You've had a lot of good suggestions ... and not knowing all the variables of your situation, it's hard for us to know how to zero in on your solution.

I sew in a finished basement with cement floors. I do have carpet around my sewing area ... a nuisance for pins and thread, though warmer underfoot, and some padding when standing at the ironing board. Compromise!

For the heat rises, cold drops issue ... I turn the fan of my furnace on before I go downstairs and that helps to get the air moving, so I get more use of the heat!

If you can, position yourself near where the duct work brings the heat to you. If not, consider some renos to the ductwork to make it work better for you.

And I always keep a fleece vest handy to put on/off as needed!

When it comes to summer ... you'll love the coolness of your basement and will discover it's the BEST way to beat our Ontario heat and humidity! I get a lot of sewing done when it's just too hot to exist ... and as I go up the stairs, the wall of heat hits me!! :)

Make sure you get a electric ceramic heater. They are much safer.

I had several different space heaters , the one with the oil in the core work wonderfully. If its a sewing day .. I go down and turn it on about 45 minutes before. One thing I would not do with out... WOOL socks ... simple but its amazing how much warmer I am.

Ok I know this sounds crazy but I like to sew bare footed so these little piggy get cold. I have a heated welping pad under my machine. These are like heating pads that are use in dog kennals are in ferrin crates for pigs

They have those electric space heaters that are really nice and put out a lot of heat. They are also making them a lot safer than they used to. You can find a lot of different kinds at Lowes or Home Depot. Even Walmart handles them. Be sure to check the size space they heat on the box along with all of the diferent features. Hope you find somethig that will make your new sewing room extra cozy. Happy quilting!

I have a friend who swears by her "ceramic" electric heater. It's very small, maybe 10 x 10 x 10. She claims it's very energy efficient.

I have a portable heater.

Do you have a door on your sewing space? In our basement family room there is an opening, but no door to the stairs. In the winter we hang a heavy curtain over the door. That stops the heat from rising and limits some of the drafts.

The family room has two more doors and a window. We hang a heavy drape over the entire window wall in the winter. The door to the garage is not insulated, so we put extra weather stripping around it and a heavy drape on it too.

We have an oil filled radiator that we keep on low all the time and bump up when we are watching TV in there. The radiators are nice as they do not have a blower. There is no noise and no problem with patterns being blown around (I sew clothes too).

We use the plastic sheeting on our two bathroom windows during the colder weather. It works really well.

Someone else mentioned a fleece vest, I agree, keeping my back and neck warm makes a big difference.

If you don't need a lot, for some reason it seems to raise the temp a few degrees if you run a dehumidifier. I know lots of people use portable heaters and I have in the past as well. But my electrician friend REALLY doesn't like them and told me at least if I was going to use one not to run it on the highest setting. i've heard some good things about some newer ones that do run on electricity but it sounds more like the draw is more equal to a light bulb. Think there are some kind of quartz or ceramic parts that get heated up. I don't really know about them but have the impression that they are safer and also less expensive to run.

Bad draft where I sew. Have a small heater that is wonderful.

We converted half of our garage into a bedroom and added a window to make it "legal" but no heat run. Bought an "oil heater" and that sucker is great. Kicks out lots of heat. Check it out. Others are suggesting it too.