Furnaces
A furnace is a heating appliance used primarily in homes and buildings to provide warmth by heating air, which is then circulated through ductwork to the rest of the space. (Equipment that heats water instead is a boiler.) Furnaces are central to many HVAC systems, including in mixed climates like Oklahoma where a hot summer is still followed by a genuine heating season.
## Furnaces in an Oklahoma Winter
Oklahoma gives a furnace a real heating season and then a punishing cooling season on the same equipment, so nothing here gets an off-season. The federal minimum for new gas furnaces is 80% AFUE, and an 80% unit is often a sound choice in a climate where heating is not the dominant half of the yearly bill — the payback on a condensing model depends on how many hours the furnace actually runs. Fuel availability matters more than the rating for many properties: rural McClain, Grady and Garvin County homes are commonly on propane rather than city gas, which needs different burner orifices and gas pressure than a natural-gas setup. Red-dirt dust also loads filters and blower wheels faster than in most climates, so airflow is worth checking before booking a furnace repair. Ice storms and hard cold snaps still arrive, whatever the summer looked like.
Most of the no-heat calls our techs run in a cold snap come down to airflow or ignition — a clogged filter or a dirty flame sensor will shut a furnace down long before the heat exchanger is the problem.
If your furnace has not been looked at since last winter, a furnace tune-up covers the combustion, safety and airflow checks before the first hard freeze — our $95 diagnostic is waived if you approve the repair on that visit (pricing).
Types of Furnaces
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Gas Furnaces:
- Natural Gas: Most common, using natural gas as fuel for heating.
- Propane: Similar to natural gas but used in areas where natural gas isn't available.
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Oil Furnaces: Use heating oil, often in regions where natural gas isn't accessible.
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Electric Furnaces: Convert electrical energy into heat, typically via resistance heating elements.
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Dual Fuel: Combines gas or oil with an electric heat pump for higher efficiency across different weather conditions.
How Furnaces Work
- Heat Generation: Fuel (gas, oil, or electricity) is burned or converted into heat within the furnace.
- Heat Distribution: The generated heat warms the air, which is then circulated via ductwork to different areas of the building.
- Air Handling: A blower fan moves the heated air through the supply ducts and pulls return air back over the heat exchanger.
Efficiency Measures
- AFUE (Annual Fuel Utilization Efficiency): A measure of how efficiently a furnace converts fuel to heat. Higher percentages indicate better efficiency.
- Standard Efficiency: Typically 80-89% AFUE.
- High-Efficiency: 90% AFUE or higher, often with condensing technology to capture more heat from combustion gases.
Maintenance and Longevity
- Regular Check-ups: Annual inspections to ensure safe operation, efficiency, and to prevent breakdowns.
- Filter Maintenance: Regular replacement or cleaning of filters to maintain air quality and furnace efficiency.
- Duct Cleaning: Occasionally, ducts should be checked and cleaned to optimize airflow.
Choosing a Furnace
- Size: The furnace should match the heating load of the space, calculated through a load calculation.
- Efficiency: Consider the AFUE rating but also look at overall system efficiency, including ductwork.
- Fuel Availability: Depending on your location, you might not have access to all types of fuel.
- Installation Costs vs. Operational Savings: High-efficiency models might cost more upfront but save on energy bills over time.
Environmental Considerations
- Emissions: Gas and oil furnaces emit greenhouse gases, though high-efficiency models produce less.
- Electric: Can be more environmentally friendly if the electricity comes from renewable sources.
Conclusion
Furnaces are fundamental for providing warmth in many homes, with various types to suit different needs, climates, and infrastructures. Understanding furnace types, how they operate, and their efficiency can lead to better choices for comfort, cost-efficiency, and environmental impact.