Ultra low-power electrical hotplates are presented based on Ohmic heating of a small conductive volume (link) sandwiched between two electrodes. The link is fabricated by etching a hole in the dielectric layer between the electrodes and subsequently filling it with TiN deposited via ALD. This results in a hollow vertical cylinder with the walls covered by a conductive (TiN) film with a thickness of 7-15 nm. Devices with micro- $(\oslash \sim2-6 \mu m)$ and nano- ($\oslash \sim100 nm)$ links were fabricated on silicon substrates and electrically characterized (I-V curves). The link temperature as a function of the applied power was estimated. Devices with a micro link reached a link temperature of ~250 ºC with a power consumption of 2.7 mW. Devices with a nanolink exhibited a link temperature of ~280 ºC by consuming only 5.5 µW.