The rule “if it’s not broke, don’t fix it” no longer applies to furnaces. The rule has changed because furnace technology has changed. Two factors — safety, and efficiency — should impact your decision on when to repair or replace a furnace.
Home furnaces have been extremely safe for decades, but poor repair can make them deadly even when they keep a home warm.
We’ve found the biggest single danger in natural gas powered furnaces is carbon monoxide — the same gas that makes automobile exhaust deadly. Poorly vented furnaces and poorly adjusted flames can release sufficient amounts of the gas to cause sleepiness, or worse. It is always a good idea to have carbon monoxide detector(s) in your home if your home is not all electric. Decades ago we felt that if the flame burns pure blue that was a good indication that we weren’t creating any dangerous gases. Today, we use very sophisticated combustion analyzers as the only true judge of the safety of the combustion process.
Even the best designed systems can become dangerous if not repaired or maintained . The furnace filters that trap dust, animal fur and lint should be replaced regularly, and the flue should be checked to make certain it is venting properly.
Furnace efficiency ratings help you evaluate whether furnace repair or replacement is the smart move.
The most important rating is AFUE (“annual fuel utilization efficiency”) which represents season-long average efficiency. The higher the AFUE percent, the more efficient the furnace.
In general, any furnace that’s more than 10 years old should be replaced, not repaired. We’ve found that natural gas furnaces are the AFUE superstars — the best ones are rated 90 percent or higher. Old oil furnaces (pre-1970 cast iron models) are among the worst, and would be tagged 60 percent AFUE, if rated today.
The only way to make the best “repair or replace” decision is with expert help from a qualified HVAC (Heating, Ventilating, and Air Conditioning) technician.The professionals at P.K. Wadsworth can confirm your current system is safe and determine whether a replacement furnace is justified. Modern furnaces produce so much more heat for the same amount of fuel, they can often pay for themselves over the life of the unit.