My quilting room is 17 x 20 and I really need more room. My design wall is from floor to ceiling and 88 inches wide! Bought 5 yards white flannel when on sale for $2.50 ydand just stapled it to the drywall, two 44 inch strips, has worked great for over two years now. I don't know if I'd be able to make the quilts I do if not for that!
Congrats on getting your own space, you will love it!

I'd go 20 x 25. and someone suggested inside wall cabinets, which is a good idea. Just make sure you have ton's of window views too. I'd place the sewing room facing towards the back yard garden. Yep, make yourself a "viewing garden". and don't forget a design wall space.
Lucky Girl you are.

Mine is 24x26 and full! I do have a long arm which takes up a lot of space, also lots of "stuff"

When having an electrician working on our new home I mentioned that I did not want my iron browning out have the lights in the house. He suggested having a special 20 amp circuit for the iron -- he said they really draw a lot of power when they cycle on. My old room was 8x9 -- my new one will be a bit bigger but not much, but it will have a closet.

My sewing room is 250 sq. ft. It's rectangular shaped. It holds everything I need and I have room to move around. The pictures are taken from each end (front to back, back to front). It's a room built next to the garage with door access to the back yard and door access to the garage. It is heated and air conditioned and has windows at both ends so I get lots of natural light.

Mine is 18x30 I have HQ16, 2 machines,cutting table,large ironing table, design wall and lots of storage and closet.

My sewing room is about 15 x 17 and isn't big enough. I don't have room for a long arm. I have cupboards on 2 of the 17 foot walls and that makes the 15 foot wall about 11 feet. The advantage I have is there are 3 closets in the room but they are used for storage of things like suitcases and my husbands clothes since the closet in our room is full of my clothes. lol
My humble opinion is the larger your space is the more "stuff" you accumulate. You should probably go as large as you can afford. My dream room is probably as large as a small warehouse, and I would probably out grow it as soon as I built it.
Sue

My current space is 14 1/2 x 24 and it is much too narrow for my needs. I do own a longarm, so as one boardmember mentioned, if that is a future consideration, plan for it now. I moved from a smaller square room to my present area and found the square room to be more functional even though the square footage was a bit less. Definitely plan it out on graph paper taking into account how much room you need behind your chairs for maneuverability, etc. I have a 6x8 foot closet off the end for fabric storage cabinets, so that is not even a factor in the overall lack of "spaciousness" in the room. Bottom line, for me, I would have the same square footage, but a square room (I used to have a large workstation/cutting table in the very center and that is not an option now) or a wider room. For some dang reason, space seems to disappear once you get all of your "stuff" in there...

Bigger that a 2 car garage would be the size for me.