When the temperature drops below a certain point, it can cause your heating system’s auxiliary heat to turn on, but what is auxiliary heat and what purpose does it serve? To put it simply, auxiliary heat is a secondary heating system that kicks in whenever your heat pump’s efficiency drops, allowing it to keep your home warm despite the frigid outdoor weather.
At Lex Air Conditioning and Heating, our HVAC technicians are well-equipped to handle a variety of auxiliary heating system needs for a range of different types of heat pumps. Whether you’re experiencing frequent auxiliary heat activation, suspect issues with your backup heating, or simply want to optimize your HVAC system’s performance during colder months, our Carrollton heating technicians are here to help.
To learn more, contact Lex Air today at (972) 217-8955 to schedule a consultation with our knowledgeable HVAC technicians.
What Does Aux Mean on Thermostat?
“Aux” on a thermostat stands for auxiliary heat, which acts as a backup heating system when the primary heat pump system can’t keep up with the demand for heat. This is especially helpful in colder weather, acting as a secondary heat source to increase the heat pump’s efficiency.
When the aux heat indicator is displayed on your thermostat, your system is using an electric or gas backup heater to help maintain your desired temperature.
Aux Heat vs. Heat
Auxiliary heat is often used in conjunction with a heat pump. It kicks in when the heat pump alone can’t generate enough heat to maintain a comfortable indoor temperature due to very cold outdoor temperatures. It typically involves electric resistance heating strips or a backup furnace to supplement warmth.
Regular heat, provided by the heat pump itself, is more energy-efficient and is used during most of the winter. However, your HVAC system’s primary heating may struggle in extreme cold, prompting the auxiliary heat cycle to kick on and generate additional heat.
Types of Auxiliary Heat Sources
Auxiliary heat sources typically include electric resistance heating, gas furnaces, or oil furnaces. Electric resistance heating is the most common, using electric coils to generate heat when the heat pump alone can’t generate enough heat to maintain the desired temperature.
Gas and oil furnaces are less common but provide an efficient backup in systems designed to switch between the heat pump and a furnace. Each type has different operating costs and efficiency levels, with electric heating usually being more expensive than gas or oil.
Is Auxiliary Heat the Same as Emergency Heat?
Auxiliary heat and emergency heat are not the same, though they both involve backup heating. Auxiliary heat mode automatically kicks in when the heat pump can’t meet the demand for warmth, usually due to cold weather.
Emergency heat mode, on the other hand, is manually activated by the homeowner when the heat pump malfunctions or is unable to work at all, relying entirely on the backup system for heat.
Why Does Auxiliary Heat Come On?
In general, a heat pump can extract heat from the outside air (even extremely cold air) and transfer it indoors using refrigerant. However, as outdoor temperatures drop, the amount of available heat decreases, making it harder for the heat pump to maintain the desired indoor temperature.
The heat pump may struggle to transfer heat indoors, leading to reduced heating output and potentially causing indoor temperatures to drop. In response, the thermostat activates the auxiliary heat source, which can be electric resistance coils or a backup furnace, providing additional warmth to quickly restore comfort.
This auxiliary heating mechanism ensures that homes remain warm during particularly cold spells when the primary heat pump system cannot operate efficiently.
How To Know if Your Auxiliary Heat is On
You can tell if your auxiliary heat is on by checking your thermostat display, which will usually show “Aux” or “Auxiliary Heat” when the system is running. Additionally, you might notice that your HVAC system runs longer or your home’s energy usage increases since auxiliary heat typically consumes more power than the heat pump.
Some systems may also produce warmer air when the auxiliary heat strip inside your heat pump is energized. It may also begin to smell like something is burning, especially if you haven’t used this secondary heating source in a while. Dust can accumulate on the heating coils, and when the auxiliary heat kicks in, the coils burn off that dust, producing a noticeable odor.
What Temperature Should Auxiliary Heat Come On?
