Well, night time and day time detection can be done in the programming with a light sensor. Thats easy....
What kind of lights are you controlling? how are they powered?
(VDC, 115VAC, 240VAC, ect.)
(1)You need to know how much current each light will draw when it is on.
(2)Also need to know how much current the Heater Draws when on, and how it is powered.
(3)Do those lights Dim with Pulse-Width-Modulation or Variable Voltages? same ? applies to heater as well...
Im kinda the opposite of you, I just started with programming, but i've done electronics all my life lol.
I just need to know the MAX and average current values and voltages and such before looking into to how to go about this.