Your gas furnace has kept your home warm for years—or possibly even decades. However, even with proper maintenance, your furnace will eventually develop problems that simply aren't worth fixing—and identifying these problems isn't always an easy task. Replace your furnace if you have any of these three problems:

Your Repair Costs Are Out Of Control

It's only viable to maintain your home appliances for so long before replacing them becomes a better use of your money. Most consumers find that replacing their appliances is a better option once their total repair costs have reached or exceeded 50% of the appliance's purchase price. If you've spent more than half of the purchase price of your furnace on repairs over the years, then arranging for yet another burner assembly or thermostat replacement may not be worth your money.

Depending on your financial situation, it may be better for you to take the 50% rule as a rule of thumb. If replacing a single, essential component of your furnace at only a minimal cost will allow it to operate safely and efficiently for several more years, then arranging for the necessary repair may prove to be an ideal short-term solution. However, if you have the money to replace your furnace instead of arranging for yet another repair, then do so. By purchasing a new furnace, you're ensuring your long-term heating costs remain manageable over the years.

Your Furnace Leaks Combustion Fumes

Your gas furnace creates several combustion fumes during normal operation. The fumes created by your burner assembly travel through your heat exchanger and out of your home through a flue or exhaust pipe. However, after being used for several years, your heat exchanger can crack.

Your heat exchanger will develop cracks when it becomes fatigued. Since your exchanger is made of metal, it will expand and contract whenever it becomes hot or cold. After expanding and contracting hundreds or even thousands of times over the years, the weak areas of your exchanger (such as welds or bends) will become prone to cracking—and when cracks finally form, carbon monoxide and other dangerous combustion fumes will waft through your furnace and into your home.

When carbon monoxide inside your home reaches a concentration of 70 ppm or higher, it can cause nausea, dizziness, vomiting, or even death. For this reason, you should replace your furnace if it's likely to leak carbon monoxide and other combustion fumes into your home—especially if you leave your furnace in operation while you're asleep.

It Costs Too Much To Operate Your Furnace

Although your old gas furnace may cost less to operate than an electric furnace, it still consumes an excessive amount of gas. As a result, your monthly utility bill rises significantly throughout the cold months of the year. If you find yourself turning down your thermostat just to make sure you can pay the bills every month, then it's time to replace your old furnace with one that's more efficient.

Modern gas furnaces with a greater number of burners or more powerful blower motors can produce a greater amount of heat with an equal or lesser volume of gas than your current furnace. As a result, your home can be heated quickly without any increase in your monthly utility bill. Additionally, a new gas furnace that heats your home quickly will allow you to leave your furnace active for shorter periods of time. This benefit will reduce both your total gas consumption and the amount of wear that your new furnace sustains.

If you've spent hundreds on repair bills for your current furnace, experienced symptoms of carbon monoxide poisoning, or are tired of emptying your bank account to pay your monthly utility bill, then replace your furnace right away.

Although you can further decrease your heating costs by installing a replacement furnace by yourself, you should always leave the task of replacing your furnace to a professional HVAC contractor, like one from HomeSmart From Xcel Energy. By doing so, you can ensure that your new furnace will operate safely and efficiently for years to come.