We have designed the Celsia System to maintain room temperatures within a fraction of a °C. On the CZC1 and CZC3 the room temperature is displayed with a 0.1°C resolution and, once the room is up to temperature, it does not usually change at all.
Many thermostats have a switching differential (hysteresis) of about 1.5°C. This means they switch heaters on at full power until the room reaches the target temperature, then switch them off until the room has cooled to target temperature minus 1.5°C. As a result the room temperature cycles up and down by at least 1.5°, probably more because it takes time for heat to get from the heater to the thermostat.
Even a 1°C change is noticeable. For instance, suppose you find that 20°C is comfortable, but begin to feel cold at 19°C or 18°C. You would have to set a normal thermostat to 22°C to feel conformable all the time. But this is a waste of energy because for much of the time the the room is hotter than it needs to be.
Turning a thermostat down by just 1°C saves considerable energy. Celsia lets you do this because we have eliminated the temperature cycle altogether!
We have eliminated the temperature cycle by using technologies in both the heater PCB and the thermostat.
In our heater PCBs, we do not simply switch the heater on or off, we modulate the power; (for most heaters) all the way from 0% and 100%. We use a combination of methods to achieve this depending on the configuration of the heater. These include selective element switching, surface temperature control and chrono-proportional control.
In the thermostat we use 'proportional control' instead of simple on/off with hysteresis. This means that as the room approaches the set temperature we start to reduce the power output from the heaters. For instance if the target temperature is 20°C and the actual is 19.9°C, the power demand will be reduced to about 25%. If the temperature rises further it will be turned down more, if it falls it will be turned up more.
The result is completely a stable room temperature with no cycling at all.
All our thermostats designed to be fixed to a wall so that it they are never warmed by being handled. This is important to maintain precise room temperature.