Preparing Your HVAC for an Austin Winter Storm: Lessons From 2021

Five Years Later, Austin Still Is Not Fully Prepared

February 2021 changed how every Austin homeowner thinks about winter. Pipes burst, power went out for days, and HVAC systems across the city were damaged or destroyed. Five years later, the grid is better but not bulletproof. And most homeowners still have not taken the basic steps to protect their HVAC systems from a repeat event.

I am not trying to scare you. I am trying to help you spend 2 hours and a few hundred dollars now instead of $5,000 to $15,000 after the next freeze.

What Actually Happened to HVAC Systems in 2021

When temperatures dropped to single digits and power went out for 3 to 5 days, several things happened to HVAC systems across Austin:

Frozen condensate lines. The PVC drain lines that carry water away from your AC unit froze and cracked. When the thaw came, water leaked into attics, walls, and ceilings.

Frozen outdoor coils. Heat pump systems that tried to run during the extreme cold had their outdoor coils freeze solid. Some compressors were damaged from trying to operate with frozen coils.

Cracked heat exchangers. When power returned and furnaces fired up after days of extreme cold, the rapid temperature change caused some heat exchangers to crack. A cracked heat exchanger can leak carbon monoxide, which is a serious safety hazard.

Burst water lines near HVAC equipment. Water lines running near outdoor HVAC equipment or through uninsulated areas froze and burst, causing water damage to the HVAC system and surrounding structure.

Pre-Winter Checklist for Your HVAC System

Do these things before the first freeze warning of the season:

Outdoor Unit Protection

Insulate exposed refrigerant lines. The copper lines running from your outdoor unit to the wall of your house should be wrapped in foam insulation. If the insulation is cracked, missing, or deteriorated, replace it. A roll of pipe insulation costs $5 to $15 at Home Depot or Lowe's.

Clear debris from around the unit. Make sure there is at least 2 feet of clearance around the outdoor unit. Remove leaves, mulch, and anything that could trap moisture against the unit.

Know where the emergency shutoff is. If you need to shut down your outdoor unit during a freeze, know where the disconnect switch is (the small box on the wall near the unit) and how to use it.

Indoor System Protection

Insulate condensate drain lines. If your condensate drain line runs through an unheated space (attic, exterior wall, crawl space), wrap it with pipe insulation. This is the single most overlooked item on every winter prep list, and it was one of the most common failure points in 2021.

Test your heating system before you need it. Turn on your heat in October or November and let it run for 30 minutes. Listen for unusual sounds, smell for burning odors (a brief burning smell on first use is normal as dust burns off, but it should clear within 15 minutes), and verify that warm air is coming from all vents.

Check your thermostat's emergency heat setting. If you have a heat pump, your thermostat has an "Emergency Heat" or "Aux Heat" setting. This bypasses the heat pump and uses the backup electric resistance heater or gas furnace. Know how to activate it. During extreme cold, you may need it.

Replace your filter. A clean filter ensures maximum airflow, which helps your heating system work as efficiently as possible when you need it most.

During a Winter Storm: What to Do

If you have power:

• Set your thermostat to 68°F and leave it there. Do not crank it up to 75. Your system will run continuously trying to reach that temperature and may overheat.
• Open cabinet doors under sinks to let warm air reach pipes near exterior walls.
• Keep interior doors open to allow heat to circulate throughout the house.
• If you have a heat pump and the outdoor unit is covered in ice, switch to Emergency Heat. Do not try to chip ice off the unit.

If you lose power:

• Turn your thermostat to OFF. This prevents the system from trying to restart repeatedly when power flickers on and off, which can damage the compressor.
• Close off rooms you are not using and gather in the smallest interior room. Body heat and a few candles can keep a small room surprisingly warm.
• If you have a gas fireplace, use it. If you have a wood-burning fireplace, use it. Do not use your gas oven or stove for heating. This is a carbon monoxide risk.
• Open faucets to a slow drip to prevent pipe freezing. Focus on faucets on exterior walls and in unheated spaces.
• If the indoor temperature drops below 40°F, shut off your water at the main valve and drain the lines. This is the nuclear option, but it prevents burst pipes.

When power comes back:

• Wait 5 minutes before turning your thermostat back on (the same rule as any power outage).
• Set it to 68°F and let the system warm up gradually.
• Listen for unusual sounds. If you hear banging, grinding, or the system short-cycling (turning on and off every few minutes), turn it off and call a technician.
• Check for water leaks around your indoor unit, especially if it is in the attic. Frozen condensate lines may have cracked and will leak as they thaw.

Upgrades Worth Considering

The first three items on this list cost under $350 total and prevent the most common winter storm HVAC failures. If you do nothing else, do those three.

The Bigger Picture

Austin's winters are mild 95% of the time. But that other 5% can be devastating if you are not prepared. The 2021 storm was not a once-in-a-lifetime event. Climate patterns suggest that polar vortex disruptions will continue to push extreme cold into Central Texas periodically.

The good news is that preparation is cheap and straightforward. A couple of hours of work in November can save you thousands in February.

If your system struggled during the last cold snap and you are wondering whether it is time for an upgrade, our pricing calculator [blocked] can show you what a new, more resilient system would cost.