Here in Colorado, where the relative humidity is very low, though the temperature is often quite high, I use an evaporative cooler to keep the temperature inside the house reasonable.

I'm interested in finding either (a) an integrated setback thermostat that uses a thermal sensor pair, one to sense outdoor temperature, and one to sense indoor temperature, in order to determine when to engage the evaporative cooler, when to use only the blower, i.e. when it's sufficiently cooler outside, as at night, to warrant circulating outside air, and when to turn on the pump and water supply, or (b) one that, at least, controls the water supply as well as the power to the pump, based on whether there's sufficient termperature difference to warrant using the blower alone. Further, it would be really good if the thermostat in (a) above had a clock/calendar to ensure that it doesn't oscillate between using the cooler and using the furnace, as it might in the early spring and late autumn.

Presently, I'm considering using a sprinkler-system valve to control the water flow, based on whether the pump with is running, but I'm not sure it wouldn't be smarter to find a commercial product that does what I want, but I don't want to buy and install something, only to have to "rube" something to complete the function. If that becomes the case, I'd rather simply build the whole thing myself and be done with it.

What I have in mind is a simple MCU with a couple of temp sensors, a few triacs, an LCD to show what's purportedly going on, and a keypad. Anyone who's ever tried to implement a relatively seemingly straightforward function such as this knows that, first of all, the devil's in the details, and (b) it's never as simple as it looks. That's why I'd rather buy than build.

Any suggestions?

RE