A horizontal heat pump is a type of air-source heat pump that is installed horizontally, rather than vertically. This type of heat pump is ideal for installations in areas with limited space, such as attics or crawl spaces. The main advantage of a horizontal heat pump is that it is more efficient than a vertical heat pump, as it requires less energy to move air horizontally than vertically. Additionally, horizontal heat pumps are quieter than vertical heat pumps, as the sound waves travel more easily through the air horizontally than vertically. Furthermore, horizontal heat pumps are less likely to be affected by wind, as the wind can be blocked by the walls of the installation area. Finally, horizontal heat pumps are typically more cost-effective than vertical heat pumps, as they require less energy to operate. All in all, horizontal heat pumps are a great choice for those looking for an efficient and cost-effective way to heat their home.