Cooler weather is approaching, and your furnace needs to be in tip-top shape so that it will keep you warm and not break down. But if you’ve been having problems with it lately, you may want to consider replacing the furnace. That can be an expensive proposition, so it’s not a decision to make lightly. However, sometimes the furnace is simply too old or in too poor a shape to keep going. If you see any of these five signs, it’s time to start furnace shopping.

1. Do you see rust, cracks, or anything else around the furnace or on its housing? If so, replacement is necessary. These are signs that the furnace is just too old and won’t be able to work for much longer. Furnaces have life spans of about a couple of decades, but they can conk out earlier than that. Cracks can also lead to carbon monoxide leaks, so don’t delay replacing the furnace in that case.
2. Loud noises, rattling, unusual sounds, and other abnormal behavior indicate the furnace needs to go. These are signs that the parts inside are wearing down and are not going to last.
3. If rooms in your home are being heated unevenly, with some very warm and others chilly, that’s an indication your furnace isn’t putting out enough power. This is especially the case if you keep turning up the thermostat and still can’t get the rooms to warm up evenly.
4. Check the pilot light. If it’s blue, it’s good, but if it’s yellow, that’s a bad sign. The mixture of gas in the furnace is not optimal and could be downright dangerous if it includes carbon monoxide. If you see a pilot light that’s yellow, call your gas company immediately for an emergency inspection.
5. If your home has started having problems with humidity and condensation — other than on the window glass — get the furnace checked out and be prepared to start looking for replacements.

Don’t wait for the furnace to start having further problems. Get a repair person out to your home to inspect the furnace, and replace the furnace if necessary. The last thing you need is for the furnace to stop working in the middle of a deep freeze, especially since new furnaces will be more expensive then due to demand.