This page shows the different variations of the Temperatura wewnątrz from an Icons8 icon pack. Feel free to resize and recolor the icon, and then download the icon in PNG format for free. Icons are available in PNG and vector.
This image for temperature inside depicts the outline of a house. It is in the shape of a square, with a roof that is slanted upwards at the top. In the center of those there is a large thermometer symbol.