rabbitgoo Window Privacy Film One Way Window Tint for Home, Removable Reflective Heat Sun Blocking Anti UV Glass Door Covering, Mirror Tinting Film House Office, 35.4 Inch X 9.8 Feet, Silver

We've had great luck this year with this product: https://www.amazon.com/dp/B0D5LRKP4Z on our old single pane windows, but people generally recommend using films like these with double/triple pane glass. They can heat up and stress the gaskets that seal the space between the panes, something it voids warranties. If you're interested in trying something like these, they're great for seasonal use and then they're easy to remove in the cooler months. You'd probably want to check with your window manufacturer though.

If you have single pane windows, try reflective window film that clings (no adhesive) like this: https://www.amazon.com/dp/B0D5LRKP4Z . It can make a huge difference. Avoid using it on double pane windows, it can put stress on the seal and wear them out prematurely. These did not darken our view as much as I expected. Mylar 'blankets' over the windows are even cheaper and more effective: https://www.amazon.com/dp/B00DZ1NFSK . You'd have to tape them up and they can be a bit noisy (crinkling sounds when air passes by) and they will really reduce the amount of light that comes in... but they work to keep heat out. Avoid creating heat in the house (over, stove, etc); smaller electric appliances like an instant pot, electric kettle, etc give off far less heat. Moving air cools your body without cooling the room, so use fans whenever possible. Cold drinks also help A LOT, so keep a pitcher of water in the fridge or a big insulated thermos of ice water at the ready.