Control equipment connection diagram [PDF] Certificate of eligibility [PDF] Dual-energy refers to the alternating use of two energy sources for heating a home.

Electricity is used for most of the heating season (i.e. outside temperatures above or equal to -12°C or -15°C, depending on the region) and the auxiliary source takes over when temperatures are very cold (below-12°C or -15 °C). The switch from electricity to the auxiliary source is done automatically by an automatic switching device within the heating system that obeys signals received from a temperature sensor placed outside the home. (Note that the switch-over temperature is generally higher when the electrical component of the system consists of a heat pump).
The main dual-energy combinations are:

• a heat pump with a fuel furnace,
  
  
• an integrated dual-energy furnace (an electrical and a fuel component);
  

Dual-energy offers a more advantageous differential rate 
With dual-energy, customers can better control their energy consumption because:

• Fuel is used at temperatures when it is most effective;
  
  
• customers who choose a dual-energy system conforming to Hydro-Québec standards can take advantage of the DT rate, which enables appreciable savings on their overall energy bill. (This rate is based on a differentiated temperature-based structure.)
  

Little electricity is used during the few weeks of intense cold each year, when the home is heated by fossil fuel. A signal light indicates high-rate periods, so customers can choose to delay using certain electrical appliances and thereby achieve additional savings. Hydro-Québec is offering the differential rate (DT rate).

To qualify for the DT rate, the home must have a dual-counter meter installed by Hydro-Québec.

Subscribing to the DT rate

Customers wishing to subscribe to the DT rate should contact the Hydro-Québec office in their sector (the telephone number is on the electricity bill).

Customers must have a heating contractor of their choice fill out a form attesting that the dual-energy system complies with Hydro-Québec’s tariff by-laws (particularly the sections concerning dual-energy and the DT rate). Customers should also sign the form to confirm that they wish to subscribe to the DT rate. The high-rate signal light is supplied free of charge by Hydro-Québec. However, customers have to cover the costs of testing their system, installing the signal light and modifying the system to meet standards, where required. Customers and contractors requiring more information on this matter can contact Hydro-Québec’s sector offices.

Dual-energy for wise management of our energy resources

The dual-energy population currently stands at about 115,000 DT subscribers, nearly a third of whom have a heat pump.

Dual-energy optimizes the management of Québec’s hydroelectric network by reducing the level of demand during peak periods, usually during periods of intense cold. It minimizes the need for costly thermal facilities that must be started up to meet peak demand.

Rate DT applies to customers who are eligible for Rate D or Rate DM and use a dual-energy system, primarily for living purposes. A dual-energy system heats space, or space and water, with electricity as the main energy source and a fuel as an auxiliary source.

Rate DT consists of a fixed charge plus two levels of pricing for energy consumption. The structure of Rate DT is as follows:

Rates effective April 1, 2009.
Under no circumstances may this table be used to replace the Distribution Tariff.

The prices indicated may be reduced by a discount for electricity supplied at medium or high voltage.

Rate DT, like Hydro-Québec's other rates, assumes that electricity will be supplied at low voltage. When the customer uses electricity supplied at a nominal voltage between phases equal to 5kV but less than 50 kV or invests to transform it, then Hydro-Québec no longer has to pay transformation costs. In return, the utility grants a discount of 0.567 ¢/kWh on the price of energy billed.