If you’ve ever glanced at your thermostat and noticed the words “auxiliary heat,” you’re not alone in wondering what’s going on.

A lot of homeowners search “why is my aux heat on” the moment they see that light pop up. It sounds serious. Sometimes it even feels like something’s wrong. But here’s the thing. Auxiliary heat is often doing exactly what it’s designed to do, and there’s probably no need to worry. 

Let’s break down what auxiliary heat actually means, when it should turn on, and when it might signal a heating troubleshooting issue.

What Is Auxiliary Heat?

Auxiliary heat is a secondary heating system that works alongside your heat pump.

Most heat pumps pull warmth from the outside air, even when it’s cold. But when outdoor temperatures drop too low, your heat pump may need backup support. That backup is your auxiliary heat.

In most systems, this comes from electric resistance heat strips inside the air handler.

Think of it as your system’s safety net.

When Should Auxiliary Heat Turn On?

In a properly working system, auxiliary heat turns on under specific conditions:

• Very cold outdoor temperatures: When the heat pump can’t extract enough warmth from the air.
• Large temperature adjustments: If you raise your thermostat several degrees at once.
• Defrost mode: When the heat pump temporarily switches to cooling mode to melt ice buildup.

During these situations, auxiliary heat helps your home maintain a comfortable indoor temperature.

In colder climates, it may come on fairly often. In milder regions, it may only run during occasional cold snaps.

Why Is My Aux Heat On When It’s Not That Cold?

This is one of the most common heating troubleshooting questions homeowners ask.

If your auxiliary heat is running when outdoor temperatures aren’t extreme, a few things could be happening:

• Dirty air filter: Restricted airflow from a dirty air filter makes the system work harder.
• Thermostat issues: Incorrect thermostat settings or faulty sensors can trigger backup heat.
• Refrigerant problems: Low refrigerant levels reduce heat pump efficiency.
• Undersized system: The unit may struggle to keep up with your home’s heating demands.

If your energy bills suddenly spike and the aux heat light stays on constantly, that’s usually when it’s time to look deeper.

Auxiliary Heat vs Emergency Heat: What’s the Difference?

Homeowners often confuse auxiliary heat vs. emergency heat. They’re related, but they’re not the same thing.

Here’s a simple breakdown:

Auxiliary heat: Automatic backup that works with the heat pump.

Emergency heat: Manual setting used when the heat pump isn’t working properly.

Emergency heat is typically used if the outdoor unit is damaged or frozen solid. Running it long term can significantly increase energy costs.

Does Auxiliary Heat Mean Something Is Wrong?

Not necessarily. Auxiliary heat is built into the system for a reason. Seeing it occasionally during very cold weather is completely normal.

However, it can signal a problem if:

It runs constantly: Even in moderate temperatures.

Your home never reaches the set temperature: Despite extended run times.

Your electric bill jumps dramatically: Without a clear weather-related reason.

At that point, heating troubleshooting is worth considering. It could be something minor like airflow restriction. Or it could involve deeper mechanical issues.

How to Reduce Auxiliary Heat Usage

If you want to minimize how often your auxiliary heat runs, a few simple habits help:

Avoid large thermostat jumps: Increase temperature gradually.

Change air filters regularly: Clean airflow improves efficiency.

Schedule seasonal maintenance: A tuned system performs better in cold weather.

Seal air leaks: Drafts force your system to work harder.

For homeowners who suspect system performance issues, a diagnostic visit can help determine if you need heat pump repair.

When to Bring in a Pro

If your auxiliary heat stays on for long periods or your heating bills don’t make sense, it may help to have a professional take a look.

Glenmont Heating, Air Conditioning & Refrigeration can walk you through what your system is doing and whether it’s operating the way it should. If you’re in the area and want a second opinion, you can reach us at (227) 250-5844 or schedule an appointment online. 

FAQs About Auxiliary Heat

Is it expensive when auxiliary heat runs?

It can be. Electric resistance heat uses more energy than a heat pump alone. Short cycles during very cold weather are normal. Constant operation can increase utility costs.

