The Department of Environmental Protection, Pennsylvania, advises that all heating and cooling systems, including furnaces, be replaced after a flooding. “Corrosion begins inside the valves and controls, and damage may not be readily visible, even if the outside of the device is clean and dry,” they say, and warn that, at best, damage can lead to reduced efficiency. In a worst-case scenario, it can cause an explosion. These risks are not worth taking a chance.

Investing in a costlier new furnace may be an expense initially, but in the long run saves more than just money. Yet, how will you know if it’s time for a replacement? Here are a few pointers.

When Your Furnace is Getting Old

Check the furnace label or consult with the manufacturer to determine when the furnace was manufactured and be sure to have your unit’s model number at hand. Furnaces usually have a life expectancy of 15 to 20 years. So, if your furnace is over two thirds of its expected life span and requires multiple repairs, it may be time to purchase a new one.

When Repairs and Maintenance Become Expensive

Properly maintaining a furnace, such as replacing parts per manufacturer instruction, is necessary to keep it in good condition. Many furnace filters also ensure good quality air in your house, so regularly replacing them is of paramount importance to your health.

However, when the annual costs of maintenance or repair become equal to or exceeds the price of a new one, it might be time for a new one.

When Energy/Fuel Bills Are Increasing Over Time

Like all things, many older furnaces might be working harder to heat up your home or becoming less efficient than a new one, even if it’s not malfunctioning. Check and compare your bills from time to time when your furnace hits its 15th birthday. If they steadily increase, it might be wise to consider buying a new furnace. Higher efficiency will mean spending less on fuel over time.

When a Furnace’s AFUE Rating Is Low

AFUE stands for Annual Fuel Utilization Efficiency and usually a unit’s AFUE rating number is supplied with the product information. The math is simple – the higher a furnace’s AFUE rating, the less you can expect to spend on fuel.

When Your Furnace Is Spewing Dirt or Soot

If soot or other dirt can be seen around the furnace or around its registers, it’s time to seriously consider a new one. This problem means that your furnace has or may be using too much oxygen, which can dry out the air and release irritants. This can have serious health implications for everyone in the house.