Washington ? The red-flag April 15 tax-filing deadline has passed.

But throughout the year, you have to make decisions that affect your tax situation. It’s already time to start considering what moves this year will have an impact on your tax return next year.

If you are thinking about a purchase, see whether there are tax breaks associated. For example, here’s a question during a recent online chat: “I’m considering installing a new furnace and heat pump to take advantage of the 2009 tax incentive. What are the tax implications?”

Before I answer that, I need to point out that you should never make a financial decision based solely on the tax implications. Certainly, how the move will affect your tax liability should be considered. But it shouldn’t drive your decision.

As for installing qualified energy efficiency products in your principal residence, the American Recovery and Reinvestment Act of 2009 extended the tax credits available. The credits for energy-efficient appliances and products increased from 10 percent of cost to 30 percent, with a new maximum credit of $1,500. The credits are available for products installed Jan. 1, 2009, through Dec. 31, 2010.

So if you were planning to upgrade your furnace and heat pump, you might as well take advantage of the tax break. A credit is much more valuable than a deduction. A tax credit reduces dollar-for-dollar the taxes you owe. A deduction only eliminates a percentage of the tax owed.

Another online question: “I am considering rolling my student loan into my mortgage refinance to take advantage of the lower interest rate. I plan on continuing to pay my student loan at the same rate (not stretching it out over 30 years). Are there any tax implications for this? I assume not, since both are tax deductible. And are there any other considerations?”

Generally, the personal interest you pay is not deductible on your tax return. However, there is an exception for student loans. For 2009, the student loan interest deduction up to $2,500 is eliminated if your modified adjusted gross income is $150,000 or more (if filing a joint return). For all other filing statuses you can’t take the deduction if your modified AGI is $75,000 or more.

That $2,500 deduction is a nice break. But the deduction for mortgage interest is probably the most coveted tax deduction available. Still, there are some limitations. You can only deduct the interest on the first $1 million ($500,000 if married filing separately) in home loans on a first and second home.

If you refinance, only the interest on the amount you borrow to pay off the old mortgage is deductible. The IRS classifies this as home acquisition debt. Any debt not used to buy, build or substantially improve a qualified home is not considered home acquisition debt. This debt qualifies as home equity debt. The interest deduction on home equity debt is limited to $100,000 ($50,000 if married filing separately).

So it would appear that refinancing and paying off student loan debt are the better tax moves because of the larger deduction. But is it the best financial move?

Typically, student loans come with a hardship provision. Should you have difficulty paying your student loan because of a job loss or illness, you may qualify for a deferment or forbearance for up to three years. You won’t get that kind of break with your mortgage.

A deferment is a temporary suspension of loan payments for specific situations such as re-enrollment in school, unemployment, or economic hardship. You don’t have to pay interest on the loan during deferment if you have a subsidized federal student loan or a federal Perkins Loan. With forbearance, your payments can be temporarily postponed or reduced. Unlike deferment, whether your loans are subsidized or unsubsidized, interest accrues. Various hardship payment options are also available for private student loans.

Too often I find people pile debt onto their mortgage because the interest is deductible. But long term, this may not be the wisest financial decision.