What a coincidence! I live in Louisiana near the Gulf. My room faces east, so after noon, there is hardly any light. That's one thing I hate about this house. The living room should have tons of windows that look out on the backyard. There is nothing to look at out of these windows except the house next door! The master bedroom is similar with the tray ceiling and the only overhead light from a ceiling fan, but the walls are a pale sage green with some gray undertones. I don't get that same "hot" feeling in here, even though the room is much more cluttered with furniture. It always feels "crisp and cool" in here. I wish I could explain what I'm trying to say better! I think I'll start looking at grays. I'm just worried about my drapes and other stuff. I usually naturally gravitate to golds, greens, crimson, and oranges. Will this work with grayish-blue?

any chance to have the trees thinned? (do you own the trees....). an arborist can remove some limbs giving you more light in your house which is a wonderful thing regardless of paint color.

I don't think the issue is the color, I think it's the lighting. What is the material used for the ceiling? Is it dry wall over concrete or is it drywall over wood? If the latter, I'd consider adding recessed lighting to brighten the space. Put them on dimmers so you can adjust as necessary.

There are many expamples of rooms with dark walls that work beautifully. It is unusual to have an entire home with dark walls. Usually when you have a room with dark walls you compensate with light flooring and furniture, light trim, light artwork and light window coverings, ceiling. It isn't like you are placing black furniture in a black room. Usually you also don't paint the entire home with dark walls - it is reserved for the rooms where you want more drama or can work the look. Good lighting is necessary in dark rooms, it is also necessary in light rooms to make the colors sing and necessary wherever you do any activity where lighting is needed . . . in other words every room needs good lighting. Since these guys are first time home owners, they probably don't have the funds to gut the house, so before picking a paint color that they love and want, they need to look at all the things that have to stay in the house (can't afford to replace any time soon). They also need to look at all the items that they love and want to keep in their home (art, sculpture, furniture). and pick a color palette that works with those elements. If they are just painting they will need to work with existing flooring, counter tops, cabinets, furniture, window coverings, art work . . . Picking colors can't be done in isolation. Everything in your home comes together as a beautiful quilt of textures and fabrics and colors and styles. You can't just take a random handful of scraps from Joanne fabric and expect to make it look beautiful together any more that you can randomly go into a clothing store and buy any pair of pants and any shirt off the rack and expect that by some miracle it will fit you perfectly and create the perfect look that makes you feel like a 10 walking out the door.