said by »www.hydroquebec.com/residential/···_dt.html :

Hydro-Québec’s dual-energy concept involves using electricity as the principal energy source and a fossil fuel (oil, natural gas) as an auxiliary source. Hydro-Québec’s dual-energy concept is particularly suited to the conditions described below.

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, 10.4°F or -15°C, 5°F). 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.

said by Kringle :

That seems like a pretty high switch-over temperature to me (mine's at 10.4°F). Do you have any control over that?

said by iu97987907907 :

Kringle look at your temps are they Fahrenheit or Celsius?

said by cowboyro :

I will have to get the docs and based on that calculate what the "break-even" point is...

said by hjghghkgk :

Sorry Kringle I missed some of the train of thought, but in the Lower 48 we are told that below 40 degree F we should switch over to fossil fuel or electric to due to heat pump efficiency.

said by CatSnak :

One thing many people forget is that the only true 100% effecient way to heat is with an electric furnace. It is the only heating device where you get a 1:1 ratio of BTU energy out for energy in.

said by CatSnak :

One thing many people forget is that the only true 100% effecient way to heat is with an electric furnace. It is the only heating device where you get a 1:1 ratio of BTU energy out for energy in.