Customers may have noticed an unwelcome surprise when opening their SoCalGas bill the past couple of months.

The utility says the average customer likely saw rates increase by about $20 from a year ago in December, and $35 from a year ago in January.

But customers have apparently been calling the utility complaining about much higher increases.

“We will sometimes have customers say ‘this is triple what I’ve ever had. Double what I’ve ever had.’ What we tend to find as we look into it is … It’s definitely higher. It’s significantly higher. It’s rare that it’s actually that much higher,” SoCal gas spokesperson Gillian Wright said.

The utility says increased winter demand combined with higher natural gas and shipping costs are to blame for the increases being passed along to residents.

Customers typically use three to seven times more gas in the winter than in the summer, according to SoCalGas.

The price surge comes as consumers are already dealing with a 7% inflation rate, the highest in 40 years.

“My gas bill is $100 more than last month. $29 to $130. I don’t think I’ve ever paid more than $65. I was stunned,” Karen from San Bernardino tweeted.

Another viewer said that her bill was over $200 and the utility recommended keeping her thermostat at 55 at night and 60 during the day when she called for more information.

SoCalGas does offer a number of energy-saving tips on its website.