Renewal heals for like 1k HP. All you need to do now is learn how to bait :)

All calculations below assume you neither lose nor gain HP from other sources during the 2 seconds the tether holds.

Without items and masteries, Renewal heals for 20% missing health. Example:

• you have 500 of 2000 HP, i.e. 1500 missing HP
• Renewal instantly heals for 300 HP
• upon rooting your target (or its death) you heal for another 240 HP
• total heal amount is 540 HP

Adding the masteries Windspeaker's Blessing and Runic Armor :

• initial heal increases to 356 HP
• total heal amount increases to 628 HP

Suppose mid game and you now have both Spirit Visage and Redemption:

• initial heal 527 HP
• total heal 868 HP

Late game, full build and 500 of 3249 HP:

• initial heal 1113 HP
• total heal 1776 HP

Suppose you are level 13 and you have 45% CDR through items and Intelligence .

• Focused Resolve cooldown is now at 6.6 seconds
• Mantra cooldown is now at 21.45 seconds
• Gathering Fire reduces Mantra cooldown by 3 seconds each time you damage a champion with an ability, i.e. upon fully casting Renewal, i.e. through all of its three ticks, Mantras cooldown drops another 9 seconds through Gathering Fire down to 12.45 seconds
• with one Inner Flame and two auto attacks you lower Mantras cooldown for another 6 seconds down to 6.45 seconds

You end up being able to cast Renewal every 7 seconds!