If you've noticed "auxiliary heat" or "aux heat" pop up on your thermostat during those rare chilly South Bay mornings, you're probably wondering what it means, and more importantly, what it's costing you.
Here's the quick answer: Auxiliary heat refers to the electric heat strips built into your heat pump's air handler. When your heat pump can't maintain your desired temperature on its own, these backup heat strips kick in automatically to keep your home comfortable.
Think of it as your heating system's safety net. Your heat pump handles most of the heavy lifting, but when conditions get tough, the auxiliary heat steps in to bridge the gap.
Why Your Heat Pump Has Auxiliary Heat
Here in the South Bay, we're spoiled with near-perfect weather. But even our mild winters occasionally dip into the 40s and 30s overnight, especially in areas like Torrance, Redondo Beach, and Manhattan Beach. When that happens, your heat pump needs a little help.
Heat pumps work by extracting warmth from outdoor air and transferring it inside. It's an incredibly efficient process that works beautifully in our climate. But here's the thing: as outdoor temperatures drop, there's less heat energy available to extract. When your thermostat says auxiliary heat, it means your system has determined it needs backup support.
When Does Aux Heat Come On?
Your heat pump auxiliary heat typically activates in two scenarios:
1. Cold weather conditions
When outdoor temperatures fall below about 35-40°F, your heat pump starts working harder to extract heat from the air. If it can't keep up with your thermostat setting, the auxiliary heat automatically engages. For South Bay residents, this usually only happens during those occasional cold snaps we get between December and February.
2. Rapid temperature increases
An example of this is if you've been away for a long weekend and set your thermostat down to 62°F to save energy, which is a smart move. But now you're home and crank it up to 72°F all at once. Your heat pump can't raise the temperature 10 degrees that quickly on its own, so auxiliary heat kicks in to speed things up.
What's the Difference Between Auxiliary Heat and Emergency Heat?
This is one of the most common questions people can ask, and it's an important distinction.
Auxiliary heat comes on automatically whenever your system needs it. You don't control it; your thermostat does. It's a normal part of heat pump operation.
Emergency heat is a manual setting you control. When you switch your thermostat to "emergency heat" or "EM heat," you're telling the system to use only the electric heat strips and bypass the heat pump.
Think of emergency heat mode as a backup plan for when your heat pump isn't working properly. If you hear unusual noises, notice ice buildup on your outdoor unit, or suspect your heat pump has stopped functioning, that's when you'd manually switch to emergency heat and call us for service.
The key difference? Auxiliary heat vs emergency heat comes down to automatic versus manual control. Auxiliary heat works alongside your heat pump, and emergency heat replaces it entirely.
The Real Cost: Does Aux Heat Cost More?
Let's talk about what people care about when it comes to heating, your utility bill.
Yes, auxiliary heat is significantly more expensive to operate than your standard heat pump. Electric heat strips are essentially large resistive heating elements, similar to the coils in a toaster. They're 100% efficient at converting electricity to heat, but they use a lot of power to do it.
Why are heat strips so expensive?
Your heat pump can move 3-4 times as much heat energy as it consumes in electricity. That's called the coefficient of performance (COP), and it's what makes heat pumps so efficient. Electric heat strips, on the other hand, have a COP of exactly 1.0; you get one unit of heat for every unit of electricity used.
Here in the South Bay, electricity rates are among the highest in the nation, and running auxiliary heat even occasionally can noticeably impact your bill. That's why understanding when and why it activates is so important.
How to Minimize Auxiliary Heat Usage in Your South Bay Home
Nobody wants to see their energy costs spike, especially when Southern California Edison rates keep climbing. Here are practical ways to reduce how often your auxiliary heat runs:
1. Keep Your Thermostat Steady
The biggest trigger for auxiliary heat (besides cold weather) is rapid temperature changes. Instead of cranking your thermostat up by 8-10 degrees all at once, try raising it gradually, 2 degrees at a time. Give your heat pump 20-30 minutes to reach that temperature before bumping it up again.
Your heat pump is perfectly capable of maintaining comfortable temperatures. It just struggles with sudden, large temperature swings.
2. Use Programmable Settings Wisely
If you're leaving home for an extended period, don't drop your thermostat too low. Setting it to 65°F instead of 60°F won't cost you much more while you're away, but it'll save you from triggering auxiliary heat when you return and bump it back up.
Many modern thermostats even have settings that limit how quickly the temperature can change, specifically to prevent unnecessary activation of auxiliary heat.
3. Maintain Your System Regularly
A well-maintained heat pump runs more efficiently and can handle lower temperatures before needing backup heat. At Total Home Environmental, our comprehensive maintenance includes:
- Cleaning or replacing air filters
- Checking refrigerant levels
- Inspecting electrical connections
- Testing thermostat calibration
- Ensuring proper airflow
When your system is running optimally, it can handle a greater share of the heating load on its own, reducing reliance on those expensive heat strips.
4. Consider Your Temperature Preferences
This might not be what you want to hear, but keeping your thermostat in the mid-to-high 60s rather than the low 70s significantly reduces your heating load. In the South Bay's mild climate, many of our customers find 68°F perfectly comfortable during winter days.
