Why natural gas?

According to the U.S. Census Bureau, here are just a few of the reasons home buyers prefer homes heated with natural gas:

  • Natural gas is more economical
    Gas can significantly cut your energy bills, depending on where you live and your energy usage.
  • Natural gas is efficient
    Using gas directly for space heat, water heating, cooking, and drying decreases our region’s demand for electricity.
  • Natural gas is reliable and convenient
    Gas is delivered directly to your home through underground piping and will not leave you stranded in inclement weather as electricity can. Using natural gas means no storage tanks, no running out, and no waiting for delivery as with oil and propane.
  • Natural gas is environmentally friendly
    Clean-burning natural gas is the most efficient fossil fuel available and the least taxing on the environment.

Commercial or Industrial Business Usage

Interested in natural gas information for commercial and large commercial business usage? Use the links below to determine which information best suits your gas needs.

Are you: A commercial business using?less?than 2,000 therms a day and?less than?200,000 therms annually?click here.


Are you: An industrial and large commercial business using 200,000 therms or?more?annually?click here.

RS – (Residential): ?This rate is applicable to any customer using natural gas for residential purposes.

GS-1 (General Service):?Small commercial or light industrial business will be billed for natural gas service under the?GS-1?tariff.

Residential and commercial rates charged by Intermountain Gas Company (IGC) for the gas delivered to the customer include the following components:

Per Therm?Charge?– The ?Per Therm?Charge is the actual cost of the natural gas purchased from suppliers plus the cost of transporting that gas through various pipelines in Intermountain’s system then delivering the gas to customers. The gas cost portion of the Per Therm??Charge is trued-up in an annual Purchased Gas Adjustment (PGA) mechanism.

Customer Charge?– The Customer Charge helps to recover a small portion of costs incurred to provide service to your home or business.

Intermountain purchases natural gas through an unregulated wholesale-commodity market, using a mix of long-term and short-term contracts with independent suppliers. The price customers pay for natural gas reflects what Intermountain actually pays for the fuel.? Commission rule does not entitle the utility to make a profit on the gas-supply portion of the bill.

A?PGA?is a method of reconciling or “truing-up” the prices Intermountain pays for purchasing and transporting natural gas to customers with the rates that are charged for the gas that is delivered. The first part of this process involves looking ahead and establishing the best projected price of natural gas in the upcoming year.? The second part looks back and calculates the difference between the previous projected price and the actual price. Sometimes that difference is positive and the customer receives a credit.? If the difference is negative, a surcharge is applied to the bill.

The price Intermountain pays for natural gas fluctuates daily, yet the rates charged to the customer are normally adjusted only once each year through the PGA mechanism.? Intermountain’s earnings do not change as a result of a proposed rate change reflected in a PGA.

The cost of transportation, storage and distribution of natural gas includes the maintenance of pipelines, meters and other equipment.? It also encompasses the cost of billing customers and allows for a moderate level of profit for Intermountain’s investment in the local distribution system.? Any request for higher rates is reviewed by the Idaho Public Utilities Commission.


The following cost comparisons for Natural Gas space heating vs. other energy sources are based on the current average therm consumption for all IGC RS customers (742 therms per year).

The Electricity comparison is based on 110% Efficiency of Electric equipment and current published rates as of 04/01/2022.

Based on Intermountain Gas prices approved 10/01/2021

Energy SourceEfficiencyAnnual Energy CostMonthly Energy CostSavings With Gas
IGC Natural Gas Space Heat80%$513.10$42.76
Idaho Power Resistance Space Heat110%$1,458.26$121.5265%
City of Idaho Falls Resistance Space Heat110%$997.97$?83.1649%
Rocky Mountain Power Resistance Space Heat110%$1,794.14$149.5171%
Oil Space Heat @ $?2.69/Gal80%$?2,020.71$?168.3975%
Propane Space Heat @ $1.?66/Gal82%$?2,098.26$?174.8576%