Jerry Sutherland
Heat pumps are refrigeration- cycle devices that use electricity…
Planning the Installation
There’s a variety of great DHP products on the market today, and we’ve installed quite a few brands over the years. But we rely mostly on Mitsubishi, Daikin, and Fujitsu, all of which offer multiple sizes and models with different features. In deciding which DHP to use for a given installation, we base our choice on the specific combination of features needed, not the nameplate.
Planning the layout. In zoned systems with a fan coil in every room, placement of the units can be fairly flexible. But in a single-zone system, it’s critical to put the indoor unit where it will best distribute conditioned air to the desired rooms. Ideally, it should go fairly high on a wall so furniture and other obstructions don’t interfere with circulation of the conditioned air, and in as central a location as possible. Recessed-ceiling and low-wall units are also available for applications where a high wall location isn’t possible, or for customers who just prefer their appearance (Figure 4).
All indoor fan coils have adjustable louvers to direct the flow of conditioned air as needed. Some models allow the user to choose an oscillating setting that will sweep the airflow back and forth or set the louvers in one position (so they blow air in the direction of a hallway, for example, to help heat or cool outlying areas of the house). This feature can usually be operated with a remote.
Some DHPs from Mitsubishi include a feature the company calls “i-see,” which uses a roaming infrared sensor to locate the coldest or hottest part of the room and then adjust the louvers to blow conditioned air in that direction. That sounds good, and we find that it can work well in a system with a fan coil in every room. But we recommend against using this feature in single-zone systems, because the sensor tends to direct the airflow continuously toward a window or other localized cold spot, defeating the goal of moving as much conditioned air as possible to other rooms in the house.