I’ve had British Gas’s Hive system for the best part of a decade, and it more or less does the biz. I started with one thermostat, which is all you need in a flat, then added a door sensor.
More recently, though, the price of gas has gone off the charts just after I, erm, bought a bigger house. Since there’s only me here most of the time, some means of suppressing the heating in the rooms I’m not occupying at any given point seemed like a financial winner.
One can of course go round and screw the existing thermostatic radiator valves shut by hand, but doing that manually is a faff and you end up forgetting to do it. Which is here Hive comes in. The price per radiator for this convenience is robust, and I barely managed to save a tenner per unit over the new price by buying on eBay. On the other hand, strong second hand prices presumably indicate they’re considered worth having.
After about three months with them in place, they mostly do the business. My main gripes are all things that could be fixed in software (must send British Gas an e-mail):
- Give me a button to slave the valve onto the main thermostat’s schedule when I don’t need separate control for that room at the moment
- Make it respond a bit faster when boosting an individual room
- Give me an option to disable the controls on the valve itself doing anything, so guests fiddling don’t leave the settings how I don’t want them.
Overall, though, not bad. The batteries don’t last more than about eight weeks in rooms which spend most of their life on “frost protect” levels of heat, but that’s not a total surprise to anyone who’s tried to use battery power tools which live in a cold garage.
Incidentally, your boiler probably needs a minimum number of radiators “in-circuit” to run efficiently and avoid damage, so don’t go mad and fit these absolutely everywhere (the price should put you off doing that anyway). I have them on my office, spare bedroom and kitchen/dining room - all rooms which I spend large portions of any given day not making use of. Meanwhile the lounge and master bedroom are always on when the boiler calls for heat.
Difficult to be sure of the exact savings, but if nothing else, these get more heat to where you want it for the same expenditure.