The Senate Finance Committee voted yesterday to triple the existing tax credit for installing home insulation, storm windows and weather stripping, and to provide new tax breaks for replacing furnaces and buying wood burning stoves.

Continuing work on President Carter's proposed windfall profits tax bill, the panel agreed tentatively to boost the insulation credit to 50 percent of the first $2,000 a homeowner spends, up from 15 percent under current law.

At the same time, the committee decided to extend the 50 percent tax credit to purchases of replacement furnaces and boilers, even in cases where the homeowner would have had to buy a new one anyway.

The panel also voted to provide a tax credit amounting to 25 percent of the first $2,000 for purchases of woodburning stoves. The Carter administration had proposed a 15 percent tax credit. That move was widely criticized as a political gesture aimed at influencing the New Hampshire primary.

The measures were approved "in principle only." Because the panel has voted so many tax breaks in recent days, committee leaders were afraid they may run out of money. The panel will reconsider the provisions later and possibly pave them back.

Meanwhile, committee Chairman Russell B. Long (D-La.), told reporters he hopes the panel will complete work on the entire windfall profits tax bill sometime next week and sent it to the Senate floor early in October.

Long's timetable, several weeks ahead of the schedule he announced previously, came as a surprise to some observers. The committee so far has spent all its time voting tax breaks and has not even begun to consider the tax on crude oil.

Approval of the increased home insulation credit, which would boost the maximum tax break from the current $300 to $1,000, came despite warnings by congressional staffers that the move might raise home insulation prices by as much as 35 percent.

Enactment of the existing tax credit in 1977 pushed demand up so sharply that it created a shortage of materials and sent home insulation prices so soaring. It also encouraged use of inferior substitutes.

The Carter administration opposed the higher home insulation credit. Assistant Treasury Secretary Donald C. Lubick argued that with energy prices already so high, consumers had enough incentive to install energy-saving equipment.

The committee didn't agree on when the new tax breaks would be- nace in an existing home, even if it simply replaces one that has broken down or worn out.

The higher home insulation credit proposed by Sen. Bob Packwood (R-Ore.), would cost the Treasury $1.4 billion in lost revenues in 1980 and $1.7 billion a year by 1985 and beyond.

The credits for furnaces and wood burning stoves, proposed separately by Senators John Chaffee (R-R.I.) and John Heinz (R-Pa.), would cost$1 billion by 1980, $1.5 billion in 1985 and $2.1 billion by 1990.

Together with tax credits voted in earlier drafting sessions, the panel so far has committed some $7.8 billion a year in revenues by 1985, and up to $12.9 billion a year by 1990, offsetting a sizable portion of the revenues expected from the windfall profits tax.

Long confirmed yesterday he expects the Finance Committee version of the windfall tax to be weaker than that voted by the House, with broad exemptions for newly-discovered oil, hard-to-pump "tertiary oil" and oil from stripper wells.

Approval of the tax credits appears to be part of Long's strategy for prodding the panel into adopting a windfall profits tax. The chairman is said to hope that the prospect of the high cost of the tax credits would heighten support for a crude oil tax to help pay for it.

Come effective. Long said the panel would deal with these and other issues when it reconsiders the proposals later.

The tax credit for new furnaces would apply to the purchase of a furnace.