Hi found this on eBay cheap and easy fit and wire in just have to fab a unit to hold in front of fan etc to blow the hit air to where its needed I hope this helps
12V/24V 150W/200W PTC Heating Element Thermostatic Electric Heater
DESCRIPTION:
input voltage: 12V/24V AC
Blowing surface temperature: 70-100℃; Dry surface :200 ℃
power: 150W/200W
heat material: PTC Thermistor
heat methods: heat conduction
lead wire: high temperature line
Size: 86*21*15mm
Main application :Air conditioning units, air curtain machine, QuShiJi, drying machine, dryer, heater, cars, etc. Need to provide warm air device.
specialty
1. Heat up quickly, when fan failure can control temperature, long service life
2. Don't burn, safe and reliable, not red, the halogen-light PTC heating
notice: Surface not insulation
Package include:
1 x PTC heating element heater
2 x cables