Yes, you can use a lamp dimmer for a cheap temporary fix. In the long run, though, dimmers are unreliable as they do not account for changes in room temperature. All under tank heaters need a thermostat though for the safest control of belly heat. While not the most reliable available, here is a good cheap option that's 1000 times better than either nothing at all or a lamp dimmer - http://www.amazon.com/Hydrofarm-MTPR...arm+thermostat.