All heating systems are compatible with solar retrofits, but some offer less-costly alterations. Radiant floor systems with the tubing embedded in concrete are normally the best match for solar system integration. The lower temperature required by the radiant floor results in higher collector efficiency, since less heat is lost from the collectors to the surrounding cold atmosphere, and the thermal mass in the concrete provides some storage for night usage. Other common heating systems, like hydronic baseboard and forced-air furnace systems, can also be retrofitted with solar heating systems—but additional storage (at an additional cost) will usually be required. The storage temperature will need to be higher to match the normal output temperatures of these systems, resulting in reduced collector efficiency.