I visited my grandmother in Kansas, when she was 75, she had stopped using the upstairs of her house. Not sure when she did it, but she shut it off and it was only used for guests. One reason was to save energy because of heat in the winter and air conditioning in the summer were expensive - she moved what she needed down stairs she was 93 when she passed away. When my mom reached 72, she did the same thing - she lived in Western Washington, and lived to be 80. Even though they did have a lift installed on the stairs because my dad had heart surgery and he always wanted access to the upstairs - they had a basement my mom didn't ever go into for 8 years. My aunt has the Kansas house now and the upstairs only gets used for guests. The stairway is way too small for a lift.
So I would suggest if you do put the sewing machine upstairs - I would give it, its own heating and air conditioning units so you only run it when you are in it and put in a lift up the stairs before you need it.