A new microfabricated device for heating and sensing in gases is presented. It is based on the resistive heating of a micro- or nano-metric hollow cylinder of titanium nitride, and measurement of its (temperature-dependent) resistance. This article presents the fabrication and temperature calibration of the device, and illustrates its function as flow meter and thermal conductivity meter. A temperature of 280 °C is achieved at a power consumption of only 5.5 μW, orders of magnitude less than existing commercial hotplate devices. The thermal time constant can be as low as 60-120 microseconds.