Should I turn off auxiliary heat?

No. Auxiliary heat turns on automatically when needed. Manually switching to emergency heat without a reason can actually cost more.

How long should auxiliary heat stay on?

It depends on outdoor temperatures and your thermostat setting. During extreme cold, it may run longer. In mild conditions, it should cycle off once the set temperature is reached.

Why does auxiliary heat feel hotter?

Electric heat strips produce warmer supply air than a heat pump alone. That stronger blast of heat is often why homeowners notice it right away.

Your furnace shouldn’t be completely silent, but it also shouldn’t sound like a construction site. If you’re hearing new or unusual noises from your heating system, your furnace may be trying to tell you something important.

For homeowners in Rockville and throughout Montgomery County, strange furnace noises are one of the earliest warning signs of developing problems. Understanding what those sounds mean can help you take action early, avoid expensive breakdowns, and keep your home warm and safe all winter.

At Glenmont Heating & Air, we believe informed homeowners make smarter decisions. Here’s a homeowner-friendly guide to the most common furnace noises and what they usually indicate.

Normal Furnace Sounds vs. Warning Sounds

Before diving in, it’s helpful to know what’s normal. A furnace will naturally make soft clicking when it turns on, a low hum while running, and a gentle whoosh as warm air moves through the ducts.

Anything loud, sudden, repetitive, or new deserves attention.

Banging or Popping Noises

What It Often Means

Banging or popping sounds usually come from:

• Expanding and contracting ductwork 
• Dirty burners causing delayed ignition 
• Loose metal panels 

When metal heats up quickly, it can expand and make popping noises. While occasional popping isn’t always dangerous, frequent or loud bangs can signal burner or ignition issues that should be checked.

Why It Matters

Delayed ignition can strain your furnace and reduce efficiency. Left unchecked, it may lead to more serious component damage.

Rattling or Vibrating Sounds

What It Often Means

Rattling noises are commonly caused by:

• Loose screws or panels 
• Unsecured duct connections 
• Worn blower components 

These sounds may start small but tend to get worse over time.

Why It Matters

Loose parts can vibrate into bigger problems, potentially damaging internal components or causing airflow issues.

Screeching or Squealing Noises

What It Often Means

High-pitched screeching or squealing often points to:

• Worn blower motor bearings 
• A loose or failing belt (on older systems) 
• Motor issues 

This sound typically means friction where there shouldn’t be any.

Why It Matters

Blower motor problems can quickly escalate and may lead to system shutdown if ignored.

Booming or Loud Thuds at Startup

What It Often Means

A booming sound when the furnace starts can be caused by:

• Gas buildup before ignition 
• Dirty burners 
• Improper airflow 

This is not a normal sound and should be addressed promptly.

Why It Matters

Booming can stress the heat exchanger and create safety concerns if left unresolved.

Whistling or High-Pitched Air Sounds

What It Often Means

Whistling usually comes from:

• Dirty air filters 
• Blocked vents 
• Ductwork restrictions 

Restricted airflow forces air through small openings, creating a whistling sound.

Why It Matters

Poor airflow reduces comfort, increases energy bills, and puts extra strain on your furnace.

Clicking That Won’t Stop

What It Often Means

Continuous clicking may indicate:

• Failing relays or control boards 
• Ignition system problems 
• Electrical issues 

While a single click at startup is normal, repeated clicking is not.

Why It Matters

Electrical problems can prevent your furnace from starting reliably and may lead to complete system failure.

When to Call a Professional

If your furnace noise is:

• New or getting louder 
• Paired with uneven heating 
• Accompanied by rising energy bills 
• Happening frequently or unpredictably 

…it’s time to call a professional HVAC technician.

Ignoring warning sounds often turns a minor repair into a major expense.

How Maintenance Helps Prevent Furnace Noises

Routine furnace maintenance can:

• Tighten loose components 
• Clean burners and ignition systems 
• Lubricate moving parts 
• Identify worn components early 

Annual tune-ups are one of the best ways to keep your furnace running quietly and efficiently.

