Residential Hydronic Furnace with Heat Pump

Comfort Plus Hydronic System Installed with a Heat Pump

Heat pump systems are known as one of the most efficient methods of heating and cooling. Utilizing a Comfort Plus Hydronic unit with a heat pump allows the heat pump's high efficiency to be combined with off-peak electric rates making this heating and cooling system the lowest operation cost option. In addition, the Comfort Plus Hydronic unit ensures comfort regardless of outdoor temperature.

In heat pump applications, the Comfort Plus Hydronic unit replaces the resistance strip heat or secondary heat, which is typically required as a supplement or backup to heat pump systems, with low cost, off-peak stored heat. As outside temperatures decline the stored heat in the Comfort Plus Hydronic unit is used in conjunction with the heat pump's heating capacity to satisfy comfort requirements. During on-peak hours or when the demand for heat is at the point where the heat pump alone cannot satisfy the heating requirements, the stored heat is used to supplement the heat pump. The Comfort Plus Hydronic unit allows the heat pumps efficiency to be utilized even during cooler outdoor temperatures.

To interface the Comfort Plus Hydronic unit to a heat pump, the Steffes Air Handler  is required. The Steffes Air Handler not only allows the Steffes Comfort Plus Hydronic furnace to supplement the heat pump and provide comfort modulation when needed; but, it also will direct the heat lost statically through the furnace’s outer panels into the ductwork for delivery to the living space (automatic static heat recovery).

The Comfort Plus/Heat Pump system offers significant benefits:

  • Provides great comfort 24 hours a day
  • Provides for a high efficiency, low cost heating and cooling system all in one
  • Optimizes system performance by allowing the heat pump's efficiency to be fully utilized
  • Eliminates the cool discharge air temperatures associated with heat pump systems during low outdoor temperatures
  • The Comfort Plus/Heat Pump combination, when used with off-peak electric rates, is the most economical heating and cooling system available.

How the System Works

  1. The room thermostat in the home is set to desired comfort level. If room temperature decreases below the room thermostat set point, the system is energized to deliver heat.
  2. Upon a heat call from the room thermostat, the heat pump's outdoor compressor unit is energized and warms the A-coil in the return air duct of the Comfort Plus unit. At the same time, the Comfort Plus unit's supply air blower is energized.
  3. The supply air blower draws air from the home across the air filter and the heat pumps A-coil extracting heat from the coil.
  4. A sensor monitors air temperature after the A-coil. If the air temperature is warm enough to provide comfort to the homeowner (generally 90° F or higher), the supply air blower simply delivers the warm heat into the home through the supply air duct.
  5. If air temperature after the heat pump coil is below a comfortable level (generally less than 90° F), the Comfort Plus unit's core blower will modulate low cost, "Off-Peak" stored heat into the duct stream so comfortable heat (generally 90° F or higher) can be delivered into the home.
  6. Since heat pumps generally have an operating efficiency of 150%-300% or greater (depending on outdoor temperature), the Comfort Plus system allows the heat pump to satisfy as much of the heating requirement it can on its own. If the heat pump doesn't have the ability to satisfy comfort and space heating requirements, the Comfort Plus system modulates into the duct the precise amount of its stored, low cost, off-peak heat to ensure comfort for the user at all times. Combining the heat pump's efficiency with the off-peak Comfort Plus system yields very low operating costs for the end user along with great comfort.