Inexpensive Ways To Insulate House With Brick Walls?

Hang heavy tapestries on the walls and heavy carpets on the floors (like they did in medieval european castles).
I am also thinking that you could plant vegetation that is seasonal on the experior of the building. - it will be there when you need it and dormant otherwise.
Another suggestion is to install wall panels inside the rooms and put some kind of insulation between the wall and the panels.
You've probably thought of all these things already.

I wish you good luck.

We just put in some shade screens on the sunny side of the house. It sure helped. The heat still radiates through the window, but to a much reduced extent. My Dh measured and then ordered them online. They were delivered to our house. If you are not good at measuring, don't do it! Have a company come out. 6 large screens cost some $450 and you wouldn't want to have the dimensons off. They snap into place via a 'lip' that is on the exterior of our window. However, they will need to be screwed into the window frame place because we get high winds. If we did not have the 'lip', we'd have screwed them into the existing window screen frame.

I ordered them from www.qualitywindowscreen.com. Got the 80 something denier Phifer Suntex because the 90 would make the room too dark. Chose dark brown, because the lighter colors might show dirt. Felt a big difference in the climate of the room the first day the screens were installed.
Yes, the light that enters the room is 'odd' - and we have to keep the house lights on in the room because it's too dark - but it's still a lot cooler than it was. Burning lightbulbs is less expensive than airconditioning the whole house just because the kitchen is too hot and the ceiling fan isn't enough.

If cookwie would change her light bulbs to the energy efficient , curly type light bulbs, she will find that they do not add the heat of the old light bulbs, and saves electric. I finally talked my neighbor into changing out to those kind of bulbs - he couldn't believe how much he is saving in his electric bill now.

and his AC doesn't have to work so hard trying to cool down the light bulb heat as well as the regular heat. But you can't use just 1 bulb and tell the difference - you need to replace them all.