assistance with temp comtrol project plzzzzz.

Using Arduino Project Guidance
4

trinislick:
what exactly do you mean by software pwm?

Calculate percent heat needed: 0 to 100
Turn on relay.
delay PWM period * percent heat needed
Turn off relay.
delay PWM period * (100 - percent heat needed)

I'd use a PWM period between 6 and 60 seconds.