[cypher]

It's a fairly good sized cage so if you have really deep substrate & plenty of shredded tissue for a cosy nest then it should retain heat well, it's important to know what the temperature is rather than guessing so keeping a thermometer in the room is a good idea, if it's less than 65 then you may need some additional heat, I've found the most efficient & economical thing is to use a small oil filled radiator that you can leave on all night.
I've never used a reptile lamp but you do need to take care not to overheat any part of the cage especially the nest area.
If it's really cold I do use snugglesafe heat pads under the cage but with a gap of a few inches between & not directly under the nest.