I also recommend having some style of dehumidifier in the condo because lowering the humidity in the summers in the condo can make you feel much cooler for much less
I guess one of the all time best tips I can supply you for saving energy on your cooling and heating costs is to invest in the most efficient heating and A/C system you can find. Get a reputable company to install it and get a nice repair system from them and you will be set for years. I like to stick with the top name brands when it comes to heating and A/C machines because they just run better and last longer than the cheaper no name brands. The efficiency is incredible nowadays with the latest machine and my power bills are almost as low as my WIFI bill each month. I would care about switching to a solar heating and A/C system in a single afternoon once I recognize that it is advanced enough to beat the electric system that I have in my condo now. I suppose that they are always really working to improve things in the field and can only imagine what they will be like in another twenty years or so. I may invest in a geothermal heat pump a single afternoon when my current heat pump is old and ready to be upgraded, but I am pretty glad with how much, or how little, my power bills are during the winters. I also recommend having some style of dehumidifier in the condo because lowering the humidity in the summers in the condo can make you feel much cooler for much less. Installing ceiling fans in each room you frequent is another way to trim back on cooling costs. You could also get zoned heating and cooling like I have to avoid heating or cooling the whole house.