>Peltiers are less efficient when PWM'd than when driven by a DC current
huh. hadn't thought of this before but it makes sense from the datasheets. in other words: add an LC filter between your PWM driver and your Peltier. or use a proper SMPS
https://www.meerstetter.ch/customer-center/compendium/71-peltier-element-efficiency
another nice thing is that Peltiers are resistive loads, so they're really easy to control