Central Florida may be known for sunshine and warmth, but residents of Ocala, The Villages, and surrounding areas know that winter can bring surprisingly cold temperatures. When a cold snap hits and you see “AUX” or “EM Heat” on your thermostat, you might wonder what these settings mean. At United Refrigeration, with over 40 years of experience and a 4.9-star rating from hundreds of satisfied customers, we’ve helped countless homeowners understand their heat pump systems. Let’s clear up the confusion and help you use your system efficiently.
Understanding Your Heat Pump System
Heat pumps work by transferring heat rather than generating it. During Florida’s mild winters, your heat pump pulls warmth from outdoor air and moves it inside. This process is remarkably efficient, even when temperatures drop into the 40s or 50s.
However, when outdoor temperatures drop below about 35 degrees Fahrenheit, your heat pump may struggle to produce enough heat. This is where backup heating comes into play.
What is Auxiliary Heat?
Auxiliary heat automatically activates when there isn’t enough heat outdoors for the heat pump to maintain your desired temperature comfortably.
How It Works
When your thermostat senses that your home’s temperature has fallen several degrees below your set point (typically 3 degrees or more), it automatically engages auxiliary heat while the heat pump continues to run. You’ll see “AUX” light up on your thermostat.
This supplemental heat, also called second-stage or backup heating, comes from electric resistance heating coils in your indoor air handler, with first-stage being the heat pump only.
When It Activates
In Central Florida, auxiliary heat typically kicks in during:
- Cold snaps when temperatures dip into the 30s or 40s
- Early morning hours when outdoor temperatures are coldest
- Times when you’ve significantly raised your thermostat setting
- Periods when your home is struggling to reach the desired temperature
This is completely normal and nothing to worry about. The system is designed to work this way.
What is Emergency Heat?
Emergency Heat also refers to electric resistance heating, but there’s a critical difference: it’s manually activated and shuts down your heat pump completely.
The Key Difference
When you manually switch to emergency heat mode, your outdoor heat pump shuts down completely, and your system relies solely on the electric resistance heating coils. You’re using your supplemental heat (2nd stage) by itself, without the heat pump (1st stage).
When to Use Emergency Heat
As the name implies, emergency heat is for emergency situations only:
Heat Pump Malfunction If your heat pump is malfunctioning and you need to keep your house warm while waiting for repairs, emergency heat keeps you comfortable until United Refrigeration can send a technician.
Physical Damage to Outdoor Unit If a storm damages your outdoor unit, emergency heat allows you to maintain warmth while waiting for repairs.
Severe Ice Buildup In rare cases during freezing rain, ice could build up and potentially damage your equipment. Emergency heat mode can prevent further damage.
Common Misconceptions About Emergency Heat
Myth: Use Emergency Heat When It’s Really Cold
This outdated advice applied to old, inefficient heat pumps from decades ago. Modern systems are much better equipped to handle colder weather and remain efficient even below freezing.
Your heat pump will automatically engage auxiliary heat when needed. There’s no reason to manually switch to emergency heat just because it’s cold outside.
Myth: Emergency Heat Works Better
Emergency heat doesn’t heat your home any better than your heat pump with auxiliary heat working together. In fact, heat pumps remain very efficient at heating (around $0.02–$0.05 per 1,000 BTUs) even at low temperatures, while electric resistance heat is significantly more costly (around $0.12 per 1,000 BTUs).
The Cost of Emergency Heat
Using emergency heat unnecessarily can dramatically increase your energy bills. Electric resistance heaters are only 100% efficient—one unit of energy equals one unit of heat.
Heat pumps can be 200-300% efficient because they’re moving heat rather than generating it. For every unit of electricity consumed, they produce two to three units of heat.
What to Do When You See “AUX” on Your Thermostat
When you notice the auxiliary heat indicator during a cold Central Florida morning:
- Don’t panic – This is completely normal
- Don’t manually switch to emergency heat – Your system is working as designed
- Monitor your home’s temperature – If it’s reaching the set temperature, everything is fine
- Check your outdoor unit – Make sure it’s running and not frozen over
- Call United Refrigeration if concerned – Our 4.9-star rated team is always here to help
Signs Your Heat Pump Needs Professional Attention
While auxiliary heat cycling during cold weather is normal, certain signs indicate a problem:
- Your home never reaches the set temperature, even with auxiliary heat running
- The auxiliary or emergency heat indicator stays on constantly
- You hear unusual noises from your outdoor unit
- You see excessive ice buildup on the outdoor unit
- Your energy bills have suddenly skyrocketed
- The outdoor unit isn’t running at all
If you notice any of these issues, call United Refrigeration. With hundreds of five-star reviews and over 40 years serving Central Florida, our technicians diagnose and repair heat pump problems quickly.
Preventing Cold Weather Heat Pump Problems
Schedule Preventive Maintenance
Regular maintenance keeps your heat pump operating efficiently during cold Central Florida mornings. Our comprehensive tune-ups include checking refrigerant levels, cleaning coils, inspecting electrical connections, testing defrost controls, and calibrating thermostat settings.
Keep Your Outdoor Unit Clear
Ensure the area around your heat pump is free from fallen leaves, debris, overgrown vegetation, and stored items.
Replace Air Filters Regularly
Dirty filters restrict airflow, making your system work harder and potentially triggering excessive auxiliary heat use. Check filters monthly and replace as needed.
Why Central Florida Trusts United Refrigeration
Our 4.9-star Google rating from hundreds of customers reflects our commitment to exceptional service. When you call us with heating concerns, expect:
- Fast Response Times: Heat pump problems during cold weather can’t wait
- Expert Diagnosis: Our technicians have seen every heat pump issue imaginable
- Honest Recommendations: We’ll never tell you to use emergency heat when you don’t need it
- 24/7 Emergency Service: Cold weather doesn’t follow business hours
- Over 40 Years of Experience: We’ve been serving Central Florida for decades
The Bottom Line
Understanding the difference between auxiliary heat and emergency heat saves you money and prevents unnecessary worry:
- Auxiliary heat is automatic and normal – Let your system do its job
- Emergency heat is manual and for emergencies only – Use only when your heat pump isn’t working
- Modern heat pumps handle Florida winters well – They don’t need emergency heat just because it’s cold
- Professional maintenance prevents problems – Regular service keeps your system running efficiently
Stay Comfortable This Winter
Don’t let confusion about emergency heat settings leave you uncomfortable or facing high energy bills. The experienced team at United Refrigeration ensures your heat pump system keeps you comfortable all winter long.
If you’re unsure whether your heat pump is operating correctly, or if you’d like to schedule preventive maintenance before winter weather arrives, contact United Refrigeration today. Our hundreds of five-star reviews speak to our commitment to keeping Central Florida homes comfortable, efficient, and worry-free.
Contact United Refrigeration
- Website: https://unitedairheat.com/
- Google Reviews: 4.9 stars from hundreds of satisfied customers
- Emergency Service: Available 24/7
- Service Areas: Ocala, The Villages, and all of Central Florida
- Services: Heat pump maintenance, repair, installation, and expert advice
