Best (cheap) way to do draping ceiling curtains?

Erin, Are the beams metal? Have you considered using material such as window shades are made of? What are the dimensions of your ceiling? How much of it do you want covered? Muslin is inexpensive, The drapery in the picture you posted is quite extensive and would probably cost a lot. Sometimes reed shades are inexpensive and would serve your purpose. We need to know how you can or want to fasten them and how much you want to cover.

You could use tension rods in the sections of the window frames to drape the material over. OR--you could install eye hooks and use rope or twine stretched across to drape the material on. Muslin IS inexpensive especially if you have any coupons for a store like JoAnn Fabrics. I do think you will still get the heat from the windows--even if you drape everything. The sun will still come beating through those windows and the material isn't going to stop the heat--it will just give you some filtered shade from the sun.

You could use eye hooks.

Sheets, especially on clearance or on sale provide lots of fabric to work with (plus they are hemmed). Drop cloth, too. My first thought was tension rods between the beams. Tension rods intended for bathrooms give you more width and are made for around moisture.

https://smile.amazon.com/ALLZONE-Tension-Curtain-Collapse-drilling/dp/B06VWLNK5S/ref=sr_1_13?s=home-garden&ie=UTF8&qid=1525967607&sr=1-13&keywords=shower+curtain+rods

Well Erin--I still think it would look "cool"! Cooler than the car window foil--but hey--not a bad suggestion! Anything to deflect the heat. Is there a way to put a small air conditioner in those windows? I can't see if they are double hung windows or not but you can pick up a small air conditioner for about 100.00. At least you could tolerate the room and use it. I would LOVE to have a sun porch!

Ok. This is a bit Out of the box, but...

Emergency foil “blankets”, which are 55” wide by 84” long, for about $1.50 each at Walmart and lots of places on the web. Light as a feather. Keep out the sun.

Even duck-taped together on the top side.

So, get some self-stick magnets for your framing (Joanne or Michaels)

and then stick some as well on the edges of your magic silver panels. Make the “panels” extra long, so you can use your command hooks and maybe some black cording, or even hem tape to do your draping.

I do think I might add some double stick tape to an edge of the cording so the panels don’t shift too much.

Aaahh! Good air conditioning to have. Very efficient! Good grief--I hope it doesn't get so hot in that room that the plastic game pieces would melt!!! I think you will be fine as long as the air is on. You can set it at a higher temp just to kept it comfortable when you are using the room--like 78/80. I have a heat pump air conditioner--they are so efficient and don't add that much to your electric bill. I turn mine on and off depending on the temps--sometimes it will run for days. I only see about a 20 dollar increase in my fairly consistent summer electric bill. (winter--a whole different story!!)

I meant set the temp higher when you are NOT using the room.

great. Have fun with it

That picture you show as an example -they used tulle, doesn't get any cheaper than that. I had a large long skylight with direct sun. I picked up thermal curtains (in summer, on sale), cut them to fit and hemmed them with pell and an iron. Then stuck them up, 'draping' them over light inexpensive dowel rods.

I would do the rope/stringing holes method previously described BUT I would buy clearance-priced BLOCK OUT CURTAIN PANELS to block out the hot and harmful rays. If you can't get cheap (sale) block out shades in one color or panel, MIX EM UP! For the patio that would look SO festive!

I hope you let us see your finished project!

Susspend ropes acros or wires for curtains. Hang curtains over. If you make pocket seams where the wires or ropes are you can thread them through the curtain and that will secure them until you want to remove them.

I would think that ceiling fans would provide more cooling then curtains. If needed there are home made misting systems that could also work.