I have an almost 400sq ft master bedroom including master bath in a two bedroom, 1500 sq ft house. I have a three person jetted tub, a five foot shower with seat, a 55" single vanity. and a separate wc. It's big enough so I can have my dresser in the bathroom containing my underwear/basic wear. So when I wake up in the morning, I can go take my shower, get out of the shower, dry off and put on my basics. Turn around, blow dry my hair, put on my make up. All without ever having to turn on a light in the bedroom and without disturbing my husband who probably is still asleep. I spend at least 25 minutes every morning in my bathroom. One of my must haves during the design was ample space for my hair dryer, brushes and straightener. I want to be able to dry my hair while having my straightener turned on and heating up and I need a dedicated spot for that. At night, my 3 year old can comfortable splash in the tub, recreating a scene from godzilla with dinosaurs and boats while I relax in my recliner and whatch tv, while also keeping an eye on the kiddo because I do not have a door to my bathroom. After the kiddo is in bed, if I want to I can take a nice long soak while watching House Hunters. My master bath is massive in relation to the size of my house, but you know what? So what. It's not "fantasy living". I don't have to live with a child bothering me or knocking on the door, I'm not wasting any space. I spend a lot of time in my bathroom and I enjoy every minute of it. I'm not wasting any space. I don't have marble tile, I have soft, non slip luxury vinyl plank. I have a regular, plain old shower instead of a custom tiled shower. We only have one child. We don't entertain. We don't have a million overnight guests. If I had build 3 bedrooms, I would have one completely empty room that would never get used for anything except maybe some boxes. I don't even have furniture for a third bedroom. But the resale value!!! Who cares? I am not selling. Instead I built a massively oversize bedroom for the one child. If he wants sleepovers, he'll have plenty of room for all of his friends without having to break out an air mattress in the living room. And he can keep all of his toys in his room. I hate toys in the living room. Everyone advised us on this kid friendly feature and that kid friendly feature. Uhm...he's only 3 for one year of his life. So no. I'm not going with a Mickey Mouse light fixture and miniature urinal, things that were recommended to us in all seriousness during our build. Moral of the story. Make your bathroom any damn size you want. It's your bathroom.

In Manual J (the process for a load calculation), there are design temperatures that the system is "designed" around. In other words, in your climate, the design temperature may be 95-100 degrees in the summer. If your system is cycling on and off when it is this hot out, chances are you have more capacity than you need, and during milder weather, you have a lot more capacity than you need. A properly sized system will run just about constantly when it is extremely hot in the summer. So it sounds like the metal return ductwork comes from behind the furnace and enters below the furnace via a plenum box. By this info it seems like depth is not the physical constraint in this closet, but width is. Trane has an 80k btu furnace (80% efficient) that is 17.5" wide. It has a 3 ton blower, but it is variable speed and has a maximum airflow setting to support a 3.5 ton system with no problem. In fact, the factory setting is for a 3.5 ton system. Here is a system that I found from Trane that may work in your scenario: Furnace: TUD080R9V3 Coil: 4TXCB042BC3 A/C: 4TTR5042E1 The problem with this system is that its output when using a Trane coil (rather than a mismatched 3rd party coil) is rather low (output in btu/h) for a 3.5 ton system, at 37,800 (just a couple thousand btu's more than what a typical 3 ton would put out). A 3.5 ton system will generally put out 42,000 btu/h. This is just based on what the matchup yields. The 80k furnace with a 4 ton blower does much better in terms of capacity output, but it is also 21.5" wide. And lastly, the system unfortunately would not qualify for the federal tax credit. Putting the system in the attic does look like a very feasible option. It will indeed involve more work, running the gas line up there and also modifying the ductwork to connect to the furnace up there. So you can expect a price increase for an attic installation.

I would be hesitant to give up room in my bath area. If you shrink it to 7 x 5 you'll be limited in the size tub/shower you can use and I'd think you'd want the largest you could put in there since this is the MBR. As the other poster mentioned, moving all the plumbing will quickly add up, and moving a toilet is usually the last thing you want to do. Whether you have a slab or crawlspace under your home will be the determining factor. I've included a drawing of how I'd probably do the area. Our last home was similar to yours and limited in closet area, so DH used the spare bedroom and hall bath as his dressing area. I would take the small closet space in your BR and add it to the hall bath closet.......then one of you can use it as your personal closet. If you don't need a double sink, the other option would be to reverse the closet/sink layout I've drawn That would then give you more closet space in the BR but you'd have only one sink. The double sink wall shouldn't need to be there for privacy.......isn't there a door at the entrance to your BR? If you really wanted to get carried away with a remodel........and the hall bath isn't needed by others........you could absorb that bathroom into your plans and make a large bedroom/bath suite! :)

I would opt for bigger bath and one shared closet. Would overall be less cramped for space. If you do the closet with a wall closet system with various drawers and hangers there is more than ample space for you both. If not, then you have too many clothes. In my closet I have 3 drawers and a hanger above those in multiple areas, then I have hangers for long clothes, and we have corner shelving and shelves for storage on top. Lots of space. Shoe rack on the floor under the long clothes.