Modern gas furnaces use electrical ignition instead of a pilot light. HVAC manufacturers switched away from pilots because they are slightly dangerous, waste gas, and cause service calls when they go out. The average Denver furnace services company will re-light your furnace for free, but this is not a call they want to go on.

 Electrical ignition is divided into three types. Usually electronically ignited furnaces are more efficient because they are newer and more care went into their design. One type of ignition is the intermittent spark pilot. The system basically just takes sea normal spark pilot ignition system and links it with the thermostat. When the thermostat calls for heat, first the electronic igniter lights the pilot, then furnace operation works normally from there. Once heat is no longer needed, the furnace and pilot stop.

 Intermittent hot surface ignition was invented by Honeywell, the masters of pilots and thermostats. Instead of a spark, the system uses a hot loop of wire and electronic sensors to see if the pilot is lit. The sensor is built into the central heating units digital controls.

Intermittent hot surface ignition was invented by Honeywell, the masters of pilots and thermostats. Instead of a spark, the system uses a hot loop of wire and electronic sensors to see if the pilot is lit. The sensor is built into the central heating units digital controls.

There is an ignition type called hot surface furnace ignition which bypasses the pilot step and lights the burners directly. Sometimes called direct ignition, the igniter consists of a red hot wire above the burner. Once it reaches a certain temperature the gas turns on, the gas ignites and once the solid state controls confirm this, the power to the igniter turns off.

Combining these advanced ignition controls with efficient heat exchangers can result in efficiency increases of more than 50% compared to older furnaces with a standing pilot. Burning a pilot flame for weeks without using it is simply a waste. Efficiency is often rated by percent. So an older burner that achieves 70% efficiency, 70% of the energy burned goes into the home and the rest is absorbed into the atmosphere.

A more efficient furnace actually burns cooler. This is because less energy is needed to heat the house. This venting creates a problem for Denver HVAC contractors because all that vented gas cools and deposits moisture. So sometimes the vent needs a drain, which may be combined with the air conditioning condenser moisture. Having a induction draft fan to blow air through the furnace can help with this problem and increase efficiency in several ways. Draft motors make the burning more efficient just like a supercharger in a car, and also exhaust gases fast enough to help venting problems.