Without some more details, I would say the presumption is just that you're wrong. The amounts healed by both of these spells are documented as are the casttimes. At lvl 70 (which is I assume where you are, based on the spec you linked to) you get something like

GHeal: 2635 average heal (rank 7), 2.5 second cast time (since you have 5/5 Divine Fury)
Heal per cast time: 2635/2.5 = 1054
FHeal: 1190 average heal (rank 9), 1.5 second cast time
Heal per cast time: 1190/1.5 = 793

In terms of heals per mana, glyphed FH is comparable to GHeal though not quite as good; if your GHeal tends to overheal more then FHeal may well have better mana efficiency, at least for you, but looking just at the baseline values this isn't the case either. Basically, (glyphed) Flash Heal costs just a little more than half as much as GHeal while healing a little less than half as much.

Adding spellpower to the above changes nothing. With or without Empowered Healing, Greater Heal appears to have exactly twice the spellpower coefficient of Flash Heal. If you increased spellpower indefinitely, you would see Greater Heal maintain a healing-per-second advantage of 1.2:1 (slightly less than the 1.3:1 advantage it has at 0 spellpower). The healing per mana would end up being very similar, however.

Anyway, if you have a combat log that shows some results you think are unusual (for example, that show Flash Heal and Greater Heal giving different results than what Thottbot show for those spells) then please link to it if you can.

No. Empowered Healing does not change the way these spells scale with respect to each other (though it does help them both in comparison to other spells). The ratio of coefficients is 2:1 with or without Empowered Healing. If anything, since the HPS of GHeal starts around 1.3x that of FHeal (at 70) or 1.26x (at 80) while asymptotically approaching 1.2x as spellpower goes to infinity, the increased spellpower that Empowered Healing gives will make FH look ever so slightly better.

Also, Greater Heals is more likely to proc Serendipity, which makes Greater Heals a bit more mana efficient than Flash Heals.

At level 80 with 5/5 empowered healing, my Flash Heal do pretty much 50% of the healing of my Greater Heals. I do think with the Glyph of Flash heal, the mana efficiency is similar.

I dunno, there are more factors than just Serendipity (which is to some extent under the priest's control). Flash Heal has an equal chance as Greater Heal to proc IHC, Surge of Light, or trinkets like the Soul Preserver or the Majestic Dragon Figurine, so in some ways the HPM may tip in Flash Heal's favor. I'm still having trouble modeling this one myself.

I know it's not a precise mathematical model of the situation, but for all intents and purposes it seems like the HPM is similar enough that you can mostly ignore that factor and just use the heal that seems most appropriate for the situation. Obviously, if you're healing a 10k deficit and need to top it off as soon as possible, Flash Heal isn't going to be your answer. But for smaller chunks, I don't see any reason to use Greater Heal simply because of a higher theoretical mana efficiency. Sometimes a little bit of logic and situational awareness is more important than hard mathematics.

That being said, it would be nice to have a good model of the situation for theorycrafting purposes.

Flash Heal will have more chances to proc those things for both mana and time, because you will cast more of it, and in smaller periods of time.

Seems people still doubt Divine Hymn, It can easily do over 30k healing, and seems to smart target. Don't think I've used it for CC once, but I use it in a lot of the later encounters as an incredibly efficient aoe hot.

Do the level 80 combat ratings provided here: Game Mechanics - WotlkWiki - Wrath of the Lich King Information still stand as a guideline or has it changed since that build?

How does Prayer of Mending works with regards to self damaging capacities ?

To be precise, I know I have used Shadow Word : Death to make sure a PoM buff procs on me, but I wonder about other abilities.

Warlock : connexion (my experience at 70 is that it does not make PoM jump, but I'd rather have confirmation)
Paladin : seal of martyr (I've never cared at level 70, being alliance, but now I'd like to know)
blood Death knight : Hysteria
Warrior : health cost of Bloodrage

I've never seen PoM being triggered by self damage abilities other than Shadow Word: Death. SW seems to be different because the damage doesn't seem to be counted as done by the Priest.

But that AOE hot is making your enemies take 40% less damage for at least 3 seconds. I have not found many fights where this is a good tradeoff...

I don't know if bosses actually get the benefit since they are immune to the incapacitate effect. I have been liberally been using it in boss fights up to now.

"Incapacitated enemies take 40% less damage while incapacitated and for 3 sec after the incapacitation ends."

Of course tooltip and reality have been known to differ before.

However, in any normal case it does not matter if the boss takes 40 % less damage for 3 seconds anyway, since no enrage timer so far in WotlK is so tight.

Simple Question: How should a Holy Priest best heal on Sapphiron?

I did the 10 man version last Saturday and we required the prot pally (off tank) to respec healing because we needed 3 healers. Eventually we should be doing all of Naxx (10) with 2 healers. So we had 2 holy pallies (one on tank full time, one throwing heals around, and me healing the raid). I specced for 7 sec PoM, which was thrown up every time it was off cooldown pretty much. I tried to heal the other group more so that I could PoH my group. I didn't use CoH nearly as much as I probably should have because of movement, and this is my first major issue: How do you move to avoid the blizzard and still stay within range of eachother for PoH / CoH? My other issue was mana. I know this will be largely helped through gear, but it seemed like I spent 95% of the fight I5SR (which sucks, since I love spirit). I did get an innervate and used a shadowfiend (shielded) and a Runic Mana Potion. So the second question: How do I maximize regen? Also, out of curiousity is any class a better raid healer for this fight?

