Making the choice to repair or replace your furnace is a big decision for a number of reasons. Before jumping to conclusions about what needs to be done, be sure to do a thorough check over your system. Ask yourself these questions:

  • How old is my heating system?
  • Have I seen an increase in repair costs or had frequent breakdowns?
  • How much have my utility bills changed from recent years?

By answering these questions, you can better assess your situation and what steps you should take to remedy any issues.

  1. Old Age – The average life expectancy of a furnace is approximately 15 years. With proper care, they may last longer but with the many industry improvements and more energy and cost-efficient models, keeping your unit for more than 15 years is not recommended.
  2. High Energy Bills – As a furnace ages, it loses efficiency. The system is forced to work harder and, like all things, ultimately requires more energy to carry out its job. This leads to higher utility bills for you and has a negative effect on the environment.
  3. Frequent Repairs – As mentioned, older furnaces work harder to keep up with the heating demands of your home. In time, this can equate to more frequent breakdowns and increasingly costly repairs. If your furnace is more than 12 years it may be time to consider replacing it.
  4. Uneven Temperatures – An old, inefficient furnace can result in some rooms being colder or warmer than others. The system works harder to circulate heat evenly throughout your home but as it begins to decline in productivity, it’s more likely to overheat some rooms (often those in closest proximity to it) and under heat others.
  5. Extra Noisy – Knocking, rattling, humming, and squealing could all be signs that your furnace is nearing the end of its life due to cracks, leaks or other structural issues. If you hear noise coming from your HVAC closet, it’s time to have it checked on.
  • Efficiency – The higher the efficiency (AFUE), the more efficiently the furnace will run
  • Size Matters – Make sure furnace is sized properly to your home.  If it’s too small, it won’t keep your house comfortable during extreme temperatures. If it’s too large it will cycle on and off more frequently putting more wear and tear on the system and its components.
  • Blower Speed – There are three types of furnaces on the market single stage, two-stage and variable speed.  It is best to consult with an HVAC expert for the system that will work best for your home.
  • Zoned Systems – If you have a home where temperatures vary from room to room, a zoned system might be right for you.
  • Installation Quality – The worst mistake that you can make is to compromise installation quality for savings.  A poorly installed furnace can be taxing on the system and your wallet.

Gas valves:

Single stage: A single stage gas valve is simply on or off. It provides 100% capacity to the burner whenever it is on. Manufactures still use a single stage gas valve in their more budget orientated offerings.

Two stage: A two stage gas valve gives the furnace a high and a low setting. For example 60% and 100%. This allows the furnace to run more efficiently on a lower setting until the thermostat calls for more heat. Two stage furnaces have become the the standard today. They provide greater efficiency and comfort by allowing the furnace to run longer, with lower cycles to supply more even heating.

Modulating: Modulating gas valves are the most advanced of the three different valve types. They communicate electronically with the furnace board and the thermostat. They allow the burner to heat up in incremental stages. They generally turn on at 60% and slowly increase output, sometimes as accurately as 1% increments. Manufacturers use these gas valves in their top of the line offering. It should be noted that modulating gas valve do not always translate into any appreciable performance difference. Depending on your home and ductwork, the furnace may ramp up quickly anyway and negate any performance difference or warranting spending extra to have this feature.

Blower Motors:

Variable-Speed: Unlike conventional fan motors, a variable speed blower motor runs at different speeds to precisely control the flow of heated or cooled air throughout your home. Better airflow control means a better balance of temperature and humidity. Using advanced technology, it constantly monitors the data coming from your heating and cooling system, and automatically makes adjustments necessary to meet your comfort needs. It varies the amount of circulated air, compensating for factors like dirty filters or blocked vents by increasing the fan speed. Put simply, it delivers just the right amount of air for the right level of heating and cooling comfort. As an added bonus, a variable speed motor gradually ramps up to full speed. This eliminates the sudden, noisy blast of air that’s associated with standard furnace motors. It also reduces stress on the mounting hardware. And in the cooling mode, it allows the air conditioner to remove more moisture from the air.

Static Pressure: In a more technical sense, static pressure refers to the amount of pressure measured in inches of water when air moves through an object, such as duct work. If it’s a little hard to grab the concept of static pressure, think of measuring that pressure in your HVAC system in terms of the doctor measuring your blood pressure. A blood pressure reading gives the doctor a good indication of your overall health. The same is true of a static pressure reading. It will give the HVAC technician an idea of our system’s general health.

As a matter of fact there is a quick way to determine if the static pressure reading the HVAC technician takes is good or not. Let’s say the fan in the heating and cooling system is rated at “0.5″ of water column”. This figure can be easily obtained by the technician. The 0.5″ reading would correspond to a 120/80, or perfect, blood pressure reading.

If the reading on the HVAC system comes in at “1.0″ of water column” that means there is too much air flow restriction pressure in the unit by a factor of 2. Multiplying both blood pressure figures by 2 gives a corresponding reading of 240/160. This is much too high for a blood pressure reading and also for any HVAC system. Anyone can easily understand this number!

If the reading is “0.75″ of water column” that’s 1.5 times normal pressure. This would give a corresponding blood pressure reading of 180/120. This figure is still too high.

The figures shown using these examples can give the facility manager an easy way to compare and understand what the static pressure in their HVAC system is. If the static pressure in the HVAC system is too high, then the system is not going to operate as well as it should, just like a person’s body.

Heat exchangers:

Condensing technology: A condensing furnace recovers heat that standard furnaces typically lose. While the gas-fired furnace has a long track record for reliability and lower operating costs, the old model with only a single heat exchanger has always had one drawback; Valuable heat that could be utilized to warm your home more efficiently is lost during the combustion process. It goes straight up the chimney.

A modern condensing furnace solves this problem by incorporating not one but two heat exchangers: the primary and the secondary heat exchangers. The secondary heat exchanger simply gives the system a little bit longer to harness all of the available heat. In the process, the exhaust gases often cool down to the point that any vapor present condenses into water. This is why a modern gas furnaces will only lose 3%-5% of heat output through the vent vs. 20%-30%.

Warranty: Almost every brand of modern gas furnace will offer a limited life-time warranty on this component. Some will offer a complete unit replacement should this component fail, included for the first 10 years.

Ignitions:

Electronic Ignition: Gone are the old days of standing pilot light to ignite your furnace. A hot surface ignition is the most common type of electronic ignition today. It is a small metal device that uses an electrical current to heat up to a high enough temperature to ignite the furnace’s burners. The electronic ignition is only turned on when the furnace is ready to begin a heating cycle, and it eliminates the need for a constant fuel supply that a conventional pilot light requires.

Control boards:

Modern Control board technology: Modern furnace control board or logic boards are advanced. They control all the various operations of the furnace. There are various sensors on the furnace that communicate with the control board that will make sure the furnace is operating within specification. Should an abnormality arise, the control board will shut down the furnace for self-preservation. The control board having self-diagnostic capabilities will display error codes allow you or the technician to easily determine the issue. This can save time, trouble shooting guess work and costly unnecessary repair calls as often simple issues can be resolved with a phone call.