Ask the architect for a solution. I'm sure he/she understands the problem better than we could from that description.

We parted ways with the architect long ago over these types of issues. He could draw a pretty elevation but was hopeless on interior space planning. It's not so much that the space is really weird since it could be used as a regular 5 x 9 walk in closet but I would like to capture that 20" x 36" niche that's sitting there at the far right hand front side of the space.

Build in shelves and use it to store tubs of off season clothing, garment bags, or shoes.

Could you post a drawing of the space? That might help, I am having a hard time visualizing what you describe.

Put 18" deep shelves across the 20" width. Put hooks on the remaining 18" (both sides) to hold narrow items, like belts, ties, scarves. On the side next to the boxed section, put a valet rod. This is something that you pull out that can hold (temporarily) clothes back from the cleaners, the clothes you're going to wear the next day, the garment bag you're packing or unpacking, etc.

Here is a link that might be useful:

Thank you everyone. My son will be visiting with us tomorrow and if he has time I'll try to have him help me post a diagram of the space that will be more helpful in explaining my dilemma. I'm not good enough with computer skills to post one myself so I rely on the young folks for guidance.

You should warn him that if he makes a mistake you'll bad mouth him on an internet forum.

Thanks to those who are trying to figure out my explanations. DS is still out of town and not available for diagram help so I'll try again to explain. The original closet was 5' x 12' with a door centered in the long wall. The a/c miscalculation caused us to lose a chunk of closet in the right hand rear corner of the closet as you face into the closet from the doorway. That corner has been boxed out with drywall to enclose the ductwork that now runs through the closet and the boxed out section is 3'4" long extending along the 5' dimension of the closet and 3' long extending along the 12' dimension. This has left us with a niche in the right front of the closet the width of which is the remaining 20" of the 5' dimension and 3' deep. Hope this is making better sense now.

The first thing we did to try to compensate for the loss of space was to move the closet door to the left so it is now centered on the 9' long rear wall of the closet that had been 12' long before the boxing out was done. So what you could say is that we now have a 5' deep by 9' long rectangular closet with a door centered in the 9' length with a niche off to the far right front of the closet.

Thanks for your patience in reading through this and trying to decipher my meaning and if anyone could offer anymore suggestions on what I could do to make use of that niche space I would greatly appreciate the advice.

If I understand you correctly, you originally had a closet where you could have hanging space on the two short walls and one long wall, which would give you 18' of hanging space, assuming that you don't have double hanging space, drawers or any other stuff other than single clothes rods. That is, 3' hanging space on the two short walls and 12' hanging space on the long wall (alternatively, 5' hanging space on the two short walls and 8' hanging space on the long wall.)
Now, you can still have 3' of hanging space on one wall, 3'4" of hanging space on the boxed in side, 9' of space on the long wall of easily accessible hanging space, and 3' of not so accessible reach-in slightly narrow hanging space, for a total of 18'4" of hanging space, of which 3' would be of limited use.
Is there any way that the boxed in space could be made 4" narrower? If so, you really wouldn't lose any hanging space, because the niche would be wide enough to have reasonably reach-in hanging space.

So you want ideas on how to use the 20" wide, 36" deep 'nook'. It sounds like you're not losing much space, but now have an odd niche to fill. Think about items you want to store in your closet that don't hang, and see how best to store them. Let that be your guide.

1. Make 20" wide, 36" deep drawers in the bottom half, and either shelves, slanted shoe shelves or a very narrow section of hanging space for coats. Shelves would be very deep, but you could limit the depth by putting a backing on the shelf unit. Slanted Shoe shelves could be two rows deep.

2. Make shelves, the whole thing, and install roll-outs, like you would in a kitchen. That would give you access to the rear of the space.

Her's a site that you can use to figure out a closet layout that will make maximum use of your space.

I played around with what I think is your layout, and used their auto layout feature to fill the space. Here's what it did:
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Here is a link that might be useful: Easy Closets

Could you access that space and use it from any other room in the house? I am assuming you are in the framing stage at this point?

Thank you all so much. We're at the final stages and hope to get c.o. by the end of May. The framing was done months ago and the "box" around the ductwork can't done any smaller and it's not possible to access the niche from another room. I just haven't had the time to focus on this with all of the other decisions going at the same time---you now the Scarlett O'Hara routine of "I'll think about that tomorrow."

I'm a bit calmer about the awkward space now but when I first realized I couldn't do what I had planned for the closet I really did have one of my moments of despair over ever getting everything to work in this house. Anyway, suero has it almost exactly right with the diagram of the space except that the boxing is at the rear of the closet and the niche is at the door end. I guess I was fantasizing that I could build in (the carpenter actually) some 24" pull out trays behind a 12" deep sort of hinged swivel "secret door" panel of shoe shelves that would fill the space in front of the pull outs. Does that sound crazy, doable, or just doable but crazily expensive?

Doable, but crazy expensive...:) but if you can swing it budget wise that sounds great. Just keep in mind that when you put something in that space you are utilizing the space but may lose space on the wall to the right of the door so that you can access that space.

Me, I was thinking that space was probably just the right size to stash away one of those wheeled laundry basket thingies with the hanging bar at the top. Easy to gather dirty laundry then roll it to the laundry room and back to the closet again filled with nice clean clothes.

My 2nd option would probably be a stack of long, narrow, drawers for storing things like blue jeans. with deep shelves above that filled with those clear boxes full of shoes/sweaters or what have you. Just make sure you have good heavy duty slides on the drawers.

Option 3, and probably the least expensive, would be to put some 12 inch deep open shelves at the back of the niche for storing things that you don't access often (like x-mas decorations) and then put a hanging bar in front part of the niche and hang things like out-of-season clothing or formal wear. Taking such stuff out of the way once or twice a year to access the hidden shelves behind wouldn't be much of a hassle.

Here is a link that might be useful: wheeled laundry basket.

Thank you everyone for your help. I haven't made any decisions on what to do yet but now I have hope that I'll be able to get a closet I like not just one that I can tolerate. Bevangel, that wheeled laundry cart is totally awesome and I'm going to find someplace to use it even if it isn't in this closet. We are getting close to finishing up the house but I'm probably going to wait to do this closet but when it's done I'll learn to post pictures to show you how it all turned out. I hope I can figure out something really clever using all of your suggestions.