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Comfort Plus Centrally Ducted Heating System

The Comfort Plus unit is designed to be the main heating system for residential or commercial applications. During off-peak hours, the Comfort Plus unit converts electricity into heat and stores that heat in specially designed, high density ceramic bricks. The Comfort Plus system has the heat storage capacity to provide total comfort 24 hours a day, while allowing the user to utilize low cost off-peak electric rates to achieve low cost and affordable heating.

The Comfort Plus unit is easy to operate. The amount of heat stored in the brick core is automatically regulated in relation to outdoor temperature and the heating requirements of the user. When the room thermostat calls for heat, heat is extracted from the unit's core storage and is distributed evenly into the home until the heat call has been satisfied.

The Comfort Plus unit has sensing devices that monitor the core, the supply and the discharge air temperatures to ensure maximum safety while providing optimum comfort. A heat pump, air conditioner, electronic air cleaner, central humidifier, programmable thermostat, etc., can easily be integrated to offer year round comfort. The Comfort Plus unit can be used as a stand alone furnace or can be used with a air-to air heat pump to realize even greater efficiency and energy savings.

It will allow consumers to enjoy clean, cozy, electric heat 24 hours a day, while realizing a significant savings on their heating bill. 


  • 100% Efficient (or greater if installed with a heat pump)

  • Low Cost Electric Heat

  • Clean and Comfortable

  • Safe and Reliable

  • Easy to operate

  • Minimal maintenance needed

  • Air conditioning easily added

  • Easily interfaces with most heat pumps

  • Microprocessor Control

  • Digital Display indicates unit operation status

  • On-Board diagnostics

  • Power Line Carrier (PLC) wireless communication

  • Soft Start/Smart Charging

  • Automatic core charging

  • Auxillary Load Control capabilities

  • Incoloy Sheathed, Long Life heating elements

  • Optional Time Clock Module available

  • For Residential or Commercial applications

  • Backed by a Five Year Limited Warranty from date of installation

A separate 200 amp circuit box is needed in the consumers home to handle the ETS Unit in the home. You would need to contract an electrician to upgrade your service to handle the load of the unit along with the proper meter sockets and wiring. *reprinted from Steffes Inc.

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Comfort Plus System Installed with a Heat Pump

Air to Air Heat pump systems are known as one of the most efficient methods of heating and cooling. Utilizing a Comfort Plus 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 one of the lowest operating cost options available.

In heat pump applications, the Comfort Plus unit replaces the resistance strip 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 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.

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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. Room thermostat in the home is set to desired comfort level. If room temperature decreases below room temperature 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 (shown at 68°F) across the air filter and the heat pumps A-coil extracting heat from the coil as it passes through it.

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. Air temperature after coil in the diagram is shown at 85°F.

5. If air temperature after the heat pump coil is below a comfortable level (generallly 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. In the diagram, the conditioned air is shown at 95°F.

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Since heat pumps generally have an operating efficiency of 150% - 300% or greater (depending on outdoor temperature), the Comfort Plus system first utilizes the heating ability the heat pump offers. If the heat pump doesn't have the ability to satisfy comfort and space heating requirements, the Comfort Plus system starts to work with the heat pump utilizing low cost, off-peak energy to ensure comfort for the user at all times. Combining the heat pumps efficiency with the "off-peak" Comfort Plus system yields very low operating costs for the end user along with great comfort.



Comfort Plus Hydronic Heating System

The Comfort Plus Hydronic system adds a new dimension to heating by blending hydronic heating with Electric Thermal Storage (ETS) Technology. During off-peak hours, when electricity costs and energy usage generally are substantially lower, the Comfort Plus Hydronic unit converts electricity into heat and stores that heat in specially designed high-density ceramic bricks located inside the unit. Through the use of a heat exchanger, this stored heat is transferred as needed from the storage media to a water or glycol solution, which is circulated to areas where the heat is needed. The Comfort Plus Hydronic system has the ability to utilize off-peak, time of day (or time of use), demand based electric rates to generate savings for the consumer while delivering the many benefits associated with hydronic heating.

The system is extremely flexible and can handle multiple heating zones. Heat can be delivered via a radiant floor system, baseboard radiation, free standing radiators, a forced air system or almost any combination of zoned delivery systems. The Comfort Plus Hydronic can also be used as a supplement to a single or multiple heat pump system installation. The built-in microprocessor provides the ability to easily adjust output water temperature, thereby reducing or eliminating the need for costly add-on controls.

The Comfort Plus Hydronic system is easy to operate. Just set the room thermostat to the desired comfort level and enjoy the safe, clean, reliable and economical heat this off-peak hydronic system provides.


  • Programmable microprocessor based control system allows for customization to user's and power company's immediate and future needs

  • Built-in circuit breakers/power disconnects

  • Selectable primary loop temperature

  • Water zone temperature can easily be set and adjusted by the installer or it can automatically adjust based on weather conditions

  • Built-in controls allow for interfacing with heat pumps or air conditioners

  • Built-in auxiliary load control signaling system for devices such as an air conditioner, and water heater.

  • Digital display indicates unit operation

  • Automatic core charging

  • Optional time clock module available

  • Optional air handler and static recovery unit are available

The Comfort Plus Hydronic heating system is ideal for residential or commercial applications to include:

  • Radiant Floor Systems

  • Hydronic Baseboards

  • Free Standing Radiators

  • Supplemental Heat for a Heat Pump

  • Make-up Air Tempering and Demand Management

*reprinted from Steffes Inc.



Heat Storage Room Units

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What is Thermal Storage? During off-peak hours, ETS heaters convert electricity into heat and store that heat in specially designed high-density ceramic bricks. These bricks are capable of storing vast amounts of heat for extended periods of time. This stored heat is circulated evenly and quietly by a fan inside the unit as the room thermostat calls for heat. The ETS equipment is easy to operate and requires very little maintenance. The amount of heat stored in the brick core of the heater is regulated (either manually or automatically) according to seasonal weather conditions. The on-board room temperature thermostat is set to your desired comfort level and will control the delivery of heat from the ETS heater.

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These units are sized based on your room area and are ideal for hard to heat areas or incorporated into dual fuel or time-of-day rates. The units are wired 220 direct, store heat in the off peak mode and distributes this heat during the on peak times.



End User Cost of Operation Comparison


Heat loss of home 65,000 btu Outside Design Temp. -15

Heat Pump

Electric Rates:



Standard Electric









Heat Pump with Comfort Plus

-HP kWh On-Peak



-HP kWh Off-Peak



-Comfort Plus (ETS) kWh






Annual Efficiency



Fossil Fuel Costs



Base Chg.







-Fuel Oil





-Natural Gas





Cost of Operation




Ext. Cost

Standard Electric





Off-peak Electric(ETS)





w/Std Resistance





Geothermal Heat Pump





w/Comfort Plus










Fuel Oil





Natural Gas