I use this bulb in a commercial open heat-resistant ceramic socket in my Bastelkeller. Really excellent illumination - and as a desirable side-effect of this basement is heated by the heat radiation equal to something. In this use, highly recommended. In normal room lighting they should not be used - the versions would almost certainly be charred (ev risk of short circuit.) - The lamp is still a lot of heat from, so not for "energy saver" .....