DALLAS—TXU Energy is offering a system that lets residents adjust their thermostats from any computer connected to the Internet and allows the electric company to turn off customers’ air conditioning when power supplies are stretched to the breaking point.

Officials for TXU and the companies providing the technology say it could help consumers cut their energy bills.

TXU said Thursday it is offering the technology free to residential customers, who would install the thermostats themselves.

The thermostat “is great for customers who want to manage their energy usage, save money and lessen the impact on our environment without giving up comfort or convenience,” said Jim Burke, the chief executive of Dallas-based TXU Energy.

The system also lets TXU turn off customers’ air conditioners for stretches.

Sophia Stoller, a TXU spokeswoman, said at times of peak electricity demand, TXU would turn off customers’ air conditioning for 10 minutes every half hour. TXU would have that option between 1 p.m. and 7 p.m. from May through September, she said.

The thermostats are made by Comverge Inc., and the high speed Internet-connection equipment is being provided by Digi International.