Can the 5E abjurer wizard recover temp hp on his arcane ward any time it is below max or only when it reaches 0?

Question

On p115 of the PHB under Arcane Ward there are a few facts that I think are clear:

• The ward is created by the first abjuration spell you cast in a day
• It has a max hp of level × 2 + int modifier.
• The ward does not absorb damage once it reaches 0 hp, but it remains until you take a long rest
• The ward can be recharged by casting abjuration spells, at a rate of 2 x spell level worth of hp 3.

However, the way they wrote the paragraph about recharging seems unclear to me. Can you recharge the ward whenever it is below max hp or only when it is at 0? My understanding of temporary hp would say it is the latter, but the writing on this ability infers the former.

An example.

If I were a level 10 abjurer with 20 int and cast Mage Armor, it would give the ward 25 hp. If I took 30 damage from an enemy, the ward would absorb 25 damage, leaving it at 0, and I would take the remaining 5 damage. If I cast Stoneskin (level 4 abjuration) the ward would be recharged with 8 hp. If I then cast Planar Binding (level 5 abjuration) which would be correct?

1. The ward remain at 8 hp
2. The ward would recharge an additional 10 hp to a total of 18 hp

Answer 1

I agree that the part about recharging is a bit ambiguous, because it's part of a two-sentence paragraph:

While the ward has 0 hit points, it can't absorb damage, but its magic remains. Whenever you cast an abjuration spell of 1st level or higher, the ward regains a number of hit points equal to twice the level of the spell.

If these were written in the other order, I don't think there'd be any potential for confusion, but this way, I can see someone reading the second sentence as conditional on the first. But, I don't think it's meant to be: if that were the case, the second sentence should be more clear about that.

So, I'd read it as your two spells (4th level and 5th level) recharging the ward to 18hp. And, this is also kind of sloppily worded, but presumably the ward's initial hit points are also the maximum — you can't "recharge" beyond that.

This reading is confirmed as the design intent in a tweet by co-designer Jeremy Crawford — thanks to wax_eagle for checking.

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Note that the ward does not mention temporary hit points. It is a stand-alone rule, and it should be read just on what it says. Even if the ward acts similarly to having temporary HP in some ways, it doesn't say that they are, so they aren't — and can work differently in some of the details. (And, crucially, you might have both the ward and temporary hit points.)

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For what it's worth, this does seem pretty awesome: a 10th level barbarian with a 20 con has 125 hit points. A level 10 abjurer with a 16 con has 72, and a 25 hp buffer — and if she uses all of her spell slots casting abjuration spells, that can recharge up to 82, for an effective total of 179. If one of those spells is Stoneskin, she has the same resistance to normal weapon damage as the ranging barbarian, although probably not as high an AC without making a lot of the castings Shield.

On the other hand, a 10th-level Moon Druid (say, around 83 hp) can shift into Ankylosaurus form twice between short rests, giving what's effectively two 68hp buffers and also you are a dinosaur. I expect once we get into Deep 5e Optimization Territory, there will be plenty of other things which outstrip the arcane ward.