Plants shouldn't need "looking after" for a week's time.
If you had watered the plant the day of or the day before leaving, that would have sufficed for any watering the N.I.P. would have required.

Had the person continued watering while you were away, he would have needlessly given the plant too much water.
You, putting it near a heat vent, was the problem.
Plants.....all plants, do not appreciate their soil and leaves so abruptly affected by air currents that dry them out.

All you can do is give the plant a thorough....a very thorough watering making sure it drains and not leaving the plant sitting in such drainage more than 10 minutes or so.
If the roots still have life in them, they will see the needles get theirs.
Remove it from such air currents and give it the best sun you can.
Try to place it where it receives a western or southern exposure. If the needles do not recover in a reasonable time, then you might unroot it, see if there is any damage or dryness in the roots and give it a fresh potting soil.

N.I.P.'s do not respond well if they are allowed to dry out very long but a week's time is not such a time that it should be affected.

Well, I don't think it hurts anything to try, but I don't think it's likely to come back. Try keeping it in a cool (around 50-70F / 10-21C), humid, and bright (bright indirect light or filtered sun) place, or whatever you've got that's closest to that, and see how it goes, but it is probably too late. You should know in about a month whether it's still got some life left in it.

I think that if your tree is dead, you're the one who killed it. All you had to do before leaving was give it a little splash of water and move it away from the heat. You can try giving it a good soaking and moving it away from the register, but if all the needles are dry and crumbly, you're probably too late.

Even if it does survive, it will lose several of its lower branches. You should give it a good soaking, like Jeannie said, then not water again until it's mostly dry. How tall is the tree? Can you post a picture?

NIPs and conifers in general can be really slow to show damage, so it's entirely possible it's been dead for a few weeks and it's just NOW showing it.

Also, while they're not that drought tolerant, a week of hot air and no water probably isn't going to kill it. It'll start drooping, get dead needles, and some of the lower branches will die (and eventually drop off, but it takes awhile for them to actually brown up), but it's not likely the whole tree will die.

I love this judgey thing people are doing. It's not enough to answer the question and give a little extra information so somebody can learn how to care for the next one, people have to be sure to say you! You're the murderer! [dramatic prairie dog music] and pile on the guilt besides.

A rootbound NIP in a four-inch pot might very well have needed to be looked after during the course of a week; a "little splash of water" might or might not have been sufficient. An eight-foot tall plant in a 16-inch pot would be an entirely different story. Or maybe the plant in question was badly overpotted, or severely cramped.

"Near" a heat vent could mean directly on top of it, or it could mean a few feet away. NIP actually do like air circulation, they'd just rather it be cool, moist air instead of hot and dry.

Nowhere are we told how long this plant had been in the house to begin with, or how much water it had been used to receiving, or how often, or whether there are any signs of pests, or any number of other things. So come on. A little benefit of the doubt, maybe?

If nothing else, it's a plant. You kill one, you can buy another. There's really no point to trying to make anybody feel bad about the whole business, too. Crikey.

I hope I didn't give the impression that I'm being judgmental or anything. I was just saying that it's a bit hard to gauge exactly what killed it, or if it's even actually dead, because there's not a whole lot of information provided by the original poster. Pictures would be useful, probably.

I was just going off my own experience with mine and from what I've read elsewhere, where the tree starts dropping branches as a drought response when faced with underwatering. All of the needles going crispy at once just sounded odd to me.

There's also the possibility that, if this was a recently purchased plant, it was already well on the way out before it was even bought. I see a lot of dead NIPs in stores. Depending on the store, I see more dead NIPs than live ones. Just more speculation, though.

No, amccour, I was aiming more at "I think that if your tree is dead, you're the one who killed it. All you had to do before leaving was give it a little splash of water and move it away from the heat." and "Plants shouldn't need 'looking after' for a week's time." and "You, putting it near a heat vent, was the problem."

Any of these might be true, of course. But my point is just that taking the attitude that any moron would know not to put it by the heat, and anybody who wasn't a complete idiot would know to just water before they left, is not only not necessarily true (depending on the size, history, and potboundness of the plant), it's not helpful even if it is true. People aren't born knowing how to take care of plants, everybody kills some plants from time to time, and acting like plant care is this totally obvious thing that anybody should have figured out already is just going to discourage beginners from trying again.

This doesn't mean that I think jeannie7 or oklahoma tim are necessarily bad people; I'm just saying that I was a little offended on behalf of kestral jade, who hasn't done anything in this situation that everybody reading this hasn't done several times before too.

Being fairly new (and mainly a lurker) to this forum I was going to stay out of this one, but I just wanted to share something a very wise lady once told me. "You can't call yourself a gardener until you've killed a few plants." Many of my plants do very well in spite of me, some have died, even when I've done everything "right". If it dies, learn from it and move on.