The solution is kindergarten simple. Here's some facts though to ease your mind. Every square foot of sunlight carries almost 100 watts of heat. It's really about 88 watts but say 100. We'll subtract 12% (100-88) later. So imagine you have windows 24" x 36" . That's about 6 sq feet. And they can let in 100 watts per sq foot. how many watts of power = 600 watts. Here's where that makes sense: An electric floor heater is about 1500 watts. So imagine in the Summer turning on a floor heater and leaving it on for 1/2 hour then turn it off for 1/2 hour all during the day. That's about how much heat can come through that one window. Will putting something to keep heat out help. --- Next on the roof. Insulation doesn't keep heat in or out. Is slows down how long it takes to come. So it's going to come in no matter what unless. You block it. Imagine your roof is 20 feet x 40 feet and you have a 2 story house. That's a 1600 sq foot house. 800 on the top floor = 20 x 40 and 800 on the bottom. that's no matter. So 100 watts x 800 = 80,000 watts of heat It's going to get through. So will it help to shade it? Let's be real. If only 1/10th of that heat gets into the house that's still the same as 5 x 1500 watts of heat on all day in Summer. Would you turn on a heater in those examples above. Then don't let the heat come in How to do it cheap. Anything on the windows help. Foil is ok. it will last for years if you fit it to the window first and then glue it down on cardboard. Then you can place it into the window. Maybe even make it so it flips down , etc , for the view. Roof. Painting the roof white helps a lot compared to black roofs. Is the cost worth it? It's probably not compared to other choices like planting tress but a. Tress can ruin a roof. Chinese elm puts tiny leaves which keep water on a roof no matter what. That rots and so some tress avoid. b. Trees take time to grow but you can buy them 'fully' grown. And install them fully grown. b2) Palm ? They're not going to shade much but you just calculate what they'll shade , the cost, the cost per sq ft of shading and pick the tree with the lowest cost per sq foot of shading. c. Other roofing choices. Foam roofing is not hard to do yourself. You must read up on it. Practice. Then you can do it yourself. Pull a permit from the city. The equipment used is $15,000. You can sell it again for probably the same price if you clean it. That cleaning IS a part of reading how to maintain it. Cost for 2000 sq foot roof in materials is about $3000 for everything. Foam and the white latex coating that's reapplied every 10-15 years. As long as it's reapplied the foam should last a 'lifetime' (50 to 200 years) Without reading any of the posts there's are other ideas probably. Have a flat roof? here's an idea. Put up trees on the roof. Be sure to have a registered architect or structural engineer. But you could have a garden on the roof shading within a few weeks. put a lot of trees in containers and you could make some money selling them as they got too big. And birds lvoe it if there's grass and wild plants. it's a real viable 'way to do business' now a days in old and new construction. KEYWORDS To search Coolroofs Green roofs Attic insulation. It's easy and cheap. If you can put it under the actual roof rather than on top of the attic 'floor' it will do more for the amount. In fact that under the actual roof is an ideal place to practice when you buy the foam machine. Again you must read and study before you do it. But it really is 'stupid simple' You can foam the under roof for $2000 and put an r-8 or r-12 where it will do a lot of good. Cost is about $1500 for 2000 sq feet. You can't rent the foam equipment from my research but buying it is not a bad choice. It's simple well designed equipment nearly identical to airless spray paint sprayer. do both. under actual roof and top of attic floor. THere's no reason not to. Here's an FYI. Making your own insulation is 'easy' . 5 layers (about) of paper, foil, paper, foil, etc is exactly what was used in the commercial building trade for under the roof insulation. The paper can be from newspaper end rolls. Fireproofing it can be done with a couple of cheap, safe to use, easy to buy chemicals. Read up by reading about fireproofing for theaters and stage productions. If you have a community theater ask the director or stage production manager where they buy fireproofing liquids. Or make your own as was done for hundreds of years. To save money always. Go to a Chinese bulk product site. Look up the price they sell a TON of something for. Then look at what you pay. You'll soon figure out a decent multiple, say 10x , their price and then never pay more than that. in the case of fireproofing sodium silicate also called 'water glass' is $250 / ton or 10c / lb. Buy 50 lbs for $10 and you've got yourself a deal. Mix it with water, spray it on , let it dry and try to burn the paper or cloth. It won't burn. Ok that's my dump. Enjoy and keep it cool. Putting up a few solar panels to heat water will keep heat off that part of the roof. Just a thought.

antss, I really appreciate your expertise. I just wanted to contribute in a "thinking out loud" manner. Some of this 'common sense' is based on day to day experience. I've worked in a room that got terribly hot,... till I opened a stairway door, allowing a natural draft for the hot air... A friend of mine just moved in the same building to another apartment that had an extra corner room with windows and remarked how much cooler it was with the extra ventilation. The idea being to create a natural chimney effect. I assumed the heat would accumulate from people checking on the food, opening and closing the oven door, and just the mass of humanity that can warm up any room. Even in a little coffee house concert space it can get warm very fast unless you can open some doors and get a draft going. Since warm air rises, blowing it out (and some of those panasonic ceiling fans blow 400+ cfm, I thought it would help to get rid of the stale warm air that accumulates at the ceiling, and the make-up air(very important), I assumed would just come from an open kitchen plan, since most newer kitchens are not sealed off. Maybe they could have floor vents and bring the air up from under the house. I'm not designing anything, just offering a suggestion. Finally, I studied passive energy systems in college, and alternative energy. Decades ago, I lived in a windmill powered house with passive solar heat collectors. Much later I learned the benefit of "swamp coolers" in the SouthWest. I'm certainly no expert, just neighborly. And I don't mind it if you say I'm full of hot air.

light colored blinds, reflective blinds, insulated curtians.. still allow heat into the space between the window and the blind. keeping the heat out..shutters, low e. solar screens are better choices. many choices are dependent on personal situation and will always vary. Plantings in the yard can have up to a 30% reduction on cooling costs..again keeping the heat out of the house. the bananna trees in my front yard keep full sun from the front of my house starting in mid June. makes a difference in cooling the west facing front. please note that I am in a 9 month cooling climate. I do get some wicked north winds in the winter and have plantings of evergreens to make a wind block to help divert north winds from my home. there are lots of choices, you just have to find what works for you. some choices can be combined, others are counter productive.

@rockbird - Whatever you choose, get a few bids as I found significant price variation with different installers. The first 3M installer quoted me $3500 for film that was functionally equivalent to Avery Dennison which quoted me $1800. There was a climate control 3M that was $5400 from the first 3M installer. I had my designer get a quote from another 3M installer and the apples to apples bid from the second 3M installed was $2400 versus $1800 for Avery for what appeared to be the same technology. Both brands had various options available but I wanted something relatively simple - I wanted to block the destructive UV rays without having to have shades drawn constantly since I have a bank of windows with a view so there is always light but since it's an Eastern exposure, I don't have the relentless sun of a Western exposure. I didn't want something extremely dark nor did I want anything with a mirror finish on the exterior since I wasn't using these for privacy or really for climate control. The Avery Dennison installer said that the film I chose would have a slight impact on climate control but the main benefit is UV protection for furniture and floors. When they come out, they have cards with the film and you hold it up to the window to get a sense of how dark the windows will appear with each possibility.