Through reading this forum, I have a few ideas (such as using Divine Hymn effectively, and using a glyphed Holy Nova while hiding behind ice blocks), but I welcome other ideas.

For Sapphiron 10 man it makes an amazing difference to just have the ranged stay close and use Mending until phase 2, then start using CoH and the like. Mending took care of the majority of the aura healing on the ranged for me and allowed me to focus on the melee and curse targets.

I am finding that with trying to concentrate on health bars and all the combat text flying around the screen, I am sometimes missing when Surge of Light, Clearcasting or Holy Concentration 2 procs. Are there any mods that give you an audio alert when these proc? I'm missing them at times and I'm still leveling up and healing 5 mans.

I don't want to think about watching 25 health bars, my own state of being (move out of the goo) and also visually attending to these three. Yet, the procs from the three talents seem an important component of mana management. Can anyone recommend a good mod that would sound different tones when these three talents proc?

The addon ThankGod had this functionality, but I believe development on it has been discontinued. According to Curse, the last release was on 10/16/2008 for 2.4.

The addon EventAlert does have some limited sound file capability, but only plays the same sound for each buff.

Is it a bug or intended that Penance and instant spells aren't consuming the Borrowed Time buff? Should disc priests count on being able to use PW:S --> hasted Penance --> hasted GH/FH for burst healing? The CGD between Penance and GH/FH is also affected by haste... would it be better hps to slot in a PoM to take advantage of two hasted GCDs?

edit: Also, is the size of the bubble produced by Divine Aegis based on healing done (ala Ancestral Awakening), or total healing?

As far as I know it´s intended that only casted spells are hasted. The Buff itself says "25 % spell haste until next spell cast". While it might be a bit speculative I can only suspect that Penance in one way or another is counted as an instant since its mana cost is consumed at the start of the spell and Borrowed Time means a "casted" spell (read *a spell with cast time*).

Concerning Aegis: Its based on the total amount, regardless of overhealing.

I just switched from shaman to priest and I've been having the same issue. I've been using Power Auras -- Power Auras Classic - Addons - Curse

I couldn't get Thankgod to actually do anything. PowerAuras still works and is pretty awesome for that sort of thing, allowing for both a texture and a timer.

Since my Penance comsumes Borrowed Time I'd have to say that you're seeing a bug. All casting or channeled abilities should comsume it. There was a bug in Beta where one could use Inner Focus + Penance indefinitely. Perhaps that's still around in some fashion. Worth reporting if that happens to you.

I'm not sure where your "two hasted GCDs" come from. My instants don't consume Borrowed Time, so I'm not entirely convinced that they are actually hasted. And then you should really only get one hasted spell. But generally yes: PW:S into hasted Penance is good burst healing.

When I'm pressed for Mana in 5-mans (only because of bad gear I suppose) I heal like something like this: Greater Heal stop-casting until target has taken sufficient damage -> PW:S -> PoM (if there's any secondary damage) -> Penance -> Repeat

Between Penance and Greater Heal you'll get a few full mana regen seconds. At that point you can also slot in an Inner Focus Prayer of Healing/Greater Heal to extend the regen period.

Do Divine Hymn and Hymn of Hope channel faster with Borrowed Time?

Aegis works off total healing. Crits on full health targets cause Aegis. However Aegis is reduced by healing debuffs. As one would expect really.

I haven't seen a discussion of Guardian Spirit and its use in PvE encounters and was wondering how it was being used. It's a spell that lasts for 10 seconds with a 3 minute cooldown, so for most boss types of encounters you will use it once or twice. Without having played around with it yet, it seems like an oh shit button, which is better suited for PvP rather than PvE. Am I missing something? Have any of you been using this spell/talent extensively for PvE and if so can you share your insights with me? Is it used primarily on soft targets who have grabbed aggro? Is it used on hard targets during spikes? Do you find it indispensible or something that in theory is nice but in practice doesn't deliver?

My experience with Guardian Spirit thus far is that yes, it is an "Oh Shit" ability. And with latency, it is less than optimal in that role. When the tank is below 5k, I will immediately cast it. The key is to let your tank know so s/he doesn't use Last Stand or Shield Wall. You actually want the tank to consume the buff because it's a free 15k heal (on a decently geared tank). That way, next time there's a damage spike and you're low on mana you can use Shield Wall and get some regen. Alternately, you can immediately cast a Greater Heal after Guardian Spirit, knowing that heal is going to hit really hard.

My issue with the spell is, there are 3 times in the last two days I have cast this on the tank (starting cooldown) but the tank dies before it lands.

This spell can be amazing in certain situations where you know a big mean ability is coming, but I haven't found many of those in LK.