What is a Balance Point?

What is a Balance Point?

The heat pump balance point is related to the outdoor temperature and the heating output and efficiency of the heat pump.  The balance point is the lowest outdoor temperature at which the heat pump will operate at capacity high enough  to equal the building’s heat loss.  As the outdoor temperature decreases below this point, the heat pump will need auxiliary heat in order to maintain the desired indoor temperature.  Depending on the model and the efficiency ratings of the heat pump, this could also be considered the point at which it is no longer the most cost effective means to heat the indoor space.

The balance point will vary based on the heating capacity of the heat pump, the cost of the auxiliary form of heat, the efficiency and the building’s heat loss.   There are ways to calculate the most cost effective method to heat your home, keeping in mind that you need precise pricing on your fuel type and the COP (Coefficient of Performance) of the heat pump itself.   ‘Time of Use’ Electricity pricing will also effect which form of heat should be used at which times of day.

Below is an example of calculating this as a rough example to give a basic understanding, this is strictly based on cost and not the heat pumps ability to keep up to the building’s heat loss:

(Based on estimate electricity and propane prices including all delivery and service fees, with a 98% Efficiency Furnace)

Estimated Electricity Cost is $0.27/kWh which produces 3,412BTU

Assuming the COP (Coefficient of Performance) of the heat pump unit is 3.5

You will get 11,942 BTU for every kWh for a heat pump

Estimated Propane Cost is $1.00/litre which produces 25,000BTU

To achieve 50,000 BTU/h with electricity, your cost is $1.13

To achieve 50,000 BTU/h with propane, your cost is $2.00