While I’m sure there’s some evidence of candle clocks being used as alarms and obviously plenty of proof of candle clocks existing. I don’t think they were common or super popular. This article sort of frames them as THE predecessor to electric clocks, which is not accurate. Sun dials, tower clocks and half a dozen other types of clocks were used more frequently than candle clocks.

Also, the idea of an candle alarm is sort of silly.

1. you’re wasting your light source while you sleep (as someone else mentioned)

2. FIRE - there were tons of candle holders and other devices created to extinguish candles if they were accidentally left lit. People generally didn’t want to have candles lit after they fell asleep because it’s a fire hazard.

3. Lastly, I think at least of the devices described in the article were used to show how much time the candle had left. Like a fuel gauge.

The devices described in the article seem to be legit and like I said, I’m sure candle clocks and maybe candle alarm clocks were used, but they were not super common.

Sun dials had some impact on the general population, but until the invention of tower clocks (which were often accompanied by cannons or bells) to mark the start of the day), the vast majority of people did not think of time in the way we do now. In fact, lots of people complained about clocks being a pain in the butt.

Source: several horology books, but most recently “About Time: A history of civilization in 12 clocks” by David Rooney.