The Hive thermostat was a purchase that I had been putting off for a long time. I didn’t have a thermostat in my house, just a basic programmer on the wall in the kitchen controlling my combi boiler. This had been working fine, but more and more often I found myself thinking a smarter system would be better.Sometimes, on a lazy weekend, I would sleep through the morning blast of central heating for the house to have cooled again by the time I got out of bed – a waste. Other times, usually in the evening, the programmer would switch the heating on despite nobody being home – another waste. And, of course, on more than one occasion I had boosted the heating on a particularly cold morning and forgotten to switch it off before I left, leaving the heating on all day – a huge waste.On top of that, a lack of a thermostat in my case meant that as soon as the house reached an adequate temperature I would have to nip into the kitchen to switch it off again. So, when the Hive went on offer (20% off, £199), I decided to take the plunge.The Hive unit arrived on time as expected from Amazon. Inside the box for my version was the thermostat unit, and instruction leaflet, and a second leaflet with a scratch-off code explaining how to arrange an installation (there are batteries in this box too, which I only found much later – make sure you check underneath the cardboard inside).You use the scratch-off code to “purchase” the Hive on the Hive website which is slightly confusing, but a cost at the checkout of £0.00 reassured me I was doing the right thing. The lead time is obviously going to vary by demand and location, but thankfully I got exactly the day and time slot I wanted the following week.The engineer arrived bang in the middle of the time slot and was very professional and efficient. It didn’t take him long to install and I looked on thinking I could have done this myself, but I still think the cost of installation is well worth it.This was about 10 days ago, and since then I have been wondering why I didn’t upgrade sooner. It has been bitterly cold this week (“Beast from the East 2018” – currently stuck indoors hence writing this long review) so my new heating system has well and truly been put through its paces.I’m finding that I don’t really rely on the thermostat function – instead, I typically use the thermostat as a remote boost button. Most of the time, however, I use the iOS app on my phone. It’s impressively responsive. I was expecting lag, but it’s instant. You press the boost button on the app and the boiler clicks on – there is no delay. The app isn’t perfect but it is usable and has so far been reliable, which is all you can ask for really.When I was researching the Hive, one of the things I wanted to know was how robust the overall system is. Having now used it I am satisfied that it is as least as reliable as the system it replaced. If you cannot access your app or the internet goes down for whatever reason, your thermostat will still work. If your thermostat dies, there is a button on the receiver that you can press to manually turn on your heating (if you’re wondering, the wireless thermostat is point-to-point with the receiver – it doesn’t use your wireless network). This layered approach to heating control appears to have been designed well and I’m more than happy with it.So the Hive has proven, for me at least, to be convenient, but how much money will it save? The box suggests “up to £130 per year”. Obviously, this is going to vary WIDELY from house to house, but I can share with you my very rough estimate. Based on my usage pattern and with help from numbers off my smart meter, I reckon over the coldest 6 months of the year I could save approximately £1.00 per week, or £26 over the whole year. This might not sound like a lot, but over 5 years even my conservative estimate goes a long way towards offsetting the cost of what I paid for the system. It’s worth noting that my energy company define me as a “low usage” customer (in other words, I was reasonably energy efficient to begin with). If you know you’re slack with your energy usage you could easily save more.So to wrap up, I have a very good early impression of the Hive system. If any problems or issues come out of the woodwork over time I will update accordingly.Recommended.