperature (page 12 of booklet) on the new one were wrong. These instructions said "Press the up or down button briefly to switch to setting mode. - - - Using the Up and down buttons you can change the temperature in 1 deg C steps. After you have set a new temperature it is saved automatically and the menu closes after 3 seconds." This did not work!However, as I had another, 16 month old unit I checked the instruction manual and found the setting instructions were very different - online were the same as the older ones and said: "Press the down button for 3 seconds to reach the setting mode. - - - Using the Up and down buttons you can change the temperature in 1 deg C steps. To store the selected temperature press the 'C/H' and down buttons simultaneously, (within 10 seconds, otherwise the set value will not be recorded)."The older instructions worked. Not too clever, sending out the wrong instructions but apart from this, they seem to be very good functional thermostats - that's why I bought the second one.

Feb 2021 editAll three still going strong. Two in the greenhouse and one in our conservatory.I see there are now many similar on Amazon at less than half the price- look at their 1 star reviews - these Biogreen units seem robust snd safe by comparison.Feb 3018 edit: just bought a third one when my propagator thermostat packed up. My two Biogreens are still working fine.In response to other reviewers comments, yes they are. ‘basic’ and the supply flex could be longer but I really don’t care a monkeys - in my limited experience with them - they work and seem robust - and I had gone through about three other branded thermostats over the years. You can’t link them into eg my z wave home automation either and no outputs to log temperatures but I don’t need these - I can run them off a timer or remote switch if I want to - but what I need is to be able to set propagator temperature and leave it for weeks without worrying that it may have packed up.I also haven’t found any equivalent unit short of commercial devices such as the Pola range etc.Previous review 2014:Had one for 2 years in greenhouse - solid construction. Bought another one for conservatory to replace a cheap underfloor heating thermostat that is unreliable.As other reviewers have noted - the instruction manual is wrong - you need to download the pdf from their site. In particular, to set the set point, you have to press and hold the down button for three seconds until the setpoint temp flashes and then adjust it by pressing the up/down button. To store the setpoint you need to press the down button and C/H button simultaneously, briefly - but within 10 seconds of adjusting the setpoint.One of the things I needed to check was that, in the event of a power failure, the set point is remembered. It is - at least for an hour minimum. I just tested that function.This is expensive but once you have got one I think you will feel confident in the unit. We used to design/make this sort of thing in the UK a long time ago but at least the Germans still know how to do so.Some reviewers comment on the fact that the flap over the outlet socket will not open enough to plug in an energy meter between the unit and the load - that's right - I have to use an extension cable - its a slight pain but I really haven't found any other unit that can do the job as well.Note that this is NOT IP 65 rated - it is for covered / indoor use - having said that, I have had it in my greenhouse for 2 years ( very damp/humid ).In terms of temperature accuracy, the display is to the nearest degree C and I have checked that out against a separate temperature sensor from 3 to 20 C and its pretty good. If you need control to better than one degree then you need to look elsewhere.I've given this 5 stars in spite of the manual - its just because I haven't found anything better with a similar quality and robustness.