Local Furnace Repair Specialists
Get your furnace back up and running quickly with our certified HVAC technicians. Serving Alexandria and surrounding areas, we come fully equipped to handle most repairs on the spot, so you can enjoy a warm, comfortable home without waiting for a second visit.
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Professional Repairs for All Furnace Problems in Northern Virginia
When your furnace fails, you need fast, expert service that gets the job done right. HVAC & Plumbing Unlimited provides professional furnace repair throughout Alexandria, Fairfax, and the surrounding areas. Our certified technicians are factory trained and equipped with advanced diagnostics and fully stocked vehicles to complete most furnace repairs in a single visit. We work on all major furnace brands and systems, offering reliable service, clear communication, and minimal downtime. Contract customers also benefit from after-hours emergency support for critical heating issues. Since 2006, we’ve delivered top-tier heating services backed by a 100% satisfaction guarantee.
Call (703) 337-4892 or contact us online to schedule furnace repair anywhere in Northern Virginia.
Common Furnace Problems
Furnace problems are never fun, especially during the coldest parts of the winter. At HVAC & Plumbing Unlimited, some of the most common furnace problems we encounter include:
- Faulty thermostats – If your thermostat is damaged, has no power, or is set incorrectly, it may prevent your furnace from running correctly.
- Frequent cycling – If your furnace turns on and off more often than usual, the fan limit switch may be faulty, the air filter may be clogged, or the thermostat may be in a drafty location.
- The burners will not stay lit – If the burners will not light or stay lit, the burners may be dirty, the thermocouple may be faulty, or the pilot light may have gone out on older models. On newer furnaces, the igniter may be faulty or the flame sensor may be dirty.
- Rollout – If you see flames escape the furnace or hear a large thump on startup, the igniter may be faulty, the pilot light may be poorly adjusted, or the burners may be dirty, causing delayed ignition.
- Poor heat output – If your furnace cannot keep up with the cold, it may be due to dirty burners, a clogged filter, or a faulty fan limiter.
Need to fix your furnace fast? call (703) 337-4892 or contact us online.
Repair or Replace? Knowing When to Upgrade Your Furnace
Not every furnace issue calls for a full system replacement. In many cases, a professional repair can restore reliable performance and extend your system’s lifespan. But when problems become frequent or the system is nearing the end of its expected life, replacement may be the smarter, more cost-effective choice.
Repairs make sense when:
- Your furnace is less than 10–12 years old
- Issues are limited to one or two components
- Repair costs are minor compared to replacement
- Energy bills haven’t significantly increased
- The system still heats your home evenly and effectively
Replacement is recommended when:
- Your furnace is 15+ years old
- Repairs are becoming more frequent or costly
- You notice rising heating bills and declining performance
- The heat exchanger is cracked or major components fail
- You want to upgrade to a more efficient, modern system
Our experts at HVAC & Plumbing Unlimited will always provide honest recommendations based on system condition, cost-benefit analysis, and long-term reliability. We offer both repair and replacement services—and help you make the best choice for your home and budget.
Can I Repair My Furnace Myself?
While DIY furnace repairs can seem like an excellent way to save money, they could put the health and safety of your family in jeopardy. Furnaces are fuel-burning appliances, and as such, if they are not working properly, combustion gases could escape into the home. These gases include carbon monoxide, a tasteless, odorless, invisible gas that can cause serious illness or even death with extended exposure. Likewise, fuel leaks can pose a risk of fire, as can faulty electrical wiring. It is always best to call a professional for safe, reliable furnace repairs, plus DIY repairs will likely void your furnace’s warranty.
Schedule a Furnace Service with Trusted Local Experts
Don’t wait for a complete breakdown. We deliver fast, professional furnace repair throughout Alexandria and Northern Virginia.
Why choose us?
- Rapid response and fully stocked service vehicles
- Certified technicians trained on all major systems
- Transparent pricing with no upsells
- Emergency service available for contract customers
- Backed by a 100% satisfaction guarantee
Call (703) 337-4892 or contact us online to book your furnace repair today.
Other Furnace Services
24/7 EMERGENCY SERVICE
If you’re having a home emergency, you don’t want to wait a minute too long. That’s why our technicians and plumbers are available to solve problems 24 hours a day, and that includes weekends and holidays. After all, things always break at inconvenient times.
FURNACE MAINTENANCE & TUNE-UPS
Keep your heating system running at peak performance with professional furnace maintenance from HVAC & Plumbing Unlimited. Our certified technicians provide full-system inspections, cleanings, and precision tune-ups to reduce breakdowns, lower energy costs, and extend your furnace’s lifespan.
FURNACE INSTALLATION
Upgrade your heating system with expert furnace installation from HVAC & Plumbing Unlimited. We install high-efficiency gas, electric, and oil furnaces tailored to your home’s needs—backed by certified technicians, trusted Carrier products, and a 100% satisfaction guarantee.
AFFORDABLE WELLS FARGO FINANCING
Money should never get in the way of your family’s safety and comfort. We’ve arranged special payment options through Wells Fargo Financing that let you start enjoying your new system or repairs right away and pay for it over several months.
FAQ About Furnaces
How Do You Properly Size a Furnace?
It is crucial to find a furnace that perfectly fits your home. When it comes to choosing the size, it is not about measuring the physical size of the furnace; it is about determining how many British thermal units, or BTU, the unit produces. In other words, how much heat the system can generate to keep you comfortable on a cold winter’s day.
To calculate the best-sized system for your home, you need to take into account the following:
- Your home’s square footage
- Your climate zone (Northern Virginia is Zone 3)
- The number of windows in your home
- The thickness and type of insulation in your home
Generally, Northern Virginia homeowners will want a furnace that can produce between 40 to 45 BTUs per square foot. This size is usually more than sufficient to stave off the chill on the coldest days of the year.
Do you need help choosing the ideal size furnace for your home? Contact us at (703) 337-4892, and we will be happy to help you make the calculations you need to enjoy the comfort you desire.
Can I install a furnace myself?
Whether it’s gas, electric, or oil, there is no shortage of YouTube videos and blogs that attempt to walk homeowners through the process of installing a new furnace. And, while we fully support many DIY projects, we strongly recommend against trying to install your own furnace. There are many reasons, not the least of which is your safety. When you install a furnace, you will be dealing with electricity and fuel in the case of gas or oil furnaces. Mishandling these can result in electrocution, fires, or explosions.
When you install a new furnace, every task must be performed correctly, in the right order, and in compliance with fire codes, building codes, manufacturer requirements, and other standards. A single mistake is all it takes to void the warranty, homeowners insurance, etc. It is simpler, faster, safer, and more cost-effective to hire a trained HVAC professional to perform the installation process. The installation will take between four to eight hours from start to finish, and it is worth every penny of your investment.
I’ve replaced my furnace, so why is my house still cold?
If you have replaced your furnace but your home is still cold, there are several possible causes. First, you most likely have an air leak. Check your windows, doors, skylights, etc., to make sure they are properly sealed with the appropriate weatherstripping. If that’s not the issue, then it is probable that your insulation is compacted or has blown away from walls, attics, etc.
Why do heat exchangers crack?
Cracked heat exchangers are one of the most common repairs we provide. Heat exchangers can crack when they overheat because of the excess stress caused as the component expands and contracts. This process can cause cracks, usually next to bends or welds. They can also crack due to incomplete combustion, poor airflow, or if the unit is under/oversized for the home.