The Heat Pumps Mod adds two new temperature-related buildings based on modern real-world technology, each of which must be unlocked via newly-added research projects.
Heat Pumps Mod features
Each of these buildings is more expensive to build than a Heater or a Cooler, and each one requires its own research project to unlock. However, they are more versatile, more space-efficient, and generally more power-efficient than a Heater and Cooler combo.
Heat pump: A reversible heat pump. It functions similarly to a Cooler, but it can either cool a room and exhaust hot air, or warm a room and exhaust cold air, whichever is needed to achieve the target temperature. It is more power efficient than either a Heater or Cooler, but it requires more resources to build.
Be aware that, similar to their real-life equivalents, a heat pump will not operate at optimum efficiency when trying to keep a room cooled below 0°C, or when trying to heat a room while the outdoor temperature is below 0°C. The lower the temperature, the more efficiency will suffer. At -50°C, it will not be able to draw heat out of the air at all.
Geothermal heat pump: This more advanced temperature control building is more expensive to research and to build than a normal reversible heat pump. Because it uses an underground heat exchanger instead of an exhaust fan, it is placed within a structure instead of on an exterior wall. And because it draws heat from the ground instead of the exterior air, it remains an efficient source of heat even in the most lethally cold climates.