I have had three different programmable t-stats in my last three houses, and they all sucked in some big way. They were cheap, but did save because of the timers.
None of them offer the flexibility that we as PLC guys are accustomed to.
Why not be able to schedule on any repeating period any sequence of up to 128 steps? And in each step set a cooling setpoint, a heating setpoint, a fan command, outside damper signal, let's see what else can we stick in here?
In OkieLand (the land of bugs, weeds, and toll roads, heat waves, hail blizzards, droughts, tornadoes and floods), there are at least 3 or four days a year when you need to heat and cool in the same day, or you or your loved ones are going to suffer.
Ten years ago I worked a 12 hour rotating shift schedule that alternated between nights and days every 7 days and repeated every 28 days with a long (7-day) break. I lived alone with the kids on weekends. There was no off-the-shelf residential t-stat at that time that would accommodate that kind of schedule.
On the subject of floor heating, are we talking about heating a concrete floor with liquid via radiant heat from a copper pipe?
I have been in a shop where the guy just used a household thermostat and small water heater and a itty bitty circulation pump. He wired the pump to be triggered by the fan output of the thermostat and insulated the heater.
I think he said he kept the shop floor at about 70 degrees and it was very nice working on vehicles in the dead of winter and warmed the whole room with the doors closed. I would think that if you used a PID for the water temp, you *might* could make it more efficient, but he said it was very cheap to operate, and his water heater was set on a fixed temp.
