The use of exchange-traded funds in the U.S. is expected to leap from $1.5 trillion now to more than $3.5 trillion by 2017, according to iShares, BlackRock Inc.’s ETF unit.

The company, which stands to benefit from the projected surge, based its analysis on in-house data and from outside sources including Bloomberg, Cerulli Associates and Greenwich Associates.

Financial advisors are expected play a big role in boosting ETF sales, particularly as the fee-based advisory model continues to grow and advisors see low-cost ETFs as a way to build client portfolios both strategically and tactically.

Elsewhere, iShares says it expects the self-directed investor market to be the fastest growing segment of the ETF space, thanks in part to the proliferation of commission-free ETF platforms and increased marketing to that segment.

According to a press release from iShares, the company says half of institutional ETF users expect to increase their ETF use by 2014. And iShares reports that more retail and institutional investors are adding ETFs as core exposures.

In addition, iShares says it expects fixed-income ETFs to grab bigger market share, and that the ETF industry will keep rolling out new products that give investors innovative exposures to the financial markets.