Vector's Guide To Gas

Residential gas appliances

Calculating appliance running costs

To determine approximate running costs for an appliance, follow these calculations:

Step 1: Find the appliance ‘Input Rating’ from the appliance specifications.

If this is not expressed in kW/hr, you will need to convert it. Below is a conversion guide:

  • If the appliance ‘Input Rating’ is in Mj/hr, then divide by 3.6 to get kW/hr.
  • If the appliance ‘Input Rating’ is in Btu, then multiply by 0.000293 to get kW/hr.
Step 2: Determine the cost per hour.

Cost per hour

= Appliance Input Rating (kW/hr) x Gas Price per kW

NB: Obtain the appliance Input Rating from the appliance specifications (see step 1), and the retail gas price from an energy retailer. Ensure you are using either the residential price for domestic applications or business price for a commercial project.

Step 3: Determine the total running cost

Total running cost

= Cost per hour x Number of hours in use


Example:

1. The input rating of a gas heater is 2kW/hr.
2.

The price of gas per kW for a residential customer is 4.79 cents*, therefore…

Cost per hour

= 2kW x 4.79c = 9.58 cents

3.

The heater is used on full for 4 hours a day, therefore…

Total running cost

= 9.58 cents x 4 hours = 38.32 cents per day


*Pricing used in this example is for calculation purposes only and excludes daily line charges. Check with your energy retailer for current pricing schedules.

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