Trust Glenmont Heating & Air for Furnace Diagnostics

At Glenmont Heating & Air, we know that unusual furnace noises can be unsettling. Our experienced technicians take the time to diagnose the cause, explain what’s happening in plain language, and recommend the right solution, never unnecessary repairs.

If your furnace is banging, rattling, or making noises you don’t recognize, don’t wait for a breakdown.

Contact Glenmont Heating & Air today to schedule a professional furnace inspection and enjoy peace of mind all winter long.

If you live in Rockville, MD, you rely on your heat pump to keep your home warm and comfortable during chilly winter months. Unlike traditional furnaces, heat pumps move heat instead of generating it, which makes them efficient, but sometimes confusing for homeowners when temperatures drop.

If your heat pump isn’t keeping your home warm, you’re not alone. Many Rockville homeowners notice reduced heating performance in cold weather, but this doesn’t always mean your system is broken. Understanding how heat pumps work and what can affect their performance will help you troubleshoot issues and know when to call a professional.

How Heat Pumps Work in Cold Weather

Heat pumps transfer heat from outside air into your home, even when temperatures are cold. They’re highly efficient in moderate temperatures but can struggle as it gets closer to freezing. Modern systems often include a backup or supplemental electric heat to maintain warmth during very low temperatures.

Knowing this can help you distinguish between normal operation and a potential problem. For instance, it’s normal for a heat pump to run longer in cold weather because extracting heat from cold air takes more energy.

Common Reasons Your Heat Pump May Not Be Heating Properly

1. Dirty or Clogged Air Filters

Air filters trap dust, pet dander, and debris. When clogged, airflow is restricted, and your heat pump can’t efficiently transfer heat into your home.

Solution: Check and replace filters every 1–3 months, especially in winter.

2. Low Refrigerant Levels

Refrigerant is critical for heat transfer. If your system has a leak or low refrigerant charge, it won’t heat effectively. Low refrigerant can also damage the compressor if left unaddressed.

Solution: A certified HVAC technician can check levels, identify leaks, and recharge the system safely.

3. Frost or Ice Build-Up

Outdoor units can develop frost in cold, humid conditions. Most heat pumps have a defrost cycle, but if ice builds up excessively, it reduces efficiency and heating output.

Solution: Ensure the outdoor unit is clear of snow, leaves, and debris. If icing persists, a professional inspection is necessary.

4. Thermostat Settings

Sometimes the issue isn’t the heat pump but the thermostat. Settings like “emergency heat” mode or an incorrect temperature schedule can cause insufficient heating.

Solution: Verify thermostat settings and make sure it’s calibrated correctly. Smart thermostats may need firmware updates or battery changes.

5. System Age and Wear

Older heat pumps naturally lose efficiency over time. If your system is 10–15 years old, it may struggle to maintain temperature during extended cold spells, especially in Rockville winters that occasionally dip below freezing.

Solution: Regular maintenance can extend lifespan, but if your unit is aging and consistently underperforming, replacement may be the most cost-effective solution.

6. Defective Components

Components like the reversing valve, compressor, or sensors can fail, leading to reduced heating performance.

Solution: Only a licensed HVAC technician should inspect and repair these parts.

When to Call Glenmont Heating & Air

If you’ve tried basic troubleshooting, replacing filters, clearing the outdoor unit, and checking thermostat settings, but your home is still cold, it’s time to call a professional. Glenmont Heating & Air provides expert heat pump service for Rockville homeowners, including:

• Diagnostic checks for refrigerant leaks and low charge

• Compressor and reversing valve inspection

• Defrost cycle and sensor calibration

• Preventative maintenance to maximize efficiency

Professional service ensures your system operates safely, efficiently, and reliably during the coldest months.

Tips to Keep Your Heat Pump Performing in Winter

• Schedule annual maintenance before the winter season

• Keep outdoor units clear of debris, leaves, and snow

• Replace air filters regularly

• Monitor your thermostat settings and update batteries if needed

• Address unusual noises or reduced heating promptly

Following these steps helps prevent emergency breakdowns and keeps your Rockville home warm all season.

