I too have no connection to Hass Mfg other than being a satisfied customer...

When I designed and built my current darkroom I was told by someone that I should "give up something else in order to get one of these" units. It was the best darkroom advice I've ever received. I subsequently purchased and installed one of the Intellifaucet K250 models and I have never regretted it. Rock solid water temperature control down to a tenth of a degree (well 2/10ths, actually) is downright spooky. This thing is so good that in my frequently below 68F/20C ambient room temperatures I will often set the unit to supply water at, say, 68.3F/20.2C in order to counteract the loss of tempered water heat to the air. And it works absolutely perfectly and repeatably every time. As I said - spooky.

Before investing (and while constructing) I did perform a twice-monthly cold water line check for one full year. I wanted to make certain my water temps were within a range that would make the investment worthwhile in terms of how often I could use the unit. As it turned out, my lowest temp was 43F/06C in February and my highest was 67F/19C in August. And testing showed the low-flow option to work perfectly while supplying 68F even at the peak 67F August mark.