Question: Is there a direct conversion from therms to cubic feet of natural gas? Answer: There is - based on pressure, but I don't have it handy. Either way, a therm is 100,000 BTU.<p> The average heat value of natural gas is 1000 BTU per cubic foot. A BTU (British Thermal Unit) is enough heat to heat one pound of water one degree (F). Natural gas is sold to the customer in units of 100 cubic feet (therm) or in a unit called MCF. A therm represents approx. 100,000 BTU of heating power, enough to heat a normal home for about 2 hours during colder weather. MCF is ten therms, or 1 million BTU's. Prices vary, from as low as $.80 to as high as $1.60+ per therm. Natural Gas is delivered to the customer at a very low pressure, usually less than 1/2 PSI. The pressure is expressed in Water Column (WC), where 28" WC = 1 PSI. Link: Link to Article Link: Clear definition of natural gas terms.