NEW YORK (CNNMoney.com) -- Paying for home improvements and cutting your energy bills is no easy task. Just consider, blowing in insulation can cost you $1,500 to $2,000 while replacing your furnace can cost you $4,000 for a typical home.

But energy efficient mortgages let you roll in the cost of improvements into your mortgage. Of course you'll be paying higher monthly payments but ideally your utility bills will be lower.

Here's what you need to know.

In order to qualify for an energy efficient mortgage, you'll need to get an appraisal with a Certified Energy Rater in your state. Check out natresnet.org. These raters test the home and determine what needs to be done in order to get the most energy efficient home. That may mean a new furnace, thicker insulation or newer doors. Keep in mind that getting the rating certificate will cost you about $300.

Bottom line: It's difficult to find a lender. There's a lot more paperwork; the loans are complex and lenders don't make that much money on these loans.

But here's how you can find a lender in your area. Go to EnergyStar.gov and click on find local homebuilders and other partners. Then you'll want to look for lenders who offer special financing.

Another tactic is to log onto the Residential Energy Services Network at NATRESNET.org. These are certified home efficiency raters who can point you to lenders in your area.

Choose your contractor wisely. If the energy improvements didn't cut your utility bill, you're still on the line for a larger mortgage. You can either use a contractor you trust, or find a certified contractor at the Building Performance Institute. That Web site is http://www.bpi.org/. Just remember, improvements must be made 90 days after you close on the house.

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