If you're tired of paying hundreds of your hard-earned dollars each winter to keep your home at a comfortable temperature, you may be investigating ways to help cut your energy costs that don't involve sitting huddled under blankets or curled around a portable space heater. Fortunately, identifying the "weak links" in your home doesn't need to be a difficult process. Read on for a few minor (and major) modifications you can make to your home to improve its energy efficiency. 

Repair or replace drafty windows

Windows can be responsible for up to a third of your home's total heat loss during winter months -- so replacing drafty windows or patching cracks may have an instant and dramatic effect on your utility bills. 

If your windows are relatively new, but you still notice a slight breeze or feeling of cold air when standing nearby, you may have small leaks in the drywall around your window, or even in the window frame. These can usually be corrected through the application of wood or drywall putty on any visible cracks. This putty has a clay-like texture and quickly dries to resemble the surrounding wood or drywall. Wood putty is available in a variety of colors, and you should have no problem selecting a shade that will complement your existing door frame. However, if you're going to be patching your drywall, you may want a small container of touch-up paint to match your current paint job and keep this repair as unobtrusive as possible.

For cracks or openings that are too small to be seen with the naked eye, an insulating window film may be able to help. This film is made of a thin plastic -- similar to the plastic wrap you may use to keep foods fresh. By applying this film over your entire window surface and window frame, you'll be able to keep warm air from being lost through microscopic cracks. You'll also be able to prevent any rain or snow from seeping into these cracks from the outside, potentially causing expensive damage to your window and the wood and drywall surrounding it.

If your windows are single-pane or decades old, it's likely they've lost any insulating properties they may have once had. Replacing these windows is your best bet to reduce heating costs. For those whose budgets are unable to support the sudden purchase of multiple windows, you'll want to start with the windows that are in the worst shape or are located on the north side of your home (and therefore receive the least sun exposure). 

Look into renewable energy

In some cases -- particularly if you have a large and relatively new (or recently renovated) home -- your energy cost problem may not be due to any inefficiency on your home's part, but simply your use of an expensive or non-renewable resource to heat your home. If you currently use natural gas, electricity, or heating oil, you may find that your energy costs drop significantly simply by converting to an alternative fuel source.

Those who heat with oil may be able to switch to biodiesel without making any modifications to your existing furnace or boiler. Unlike heating oil, which is derived from crude compounds, biodiesel is made from vegetable and animal fats -- making it cleaner-burning and more renewable. You'll generally want to start this process by mixing in a very small amount of biodiesel with your heating oil supply. You'll be able to gradually increase the proportion of biodiesel in your mix until you've reached a level that's comfortable for your home and your wallet. 

If you're planning on staying in your home for the foreseeable future, you may also want to consider investing in a geothermal heat pump. Rather than using the combustion of a fuel to provide heat, geothermal heat pumps gather heat through pipes buried in the ground -- which stays a consistent temperature year-round, even through the coldest winter months. While these systems can be on the pricey side, a geothermal heat pump should essentially eliminate your heating bills, allowing you to recoup your costs over a few years.