Don’t Wait Until It’s Too Cold

A heat pump that isn’t heating properly can leave your family uncomfortable and increase energy bills. If you notice any decline in performance, don’t wait—call Glenmont Heating & Air for professional inspection and repair.

Our team of certified technicians is ready to ensure your heat pump provides reliable warmth throughout the Rockville winter season.

Technology is rapidly changing when it comes to heating and cooling appliances, but how does that affect the way you stay warm? To answer that, let’s compare heat pumps vs. furnaces: which is best for your home? 

Glenmont Air Conditioning & Heating’s 40-year history of excellence reveals how passionate we feel about helping homeowners make the best cooling and heating decisions. Below, discover the difference between a heat pump and a furnace so that you can confidently consider your next upgrade.

Heat Pump vs. Furnace: How They Differ

First, let’s look at the functional side of heating a home. 

A furnace heats air using electrical power and heating coils or a gas-fueled flame. The way a furnace works is quite straightforward. The process also chews through a lot of energy.

Heat pumps don’t directly perform this function, but rather, they transfer hot air from outside, even in supposedly cold weather. The pumps operate using a refrigerant, much like an air conditioner. By changing the pressure of the refrigerant during its heating cycle, the heat pump can extract hot air from outdoor temperatures as low as 40 degrees.

Unlike a furnace, heat pumps can also reverse the process to cool down your home rather than heat it.

When You Should Install a Heat Pump

Can a heat pump provide sufficient heating for you? It can – in any of the following situations:

You Live in a Temperate Climate

So, heat pumps vs. furnaces: Which is best for your home? Location is the biggest determiner about which home heating systems you can use.

The heat pump experiences considerable performance issues when the temperature drops below 40 degrees. If you live in an area with milder winters, you’ll love having a heat pump.

You Have Safety Concerns

One of the best heat pump benefits includes its safety advantages, especially over a gas furnace. 

A gas furnace leak leaves your home vulnerable to health concerns or even an explosion. Because heat pumps use electricity, they’re much less volatile.

You Need Higher Energy Efficiency

While furnace efficiency has the advantage when it comes to time spent heating your home, heat pumps don’t use that much fuel for the heat they provide. 

Pumps use less energy than they transfer. A furnace loses energy in the process. You won’t pay as much to operate a heat pump.

When You Should Prioritize a Furnace

You should opt for a furnace if any of the following situations apply:

• You need heating performance that values speed over efficiency.
• You must prioritize short-term savings.
• You live in an area with freezing winters.

Schedule Services for Your Heating System Today

Given the details above, there’s only one thing to decide about heat pumps vs. furnaces: which is best for your home? 

If you still have questions about an HVAC issue or installation choice, Glenmont Air Conditioning & Heating’s family-owned business has the answers. Fill out our online form or call (301) 468-2665 today!

As the heart of winter beats on in Rockville, MD, with its stark landscapes and chill winds, your home remains a warm embrace even during the frost. During these months, when icicles form like crystal chandeliers from rooftops, the importance of a reliable and efficient heating system is even more vital than ever. 

It’s time to consider how your home stays warm and, more importantly, how it does so efficiently. Glenmont Heating & Air Conditioning is at the forefront, ensuring your home’s warmth doesn’t come with a chill when you see your energy bills. 

Unwrapping the Benefits: A Deep Dive Into Optimized Heating Systems 

In the heart of every home, the heating system hums a tune of comfort and warmth. But is it singing in harmony with your budget and eco-conscious mindset? With optimized heating systems, you can bring performance and efficiency together so they work with your wallet and environmental ideals. Here, in Rockville, Glenmont Heating & Air Conditioning is dedicated to fine-tuning that harmony to perfection. 

The Smart Heat: Navigating Optimized Heating Systems 

Stepping up your home’s heat doesn’t mean stepping down on savings. Embracing an optimized heating system means setting the stage for long-term financial and environmental wins. Here is how smart heating choices can lead to a more comfortable home and comfortable spending. 

