Ontario households using smart meters now face new time-of-use price periods that will affect how much they pay.

The cheapest time to run the dishwasher or laundry will be after 9 p.m. on weekdays or any time on weekends.

Starting Monday and lasting until April 30, the on-peak times will be from 7 a.m. to 11 a.m., and from 5 p.m. to 9 p.m.

During that period, customers with smart meters will pay 9.9 cents per kilowatt hour. The mid-peak time will run from noon to 5 p.m. Customers will pay 9.1 cents/kWh.

Off-peak use will cost 5.1 cents/kWh.

The Ontario Energy Board predicted the average consumer would save $2 per month as a result of the winter rates.

During the summer period of May 1 to Oct. 31, the peak time is noon to 5 p.m., when air-conditioning demands are highest.

"This is a new program. Many other jurisdictions have moved ahead with time-of-use," Energy Minister Brad Duguid told reporters on Monday.

"They're doing it to encourage people to not engage in peak usage if they can."

People can save a modest amount of money by shifting, he said.

Toronto Hydro said about 60 per cent of its smart-meter customers have seen an increase in their bills, but the utility attributed that to the weather and not time-of-use pricing.

Toronto resident Jane Corry said her hydro bill went up by $105 between August 2009 and this past August.

CTV Toronto's Paul Bliss said over the past year, most people used about 18 per cent more electricity -- mainly because of Ontario's hot summer -- while electricity prices went up about 20 per cent.

Ontario Progressive Conservative Leader Tim Hudak called smart meters “tax machines” and mocked the government for not delivering its long-term energy plan yet.

Bliss explained that the government has been spending on adding clean energy to the grid, which has eliminated the brownouts of the past -- but added that such investments are expensive. In addition, electricity was under-priced in Ontario for most of the past decade, he said.

Donations flap

At Queen's Park, the opposition attacked the government on the timing of the pricing change, but also over donations to the governing Liberals from utility companies.

"Elections Ontario records shows that the Ontario Liberal party accepted thousands of dollars in donations from municipally owned utilities," NDP Leader Andrea Horwath said.

"Why are families, who are already feeling the squeeze, funding the Ontario Liberal party when they are paying their hydro bills?"

As one example, Essex Power Corp. donated $1,700 to the Liberals for the Toronto Centre byelection, which is nearly 400 kilometres from its base of operations.

Duguid responded by noting his government took four coal-fired electricity units off-line and accused the NDP of "opposing important investments" being made to improve the province's electricity system.

He repeatedly said such donations were within the rules.

The Tories said they wouldn't support any NDP motion that would prohibit the utilities from making political donations.

The companies told The Canadian Press that they never made direct donations, but instead purchased tickets to Liberal party fundraising events to network with cabinet ministers.

With a report from CTV Toronto's Paul Bliss and files from The Canadian Press