Auxiliary heat typically comes on when outdoor temperatures drop below 35-40°F, as the heat pump becomes less efficient in colder weather. The exact temperature can vary based on your system settings and home insulation, but it usually activates when the heat pump can’t maintain the desired indoor temperature on its own.
Some systems also trigger auxiliary heat if there’s a significant temperature difference between your thermostat’s set temperature and the current temperature inside your home. For example, if your thermostat is set to 64°F and the room temperature is 58°F, then the aux heat may activate to bring the temperature up those last few degrees.
Aux heat can also come on if your heat pump is in defrost mode, which temporarily shuts off the regular heating function to clear ice from the outdoor unit.
Does Emergency Heat Come on Automatically?
No, emergency heat does not come on automatically. It must be manually activated by switching the thermostat to the “Emergency Heat” setting. This is typically done when the heat pump is malfunctioning or unable to operate, and the system relies entirely on the backup heating source to provide warmth.
Unlike auxiliary heat, which turns on automatically due to extremely cold outdoor temperatures, emergency heat is used only in situations where the heat pump cannot function.
Is it Bad if the Auxiliary Heat Comes On?
While many people may avoid using auxiliary heat, is it bad if auxiliary heat turns on? No, it’s not bad if the auxiliary heat comes on; it’s designed to provide extra warmth when needed, especially in very cold weather.
However, auxiliary heat mode can use more energy than regular heat mode, and frequent or prolonged use can increase your utility bills. Additionally, if it comes on often during mild weather, it could indicate an issue with your heat pump or thermostat that may need attention.
Common Issues with Auxiliary Heat
Common issues with auxiliary heat include it staying on too long or activating too frequently, which can lead to higher energy bills. This could be due to a malfunctioning thermostat, improper heat pump settings, or an issue with the outdoor temperature sensor.
Additionally, if auxiliary heat doesn’t turn on at all during cold weather, there could be a problem with the backup heating system itself, such as faulty heating coils or a malfunctioning furnace. Regular maintenance can help prevent these issues.
If you believe you’re experiencing issues with your system’s thermostat, schedule Carrollton thermostat services from the experienced professionals at Lex Air Conditioning and Heating. We can evaluate the extent of the damage and repair any issues to ensure that your heating system only runs on auxiliary heat when necessary.
Tips for Reducing Auxiliary Heat Use
Reducing the use of auxiliary heat can help lower energy costs while ensuring your home stays comfortable during colder weather. Here are some tips to stop auxiliary heat from coming on or minimize auxiliary heat usage overall:
- Improve insulation in your home to retain heat better, reducing the need for auxiliary heat.
- Set your thermostat to gradually adjust temperatures during the day to reduce the need for sudden auxiliary heat activation.
- Seal windows, doors, and ductwork to prevent heat loss, helping your heat pump maintain indoor temperatures more effectively.
- Adjust your heat pump settings according to manufacturer recommendations and local climate conditions.
- Frequent changes in thermostat settings can lead to auxiliary heat activation unnecessarily.
- Keep outdoor units clear of debris and snow to ensure optimal heat pump performance in colder temperatures.
- Sign up for our annual HVAC maintenance plan to ensure your heat pump and auxiliary heating systems are working efficiently.
Reducing auxiliary heat usage not only saves energy but also extends the lifespan of your HVAC system. By implementing these tips, you can achieve greater efficiency and comfort throughout the heating season.
How a Professional Carrollton HVAC Technician From Lex Air Can Help
When it comes to your home’s heating needs, the Carrollton heating repair professionals at Lex Air Conditioning and Heating have you covered. Our skilled HVAC professionals are trained to handle a wide range of heating system issues, from routine maintenance to complex repairs.
Whether you’re looking to optimize your heat pump, troubleshoot auxiliary problems, or ensure your HVAC unit operates smoothly throughout the heating season, our experts are here to help.
Our technicians not only diagnose and fix issues promptly but also provide valuable advice on improving energy efficiency and prolonging the lifespan of your HVAC equipment.
Don’t get left out in the cold–call (972) 217-8955 or contact us online to schedule repairs with us today!
