I've known for quite some time that my house isn't the most energy efficient on the block, but over the years I've managed to let any upgrades slip further and further down the priority list.

A visit last week by a Questar Gas energy auditor changed that. He not only confirmed that I could benefit from more insulation and other upgrades, but let me know there are programs that can help pay much of the cost, including for new windows.

I decided to immediately start with insulation, because a rebate program offered by Questar Gas will be reduced come May 2, which means less of the cost of the job will be refunded if I don't act now.

Insulation is a good first project anyway, experts say, because you'll see the difference immediately in your utility bills. That's especially true in homes built before 1990, said Kelly Larsen of Superior Insulation in Salt Lake City.

Questar and Rocky Mountain Power offer rebates of 35 cents to 45 cents per square foot for insulation upgrades. Homeowners who qualify can get rebates from both companies for the same job, which means a combined rebate of 70 cents per square foot on attic and floor insulation and 90 cents per square foot on wall insulation.

Many contractors are charging about the rebate amount, or less, to install the insulation, which means homeowners end up paying little, if anything, for the upgrade.

Even if you qualify with only one of the utilities, you're still getting a good portion of the job refunded, especially if you shop around for a good deal.

The idea is to contact several companies, because there is a wide range of price offers, and some companies are more motivated than others for work.

Each of the utilities offers lists of contractors. Get bids from at least three, Rocky Mountain Power recommends.

"All of the companies on our Web site know how this program works and how they are to conduct themselves," said utility spokesman Dave Eskelsen, adding that his company also conducts periodic audits of its contractors.

It also is important to read the fine print. Some contractors will let you wait to pay your bill until you get your rebate, but you might have to pay extra for the privilege.

Of the two rebates, Rocky Mountain Power's has stricter qualifying criteria. Qualifying homes must have central air conditioning or a heat pump. And homeowners must be a customer of the company. Residents of Murray, Bountiful, Kaysville, and other cities get their power from municipal power companies, so they are not eligible.

I am one of those, but I do qualify for the Questar rebate, though I need to act fast because its refund will be reduced effective May 2, meaning the work has to be completed by May 1.

The utility's rebates of attic and floor insulation are being reduced to 20 cents per square foot. Wall insulation will be reduced to 30 cents per square foot.

Rocky Mountain Power also wants to reduce its rebate amounts and is seeking permission from regulators.

Representatives for both utilities say the rebates never were meant to cover the entire amount of the upgrades, only a portion. But with the construction industry downturn, companies are charging less to do insulation work, and today's rebates in many instances are covering total costs of the upgrades, said Questar spokesman Darren Shepherd.

Even if you don't beat the May 2 deadline, the new rebate amounts are still a good deal.

And don't stop at just insulation. Check out the benefits of making other upgrades because the utilities offer rebates for upgrading windows and appliances, among other things. Read about them at www.thermwise.com or http://www.homeenergysavings.net/utah/home.

And don't forget that federal tax credits are available. As part of the national economic stimulus package, the federal government has beefed up credits to 30 percent to those who make energy-efficient upgrades this year.

Because the rebates and federal incentives are so substantial, the federal government is figuring out the rules consumers must follow in taking advantage of them.

In some cases, the incentives, when combined, may be equal to more than the amount of the upgrade, said Karen Schneider, a manger with Energy Star in Washington, D.C. But the government probably will draft rules that ensure consumers won't make a profit.

She said consumers should read about the criteria at energystar.com/taxcredits so that they purchase the right equipment or products to qualify for the incentives.

"Thirty percent is such a substantial incentive" that it is really going to get a lot of people thinking about energy efficiency, she said.

"When you think about it, this is pretty big."

Lesley Mitchell writes One Cheap Chick in daily blog form at blogs.sltrib.com/cheap.