Enter the total heat output and the electricity used into the calculator to determine the HSFP.

HSFP Formula

The following formula is used to calculate a heating seasonal performance factor (HSFP). 

HSFP = HO / EU
  • Where HSFP is the heating seasonal performance factor (BTU/watt-hr)
  • HO is the total heat output over the season (BTU)
  • EU is the total electricity used (Watt-hr)

To calculate HSFP, divide the total heat output over the seasons by the total electricity used for the season.

What is HSFP?

Definition:

HSFP, short for heating seasonal performance factor, measures the efficiency of air-source heat pumps and is a ratio of the heat output to electricity use.

How to calculate HSFP?

Example Problem:

The following example outlines how to calculate HSFP.

First, determine the total heat output for the seasons. For this example, the heat pump generated an output of 100,000 BTUs.

Next, determine the electricity use during the same seasons. In this case, the electricity usage was 25,000 Watt-hours.

Finally, calculate the HSFP using the formula above:

HSFP = HO / EU

HSFP = 100000 / 25000

HSFP = 4

FAQ

What factors can affect the HSFP of a heat pump?

Several factors can influence the HSFP of a heat pump, including the climate in which it operates, the quality of the heat pump’s installation, its maintenance history, and the specific model’s efficiency. Operating conditions, such as the temperature differences between the inside and outside of the building, also play a significant role.

How does HSFP compare to other efficiency metrics like COP or SEER?

HSFP, COP (Coefficient of Performance), and SEER (Seasonal Energy Efficiency Ratio) are all measures of heat pump efficiency, but they focus on different aspects. HSFP measures the efficiency over the heating season, COP measures the efficiency of a heat pump at a single temperature condition, and SEER measures the cooling efficiency over the cooling season. Each metric provides valuable information depending on the context and the specific performance aspect being evaluated.

Can HSFP be improved, and if so, how?

Yes, the HSFP of a heat pump can be improved through several methods. Regular maintenance, such as cleaning filters and checking for leaks, can help maintain efficiency. Upgrading components, such as installing a more efficient outdoor unit, can also improve HSFP. Additionally, ensuring that the system is correctly sized for the building and optimizing the ductwork can lead to better performance and higher HSFP values.