If you have a cost reduction to all spells. so they are all 1 energy cost less. does that apply to flow? and does that apply to repeat?

Yes to both — a general cost reduction ("spells you play cost 1 less") applies to the total cost of the spell, and both Flow and Repeat costs are part of that total.

• Repeat: Repeat is an optional additional cost added to the total during cost determination, so your discount reduces it like any other part of the cost (Rule 356.2/356.4; FAQ #203, #8444).
• Flow: Flow is an alternate cost that replaces the base cost (Rule 829.1.c.1, 356.1.a). The total cost is still worked out normally after that replacement, so your discount applies to the Flow cost when you play the spell from your trash.

Two caveats: if your reduction only hits Energy costs and the Flow cost is a non-resource cost (e.g., "recycle a card"), it only reduces the Energy portion; and Energy/Power can't be reduced below 0 (Rule 356.6). Also, cards that check a spell's printed cost (like Defy) still see the printed cost, not the Flow/Repeat-modified total.