Using Supplemental Electric Duct Heaters in Heat Pump Systems


Homeowners are increasingly relying on VRF heat pumps and ductless mini-splits to keep their families warm during the heating season. At the same time, commercial property managers are relying more and more on these devices as well, thanks to the ease of installation, simple controls and unparalleled flexibility that they offer.

VRF and ductless mini-splits represent some of the most efficient kinds of heaters on the market. Whereas propane and oil heating systems rely on expensive fuels to operate, these heat pumps produce indoor warmth in a cost-effective, environmentally friendly way.

However, heat pump mini-splits can be overtasked when dealing with subzero temperatures. These conditions cause HP’s to eliminate the efficiency that makes them so desirable and to produce less heat affecting the comfort of the living space.

Installing an electric duct heater for supplemental heating is one of the best ways to address this dilemma. The result is a far more efficiency in terms of the overall system’s Heating Seasonal Performance Factor (HSPF).

Choosing Electric Duct Heaters for Supplemental Heating

There are several ways to mount and install your electric duct heater in a mini-split system. One of the most popular methods is to install the electric duct heater on the discharge duct of the air handling unit, effectively keeping the duct heater unit out of sight.

By choosing a device correctly sized to fit inside the discharge duct and handle the needed additional BTU load, supplemental heating is available when it is needed and not used when the outside temperature isn’t cold enough to need it. In order to maximize efficiency, you’ll need to choose an electric duct heater that offers modulation, such as Thermolec electric duct heaters.

Modulation allows the duct heater to rapidly switch on and off in response to the difference in temperature inside and outside the building it is installed in. Using a duct temperature sensor and an SCR control, the supplemental heater can provide just the right amount of thermal energy to satisfy the need for additional heat.

On extremely cold days, the heat pump outdoor unit shuts off while the indoor air handling unit continues to run. The air handling unit provides the air flow and the electric duct heater provides the right amount of BTUs needed to satisfy the heating requirements.

Heat pump systems are growing in popularity in today’s marketplace because of their impressive performance/efficiency ratings.  With many brands and types toting efficiencies of 400+ %, the energy savings is difficult to ignore.  Unlike the original heat pumps of years’ past (introduced in the 1970’s), today’s heat pump technology produces BTU outputs capable of providing full heating comfort for residential and commercial structures located in environments with outdoor design temperatures down to zero degrees Fahrenheit.   Incorporate supplemental heat, such as a Thermolec modulating electric duct heaters, and the result is a heat pump system with no outside cold temperature restrictions.

EP Sales maintains a large inventory of Thermolec and Greentek products and parts to service the needs of our customers.