It's akin to Goldilocks and the three bears. One bowl of porridge is too hot. Another is too cold. And finally, after much deliberation, she finds one that is just right. Except in this case, though, it's not about porridge. We're talking about insulation.

Insulation's efficiency, along with its environmental impact, ranges widely. Let's look at a few of the most popular insulations on the market today, and maybe find one that is just right for you.

First, why do we insulate our homes? According to the Department of Energy, Heating and cooling account for 50 to 70% of the energy used in the average American home. Inadequate insulation and air leakage are leading causes of energy waste in most homes.

So in short, insulation makes your home warm in the winter, cool in the summer, and it keeps more money in your pocket in the process.

But how much insulation you need can be entirely dependent on the climate of the surrounding area. Use this quick zip code guide to figure how much insulation is necessary in your region.

This will help you establish what R-value (the rating system used for insulation) is proper for optimum efficiency in your home. The higher the R-value, the greater the effectiveness of the insulation. By simply picking the right insulation, even if the material itself is not green in nature, you will be saving energy, and thus making a contribution to a healthier environment.

Here a few typical forms of insulation:

Blankets: These come as rolls or batts and are made from flexible mineral fibers, including fiberglass and rock wool. On the positive side, this form of insulation can be bought with a flame-resistant facing. Additionally, it comes in standard sizing, made to fit between wall studs and floor joists. On the other hand, fiberglass and rock wool are known eye, throat, and skin irritants. And fiberglass is made through an energy intensive manufacturing process, and many fiberglass products contain formaldehyde, a possible carcinogen.

Blown-in: Blown-in loose fill is done by professionals by using equipment to blow in loose fibers or pellets. This can be done with cellulose (a great green option), fiberglass, or rock wool. On the pro side, it is good for oddly shaped areas that rolls don't form to. On the con side, cellulose not mixed with foams is apt to settle and to absorb moisture.

Foam Insulation: And finally, there is foam insulation. Foam insulations, however, are made from petrochemicals and are not recyclable.

You may have found your just right fit in the forms above, but there are still greener options now gaining in popularity. These include recycled paper insulation, recycled denim, hemp, and cotton. Be sure to talk to your contractor about what options would be a good, and green, fit for your new home.