It’s surprisingly simple how a heating system works in your Arlington, Fort Worth, or Dallas home.
In a previous post we established a baseline understanding of home heating systems, particularly how they are rated for energy efficiency, which is important for troubleshooting performance issues and knowing when to call a service or repair tech to discuss retrofitting or purchasing new equipment.
Now we examine how your home heating system works.
It’s surprisingly simple:
- The heating system takes in cold air.
- It cleans it with an air filter.
- It heats it with a gas burner and a steel heat exchanger.
- It distributes the warm air via a blower motor through the ductwork into the home.
- Bingo. Once the heated air cools in various rooms, it returns to the furnace through return air vents and ductwork.
The next time a contractor from an Arlington, Fort Worth, or Dallas company sends out a service or repair tech for a winter (or spring) checkup, ask him to take you on a quick tour of the process.
Draft Inducer Fan
Modern furnaces rely on a fan to create a draft up the chimney, rather than heat produced by a roaring flame from the burner.
Ignitor, Gas Valve
This creates a high-voltage spark or glows red hot to ignite the rush of gas to the burner. Its electromagnet is energized and opens to permit gas flow after it receives a signal, which happens after the thermostat and all other controls are energized.
There are no moving parts. Just the burner, with a row of tubes, that allow fuel and air to mix at the proper ratio so they can burn at the highest efficiency possible. That’s important for energy conservation and controlling costs.
The principle is simple. Heat the metal plate with a gas flame and pass air over it. The heated air is then distributed to the house and the flue gas, or waste, goes out the chimney.
A fan creates pressure inside the furnace so the cool air is pulled in to be heated and the warm air produced is pushed into the ducts for distribution. Modern forced-air systems are far superior to old gravity heating.
Once warm air cools, it returns through a series of ducts and the process begins again. If return air ducts are insufficient, the house can become slightly pressurized and heated or cooled air is driven out and energy is wasted.
Obviously, you will want an Arlington, Fort Worth, or Dallas contractor to send service or repair technicians to your home, ideally at the start of the winter, to inspect the components and performance of the heating system.
It’s best to keep tabs on the overall condition of the equipment, which is why heating, ventilation, and air conditioning (HVAC) service and repair professionals and manufacturers recommend twice-a-year service checkups to start the winter and summer heating and cooling seasons.
Conventional Furnaces vs. High Efficiency
Now that you know the basic operation of a home heating system, it’s time to understand the differences between conventional and high-efficiency furnaces.
First older gas furnaces use a pilot light (images) as an ignition source. A regulator supplies a small flow of gas to keep a short flame burning so it would be ready to ignite the gas when it was time to heat the home.
More modern and efficient furnaces use a “glow stick” (images) made of silicone nitride as an ignition source. Electricity passes a current through the glow stick when the furnace calls for heat.
Standard Gas Furnaces
Standard gas furnaces rely on natural gas or propane as the energy source for generating heat. When the temperature in the home falls below the set point on the thermostat (68 degrees, for example), the electric pilot light (images) automatically ignites to begin the heating process.
The burner (images) utilizes the gas to generate heat within a combustion chamber (images) inside the furnace. This heat passes into a heat exchanger (images). When a fan (images) blows air onto the heat exchanger, it is heated and the warm air is blown through a series of ducts (images) into the home. Exhaust fumes from the combustion process exit through a gas flue or chimney (images).
High Efficiency Furnaces
High efficiency furnaces (images, diagrams) function the same but use a second combustion chamber, which captures exhaust gases and moisture before it exits into the flue.
The second chamber condenses the gaseous by-product to form a liquid, then extracts any remaining heat, which is then transferred into a second heat exchanger. That heat supplements the primary heat exchanger for additional warmth.
What little waste remaining is exhausted through a small flue or pipe, making the entire heating process much more energy efficient.
When considering retrofitting or replacing heating equipment, it’s well worth talking with a service or repair tech in the Arlington, Fort Worth, and Dallas area about the advantages and cost of a high efficiency system over standard furnaces.
High-Efficiency furnaces will have significant impact on a home’s energy consumption. According to Energy Savers, homeowners who switch from an older furnace with a 56 percent AFUE (annual fuel utilization efficiency) rating to a 90 percent rating can reduce annual carbon dioxide emissions by as much as 1.5 tons per home.
As expected, higher-efficiency gas furnaces cost more than standard models, but they will be more economical over time, especially if you are upgrading from a low AFUE-rated product.
The American Council for an Energy Efficient Economy (ACEEE) estimates that homeowners can save $27 for each $100 they currently spend in fuel by updating from a 60 AFUE furnace to 95 percent AFUE.
According to Energy Star and the U.S. Department of Energy, homeowners who buy a gas furnace with a 95 percent AFUE can receive up to $1,500 in federal tax credits, although this varies. Check with trusted service and repair techs in the Arlington, Fort Worth, and Dallas area, who, if they are good as they say they are, they should already be aware of incentives.
Here’s another way to look at standard vs. high efficiency: Even if your furnace is rated at 80 percent AFUE and it produces a monthly gas bill of $279, about $56 of that bill has fueled nothing. It’s wasted heat that has gone up the chimney and wasted money..
Next up: troubleshooting your heating system before calling that Arlington, Fort Worth, or Dallas contractor.