Fans, power supplies and heat

[TomjNorthIdaho]

I recently received and installed some Netonix WS-26-400-IDC switches ( + or - 48 volts ).

They work well.

I had one on my desk and I was planning to keep it there , but the noise from the fans was more than I could handle.
The fans are constantly off then on then off. This got me to thinking ...
What is creating the bulk of the heat ?
Is the 48 to 24-volt and other internal voltage regulators linear or switching power supplies ?
Switching power supplies are typically more expensive but they produce far less heat than a linier power supply.
With most linier power supplies running with a 48 volt input , supporting an output load of 24 Volts at 1-amp ( 24 Watts ) means the linier power supply would be also be generating about 24 Watts in additional heat. Like a variable resistor, dropping 48 volts to supply a 24-Volt 1-Amp load results in the resistor creating heat. Is this why the 3 fans are in the Netonix ?
Would it be recommended to order some spare fans for replacement ( MTBF for the fans ) ?

North Idaho Tom Jones