Whenever I stay in a new hotel, I’m always intrigued and annoyed by the design of the bathroom appliances. Inevitably, the sink and shower have some weird design that makes it impossible to guess where cold water ends and hot water begins. In some cases, the knobs or handles just need to be turned a little bit further than what I’m used to. But in other scenarios, the entire spatial relationship is different, e.g. the shower lever only goes from two o’clock to five o’clock, rather than moving all the way around the dial.

In each of these cases, the unfamiliar interface makes the first interaction more complicated and stressful. It could even be dangerous if someone expects the faucet to behave one way, and ends up with scalding hot water as a result. While I doubt that appliance designers will agree on a standard user interface for sinks and showers, there is one simple thing they can do: include a built-in thermometer in their products.

I’m not talking about anything complicated. Just carve out a little area where the water comes out of the faucet, and insert a regular thermometer to show the water temperature. Ideally, the thermometer would also include clear labeling to delineate which temperature range is safe, versus the point that hot water becomes a burn hazard. Since a simple thermometer doesn’t even require a power source, it should be relatively straightforward to integrate this feature into future sink and shower designs.

In hotels, restaurants and similar venues, every first-time customer is forced to figure out the bathroom appliances on their own. There’s always the risk that the customer will burn themself and avoid that business in the future, or even pursue legal action. For these types of venues, a sink or shower with a built-in thermometer should command a premium over regular models. I’d love to see an appliance company give it a try, since the value of this feature is significant for customers and venue owners alike.