Surge protectors are often rated in the amount of Joules of energy they can absorb, so you're likely to see this information clearly advertised on the surge protector. (howtogeek.com)
Given a forcing in units of Joules per second, acting on a mass with a heat capacity in units of Kelvin per Joule, the result of integration over time will be temperature in Kelvin. (wattsupwiththat.com)
In the end I found the dresses at Joules, and they were ones that they could definitely wear again. (boho-weddings.com)