A man from Lachine says after smart meters were installed in the building where he lives, Hydro-Québec tried to charge him five times what he normally pays for electricity.

Bob Aubertin uses Hydro-Quebec's equalized payment plan, paying the same amount each month based on estimated consumption.

When it came time to renew his payment plan, he got a shock.

"Our existing budget was $132.99. The new one was going to be $534.65,” said Aubertin, who lives on the second floor of a duplex in Lachine.

Aubertin says he was even more shocked by Hydro-Québec's response when he called to complain.

"They said, ‘These are the numbers — that's what you have to pay. If you object, go out and hire a master electrician at your cost. Then we will judge whether we send someone,’" Aubertin told CBC News.

He hired his own master electrician, who discovered that Hydro-Québec had made a big mistake.

"What they were doing is reading my landlord's meter and charging it to us," Aubertin said.

Hydro-Québec has since acknowledged the problem and reimbursed Aubertin for the cost of the electrician.

Aubertin told CBC News that he’s still upset because he had to take the initiative to find the problem and also wonders how many other Hydro-Québec clients might be having the same problem and not even realize it.

Switch made by accident

Hydro-Québec told CBC News that Aubertin was told to hire an electrician himself because, most of the time, the problem is with the client's own electrical sockets – and not the meter.

"When an installer goes to a location to replace a meter, he must carry out several verifications to make sure he's at the right meter," Hydro spokesman Patrice Lavoie said. "In [this] case, the verification was not automated — it was done with a pen and paper.

"Unfortunately, there was a switch between the meters of the client and the meter of his neighbour."

Lavoie said Hydro-Québec has installed about two million smart meters, and an overwhelming majority of them function properly.