Furnace Repair in Northern Virginia: Warning Signs, Quick Fixes & Who to Call

Updated October 2026

The first cold night of the year is when furnaces fail. A system that sat idle all summer gets asked to run for hours, and anything that was borderline (a dirty flame sensor, a weak igniter, a clogged filter) shows up all at once.

This guide walks through what to check yourself before you call, the warning signs that mean you need a technician, and Northern Virginia HVAC companies that advertise emergency or same-day heating service. For the full list of 30 local heating contractors, see our best HVAC companies in Northern Virginia.

If you smell gas, leave the house first. Don’t flip switches or use your phone inside. Once you’re outside, call your gas company’s emergency line or 911.

Check these 6 things before you call

1. Thermostat. Make sure it’s set to Heat, the setpoint is above room temperature, and the batteries aren’t dead.
2. Breaker and switch. Look for a tripped breaker in the panel and a light-switch style power switch on or near the furnace that may have been turned off.
3. Air filter. A clogged filter can make a furnace overheat and shut itself off. Replace it if you can’t see light through it.
4. Furnace door. Most furnaces won’t run if the front panel isn’t seated properly, because a safety switch stays open.
5. Vents and returns. Make sure supply vents are open and nothing is blocking the return grilles.
6. Condensate line (high-efficiency furnaces). If the drain line or pump is clogged, the furnace may shut down. Look for water around the unit.

Signs you need a technician

• The furnace starts, then shuts off within a few minutes (short cycling).
• Burner flame is yellow or flickering instead of steady blue.
• Loud banging, screeching or rumbling when it starts.
• Your carbon monoxide detector goes off. Get everyone outside and call 911 first.
• Some rooms stay cold even though the system runs constantly.
• Heating bills jumped without a change in how you use the house.

Repair or replace?

Most furnaces last about 15 to 20 years. If yours is near that age, needs a major part such as a heat exchanger or blower motor, or has needed several repairs in the last couple of years, ask for a replacement quote alongside the repair estimate. A cracked heat exchanger is a safety problem, not just an efficiency one, so don’t keep running a furnace that has one.

If you’re replacing, it’s worth asking whether a heat pump (or a dual-fuel heat pump with a gas furnace backup) makes sense for your home. Many Northern Virginia homes already have one.

Northern Virginia HVAC companies with emergency or same-day heating service

These companies say on their own websites that they offer emergency, after-hours or same-day service. Confirm hours and after-hours fees when you call.

Frosty’s Heating & Cooling, Inc.

Alexandria, VA. Locally owned heating and cooling company established in 1989 and serving Alexandria, Fairfax County and the metro DC area. Installs and repairs furnaces, heat pumps and ductless mini-splits, with emergency service available 365 days a year. View listing and contact info

COTC Mechanical (Creators of Total Comfort)

Haymarket, VA. Creators of Total Comfort Mechanical is a Haymarket-based HVAC contractor serving Prince William County and the surrounding Northern Virginia area. After-hours emergency calls are taken by phone. View listing and contact info

T&T Associates, Inc.

Herndon, VA. Family-owned and operated HVAC company in Herndon, founded in 1984. Offers 24/7 emergency service. View listing and contact info

Reddick & Sons Inc.

Manassas, VA. Family-owned Manassas contractor offering HVAC, plumbing and electrical service for more than 20 years. Repairs and installs furnaces and heat pumps across Prince William, Fairfax and Loudoun counties, with service available 24 hours a day. View listing and contact info

EverCool Heating and Cooling, Inc.

Springfield, VA. Family-owned heating and cooling company in Springfield, founded in 2003. Carrier factory-authorized dealer with NATE-certified technicians and 24/7 emergency service. View listing and contact info

Donmar Heating, Cooling & Plumbing

Sterling, VA. Family-owned heating, cooling and plumbing company founded in 1990 and based in Sterling. Also handles air filtration, humidifiers and emergency service seven days a week. View listing and contact info

Briggs Heating & Air Conditioning

Woodbridge, VA. Family-owned and operated heating and air conditioning sales, repair and maintenance company in Woodbridge. Offers emergency service, maintenance plans and financing. View listing and contact info

Prevent the next breakdown

• Replace 1-inch filters every 1 to 3 months during heating season.
• Book a tune-up every fall. Most of the companies above offer yearly maintenance plans with priority scheduling.
• Keep the area around the furnace clear of storage, especially anything flammable.
• Test carbon monoxide detectors every month during heating season.

More heating help

See all 30 local heating contractors in our best HVAC companies in Northern Virginia guide, or browse our guides for Maryland and Washington DC. If cold weather freezes a pipe, see our list of plumbers in DC, Maryland and Northern Virginia.

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