Cool paint colors are generally considered to be a good selection for rooms where you want to relax. Colors such as blues and greens are common. Lighter colors also help make a room look longer or larger, so the use of a cool color around your fireplace will help to make a home's ceiling look taller.

On the Other: Warm Color Selections for Accent Walls

Warm paint colors are generally good selections for rooms in which there tends to be a lot of activity. Colors in red or yellow are good warm color choices. Warmer colors tend to make a large room cozier, so if you have a larger living space with a fireplace that you want to make seem more intimate, a warm paint color would be the choice.

Bottom Line

The best way to pick an accent color is to look at the other features in your room such as furniture, wall decor or fireplace material. It is good to take an existing color, but not the dominant one, and use it as an accent wall color. Since warmer colors tend to be placed in a room where a lot of activity takes place and you will likely spend much time gathered around the fireplace, a warm accent color would be a better choice.

Source:

Sunset: Accent Walls

Sherwin Williams: Choosing Paint Colors