• Energy Efficiency 
• Reduced Maintenance Costs 
• Improved Indoor Comfort 
• Smart Thermostat Integration 
• Environmental Sustainability 

Energy Efficiency: The Heat That Keeps on Giving 

Optimized heating systems are the silent champions of your home’s warmth, tirelessly working to deliver heat more effectively. Imagine a furnace that breathes air gently into every room, calibrated to use the minimal energy required to give you the maximum comfort. This is the marvel of modern engineering. 

High-efficiency units like furnaces and heat pumps can transform every ounce of energy into ambient, enveloping warmth. The result is a noticeably lighter load on your utility bills, month after month and year after year. Homeowners who choose this path see their investment pay off as steadily as the comforting heat that emanates from their vents. It’s a commitment to both your comfort and your budget. These systems give optimized heating systems that are a smart financial strategy. 

Reduced Maintenance Costs: The Unsung Hero of Home Heat 

Consider your heating system as a well-oiled machine. With regular check-ups, it will run with a purr rather than a clank. Addressing the small sounds before they become a ruckus means your system remains robust. It will be ready to serve you without the drama of breakdowns. This preventative approach not only wards off the inconvenience of sudden repairs but also ensures your system’s longevity. As each component works seamlessly, free from the strain of overcompensation, you’ll find that your system’s efficiency doesn’t dip as the years pass. It’s the kind of quiet assurance that comes from the regular, attentive care that keeps your home’s warmth humming along. 

Improved Indoor Comfort: A Consistently Cozy Abode 

The heart of a home beats warmest when comfort is a constant guest and optimized heating systems are critical to this endearing hospitality. They work silently behind the walls and beneath the floors to spread heat as evenly as a baker spreads icing on a cake. It will help to make sure that every room is just as inviting as the next. 

You won’t have to worry about the shivers as you step from the kitchen into the living room or piling blankets on the bed to fend off the chill of the night. Instead, a steady warmth pervades, a testament to the sophistication of a system that knows the rhythm of your life. It will adjust itself to your needs without fuss or fanfare. 

Smart Thermostat Integration: Your Command Center for Comfort and Savings 

Imagine living in a home that intuitively understands your schedule and adjusts its warmth to suit your life’s rhythms. That’s the convenience and intelligence of integrating smart thermostats with optimized heating systems. These clever devices are like having a personal heating assistant, always looking for ways to increase efficiency and comfort. 

• Remote Control: With a smart thermostat, you can easily adjust your home’s temperature from anywhere. 
• Customized Schedules: Smart thermostats learn your patterns and preferences, automatically dialing down the heat as you depart for work and ramping it back up just before you arrive home. 
• Insightful Reports: Smart thermostats offer insights into your heating habits, suggesting adjustments for even greater savings without compromising the toasty toes and warm wakes you cherish. 

This isn’t the future—it’s the present, and it’s all about giving you the control to tailor your environment while optimizing savings and efficiency. 

Environmental Sustainability: Heating That Heeds the Call of Nature 

Optimized heating systems whisper a promise of a greener tomorrow into the ears of today’s eco-conscious homeowners. By embracing efficiency, these systems take a stand against the tide of emissions that challenge our planet’s health, cutting down on energy use and the greenhouse gases that follow suit. 

When you choose to heat your home with methods that favor the earth, whether it is solar warmth or the embrace of geothermal energy, you’re casting a vote for the future. It’s a small but mighty act of stewardship, where every degree of warmth generated responsibly illuminates a path for others to follow. In this quiet revolution, your home can become a beacon of sustainability. Its warmth is a testament to the balance between human comfort and environmental respect. 

Take Charge of Your Comfort: Discover the Advantages of Optimized Heating Today 

As the days in Rockville shorten and the nights draw in, take a moment to think about how your heating choices affect the here and now and the years to come. Investing in an optimized heating system with Glenmont Heating & Air Conditioning means investing in a future where both your finances and the planet breathe easier. Ready to make a change? Let’s discuss how we can make your home a beacon of efficiency and comfort.