A coalition of nearly two dozen Massachusetts state senators has called on state utility regulators to investigate “skyrocketing energy costs” amid freezing temperatures this winter.

The letter led by state Sen. Jake Oliveira, D-Hampden/Hampshire/Worcester, specifically mentions natural gas bills sent out by energy titans National Grid and Eversource, with the latter coming in for particular scrutiny.

In the letter to state Department of Public Utilities Chairperson James Von Nostrand, the lawmakers shared reports of sticker shock among their constituents, with one resident opening a bill totaling an eye-popping $449.91.

“Eversource has attempted to blame these spikes on colder temperatures, increased usage, and rate adjustments implemented in November 2024,” they wrote. “Yet many customers who have kept their thermostats at consistent levels are still seeing drastic hikes, raising questions about the fairness and necessity of these increases.”

On Sunday, state regulators confirmed that they were in talks with natural gas utilities to explore how to shield customers from further price spikes, The Boston Globe reported.

“We are reviewing the letter and will respond to the legislators who have contacted us,” agency spokesperson, Alanna Kelly, said in a statement. “We have listened to ratepayers, and we will be working directly with the gas companies over the coming days to revise their delivery rates to provide relief as soon as possible for their customers.”

Last November, state regulators approved Eversource’s request to boost natural gas bills by 20% to 30%, The Boston Herald reported. The company usually adjusts its rates twice a year, the newspaper reported.

The price spikes also have sparked a consumer revolt, with 3,273 people, as of Monday morning, signing a Change.org petition calling on Eversource to tame its prices.

The petition, started by user Russell Warwick, gives voice to the frustrations felt by customers across the Bay State who have seen their energy bills go up this winter − particularly on delivery fees that have driven up the cost of home heating.

” In one billing period, despite using only $148 worth of natural gas, one customer was charged an astonishing $322 in delivery services. My total bill was more than $539 – a sum many of us cannot shoulder,” Warwick wrote in a post accompanying the petition.

“The shock and confusion was overwhelming,” Warwick continued. “Gas delivery charges exceeding even the cost of the gas itself? Imagine ordering a meal for around $150 and then getting charged an additional $322 for it being delivered.”

In their letter to regulators, lawmakers called for immediate action.

“With winter in full swing, the urgency of this issue cannot be overstated,” they wrote. “We call on the DPU to take these concerns seriously and implement measures that prioritize affordability and fairness for all residents.”