I went to a lot of trouble to install an ERV — a Panasonic model. Brought my CO2 levels down from consistently over 1200ppm to ~500ppm with people in the house. Hot/humid areas make it difficult to bring in fresh air since the moisture in the air can lead to all sorts of issues and obviously it's very inefficient to have 100 degree air coming into the house when you're seeking mid-70s temps indoors. ERVs are designed to address these issues.

Check out a video here to see how these things work (this demo is an HRV, so it doesn't help with humidity, but you can see how well it works when there is a big temperature difference between indoors and outdoors).

https://youtu.be/QOSelUK6dpQ?t=436