Burner holders and cartridges of a furnace are described herein, which include a support assembly and a manifold. The support assembly is configured to support one or more burners. For example, the support assembly may include a burner holder with a cutout region, which may allow a burner to be moved between an operational position and a disengaging position by twisting the burner. The cutout region can allow the one or more burners to be removed or installed relatively easily, without the need of removing the manifold from the support assembly. The manifold can be attached to the support assembly by, for example, using one or more orifices as fasteners.