Heating Systems, Furnaces and Heating Repair
Your furnace is no different than any other major appliance in your house, other than it is permanently installed. With regular service you will keep the heating repair to your St. Louis home or business to a minimum and your heating system will provide heat to the interior spaces of your home or other work areas through a series of pipes, referred to as duct work. Modern heating systems are known as “forced air” systems since a fan inside the furnace is used to force air through the duct work and into the different rooms in your house. Most furnaces in the United States including St. Louis, St. Charles and Warren County use natural gas as their fuel, but other common fuels include liquefied petroleum gas (LPG), coal, fuel oil and wood. Furnaces powered by electricity are also common. Every type of heating system is subject to failures which could result in heating repair being necessary.
All types of furnaces except electric need to be vented to the outside. Generally you will see this as a pipe running out through your roof and in the winter time you may see smoke or steam rising from it. Some modern high-efficiency furnaces can run at efficiencies as high as 98% and can be vented out through a small tube to the outside of the house. Furnaces with efficiencies greater than about 89% must be designed to avoid the corrosion that can occur due to their condensing of water vapor in the exhaust. Some modern high-efficiency furnaces can deliver heating savings of up to 35%, assuming the old furnace was in the 60% (typical of older furnaces) Annual Fuel Utilization Efficiency (AFUE) range. 
Variable Speed Gas Furnaces
Variable speed natural gas heating furnaces typically operate at two different speeds. Under most circumstances the furnace will operate continuously at a lower speed. This prevents the up and down temperature swings common in older forced air furnace systems, helping to keep your home comfortable at a steady temperature. When necessary, the furnace will operate at maximum speed to meet an immediate demand, for instance when you first turn it on. Variable speed furnaces range in efficiency from about 80 to 95% AFUE. The minimum government AFUE efficiency requirement is 78%. Make sure you ask about the warranty, as different parts of the furnace can have different warranties. A good heating systems furnace for St. Louis and elsewhere will come with a limited lifetime warranty on the heat exchanger. Additional benefits of a variable speed furnace include more efficient use of the air filtration system and quieter system operation. Lennox®variable speed gas furnaces
Gas Furnaces
Traditional forced air gas furnaces operate at a single speed. The furnace turns on when needed and off when the room reaches the desired temperature. There is some variation of temperature in the room as the furnace runs through it's cycle, but usually not enough to be very noticeable. Gas furnaces can vary in efficiency from about 80 to 95% AFUE. The minimum government AFUE efficiency requirement is 78%. Make sure you ask about the warranty, as different parts of the furnace can have different warranties. A good furnace will come with a limited lifetime warranty on the heat exchanger. Lennox® gas furnaces
Oil Furnaces
Oil furnaces operate on fuel oil and are generally not as efficient as gas furnaces. but they can actually last longer and require less heating repair They are particularly useful in areas where a source of natural gas is not readily accessible. Oil furnaces generally operate at efficiency ratings in the low to mid-80% AFUE range. Depending on the particular oil furnace, some can operate at variable speeds and some operate at a single speed. You are more likely to encounter oil furnaces in rural areas outside of cities like St. Louis. Lennox® oil furnaces