The average price of a gallon of regular gasoline dipped below $2 on Monday for the first time since 2009, according AAA.

The national average for gas was $1.998 per gallon. Gasoline prices last fell below $2 between November 2008 and March 2009 during the recession, according to AAA. Cheaper gas prices have saved Americans more than $550 per driver so far this year, or a total of $115 billion, AAA said.

With crude oil prices under $35 a barrel, and savings on everything from gasoline to heating oil piling up, a key question is whether consumers will spend those extra dollars and help drive the economy further.

Forecasts for average U.S. household spending on heating oil for the 2015-16 winter is $1,282, according to the U.S. Energy Information Administration. That's a savings of more than $800 for a family compared to 2012-13, when heating oil spending was $2,113 or about 39.3 percent higher.

The savings will be significant for low-income families, which spend roughly 10 percent to 15 percent of their income on home heating. In contrast, a family of average income spends about 2 percent to 3 percent of their income to heat their homes.

More than 81 percent of households that use heating oil as their primary heating source are in the Northeast. And about 30 percent of U.S. home heating oil customers are low income, so any energy savings can have a big impact on household finances.

Families using natural gas to heat their homes are forecast to see savings of about $117, with a price drop to $560 this coming winter compared to $677 for the 2013-14 winter, estimates Mark Wolfe, director of the National Energy Assistance Directors' Association, which focuses on home energy assistance.

Coupled with low gas prices, "For a typical family, it will be a bonanza this year in energy savings," Wolfe said.

Economists, including Chris Christopher, director of consumer economics for IHS Global Insight, will be watching key data releases this month including a third-quarter reading on GDP, and consumer sentiment and confidence for December.

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"Employment reports have been good and falling pump prices are helping consumers feel more confident," Christopher said. Anticipated savings in monthly home-energy costs could further lift consumers. "If the trend persists, they'll learn to take that money and put it elsewhere," he said.

Keep in mind a key gauge of U.S. consumer spending — November retail sales — rose solidly. Consumer spending accounts for more than two-thirds of U.S. economic activity.

One potential speed bump to consumers spending their energy savings is, well, saving money.

The personal saving rate, which measures the share of a person's disposable income that is saved, was 5.6 percent in October, a notch higher than the prior month, according to government data. "Why isn't this money moving into the economy like it should?" asked Wolfe of the Energy Programs Consortium.

But Christopher of IHS notes the October data was as much about consumers stashing their income from rising wages, not so much that spending was subdued in certain areas.

Looking ahead to 2016, consumers may save more on energy as lower oil prices are forecast to linger.

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Amid oversupply, Moody's sharply lowered its oil price forecasts for next year. Moody's dropped its price assumption in 2016 for Brent crude oil, the international benchmark, to $43 from $53 per barrel and for West Texas Intermediate (WTI) crude, the North American benchmark, to $40 from $48 per barrel.

Refinery production is also outpacing demand and adding to bulging inventories. This combo of ample production and rising gasoline inventories are likely to keep pump prices relatively low. "And barring any unforeseen shifts in market fundamentals, averages are likely to continue to decline leading into 2016," according to AAA.

Despite short upticks, natural gas prices are also at multiyear lows, as warm weather has hit the prime winter heating season. "Heating degree demand has been weaker than expected in pretty much every metro area," said Paul Hickey, co-founder of the Bespoke Investment Group. "I think the longer-term trend is continued weakness here," Hickey told CNBC on Dec. 14.

So with energy prices poised to stay lower for the long-term, a more confident consumer could be emerging. "Confidence is making a comeback, the stock market has stabilized, pump prices are falling, and job opportunities are looking brighter," said Christopher of IHS.

Added energy expert Wolfe: "The proof will be this Christmas, if consumers spend."