one should really think about what exactly one wants to accomplish. Most people think, they should have a controllable thermostat so if they are not in the house, the house doesn't get heated as much. However, there are quite a few statistics and reports floating around that say, it makes more sense energy wise to keep the house heated at all times to a specific temperature, than to change it multiple times over the period of a day. i.e. the energy needed to reheat a house is much more, than the energy needed to keep the house at a specific temperature. There is very fine line where there is very little gain in using those controllers you are looking into, but the costs associated with them, and the time it takes to finetune them to their optimal behavior, is better spent in making sure, other energy efficiency measures are undertaken. Maybe not as fancy, but probably way more efficient. Like getting better insulation, a new heater, stuff like that.