Every degree you lower your thermostat reduces your heating costs by about 1-3%. Combined with minimizing auxiliary heat usage, that can add up to real savings.
Is Your Heat Pump Struggling More Than It Should?
While it's normal for auxiliary heat to activate occasionally during cold weather, frequent or prolonged use might indicate a problem. Here are signs your heat pump backup heat system needs professional attention:
- Auxiliary heat runs constantly even in moderate temperatures (above 45°F)
- Your utility bills have spiked dramatically without explanation
- The system struggles to reach your set temperature, even with auxiliary heat running
- You notice ice buildup on your outdoor heat pump unit
- Strange noises come from your indoor or outdoor equipment
These symptoms could indicate issues such as low refrigerant levels, a failing compressor, blocked airflow, or a malfunctioning thermostat. Don't ignore them; what starts as reduced efficiency can quickly become a complete system failure.
The South Bay Advantage: Why Heat Pumps Work So Well Here
Let's put this in perspective. If you lived in Atlanta or Boston, auxiliary heat would be a much bigger concern, but here in the South Bay, we're in the sweet spot for heat pump efficiency.
Our coastal climate means:
- Mild winters with average lows rarely dropping below 45°F
- Moderate summers that don't stress your system
- Year-round efficiency that makes heat pumps one of the most cost-effective options
- Minimal auxiliary heat usage compared to colder climates
At Total Home Environmental, we've been serving Torrance, Redondo Beach, Manhattan Beach, Hermosa Beach, and the surrounding South Bay communities for years. We've seen firsthand how well heat pumps perform in our microclimate, even with the occasional need for auxiliary heat.
Modern Heat Pumps: Better Than Ever
If your heat pump seems to need auxiliary heat more often than you'd like, there's good news. Today's heat pump technology has improved dramatically over the past decade.
Modern cold-climate heat pumps can operate efficiently at much lower temperatures than older models. Some systems maintain high efficiency down to 5°F or even lower, though we rarely see those temperatures in the South Bay!
When it's time to replace your system, you have options that minimize auxiliary heat usage:
- Variable-speed heat pumps adjust their output to match your exact heating needs, reducing the need for supplemental heat.
- Dual-fuel systems pair a heat pump with a gas furnace (if you have gas lines), automatically switching to the most efficient heat source based on outdoor temperature.
- Enhanced cold-weather models use advanced refrigerants and compressor technology to extract heat more effectively from cold air.
At Total Home Environmental, we help South Bay homeowners select the right system for their specific needs and budget. Our team considers factors like your home's size, insulation, ductwork condition, and typical temperature preferences to recommend the most efficient solution.
Should You Worry When the Thermostat Says Aux Heat?
Short answer: Probably not, as long as it's occasional and brief.
Seeing "aux heat" on your thermostat during a cold morning or after adjusting your temperature significantly is completely normal. Your system is doing exactly what it's designed to do: keeping you comfortable.
However, if you notice auxiliary heat running frequently or for extended periods, that's worth investigating. A quick diagnostic from our certified technicians can identify whether it's normal operation for the conditions or if there's an underlying issue affecting your system's efficiency.
Heat Pump Service and Repair in Torrance and the South Bay
At Total Home Environmental, we understand heat pumps inside and out. As a family-owned company serving Torrance and the Greater South Bay, we've helped countless homeowners optimize their heat pump performance and minimize costly auxiliary heat usage.
Whether you're concerned about why your aux heat keeps coming on, need routine maintenance to keep your system running efficiently, or you're ready to upgrade to a more efficient model, we're here to help.
Our Services Include:
- 24/7 Emergency HVAC Service - Because heating issues don't wait for business hours
- Comprehensive Heat Pump Maintenance - Keep your system running efficiently year-round
- System Diagnostics and Repair - Fast, accurate troubleshooting from certified technicians
- Heat Pump Installation and Replacement - Expert recommendations and professional installation
- Thermostat Upgrades - Modern thermostats with smarter auxiliary heat management
We offer same-day service with no trip fees when we complete your repair. Plus, we provide a lifetime warranty on all repairs we perform; that's how confident we are in our work.
Serving Your South Bay Neighborhood
Our Torrance-based team is just minutes away from homes throughout:
We know the unique challenges South Bay homeowners face, from coastal humidity to fluctuating temperatures. Our solutions are tailored specifically for our local climate and your home's needs.
Questions About Auxiliary Heat? We Have Answers.
Understanding your heat pump system doesn't have to be complicated. If you're seeing auxiliary heat more often than expected, have questions about your utility bills, or simply want to ensure your system is running as efficiently as possible, give us a call.
At Total Home Environmental, we don't just fix HVAC systems; we educate our customers so they can make informed decisions about their home comfort. Our factory-trained technicians will take the time to explain what's happening with your system and provide honest recommendations.
Ready to optimize your heat pump performance? Contact Total Home Environmental for expert service throughout the South Bay. We're available 7 days a week to keep your home comfortable and your energy bills manageable.