Preparing Your Home for a Rio Grande Valley Freeze

Hard freezes in the Rio Grande Valley are rare. That rarity is precisely what makes them disruptive.

Homes here are built for heat, not cold. Heating equipment sits unused for most of the year. Pipe insulation is minimal. And when a freeze does arrive, every household in the region discovers all of this at the same moment, which is why HVAC and plumbing services are overwhelmed within hours.

Here is how to be ready.

The single most useful thing: test your heat in October#

Valley heating equipment does not wear out. It fails from sitting still.

Over eight or nine months of disuse, hot surface igniters crack, flame sensors develop oxidation, sequencers stick, capacitors weaken, and dust settles on heat exchangers and heat strips. None of it produces any symptom until the moment you switch to heat.

That moment is usually 10pm on the first genuinely cold night, which is also when every other household in the Valley is discovering the same thing about their own system.

The test takes 15 minutes:

1. Pick a cool morning in October or November
2. Switch the thermostat to HEAT and set it several degrees above room temperature
3. Let it run for 15 minutes
4. Put your hand in the airflow at a supply register

The air should be genuinely warm. On a gas furnace, expect 120 to 140 degrees at the supply. On a heat pump, expect 85 to 95, which is warmer than the room but cooler than your skin, so it will feel cool at the vent. That is normal for a heat pump.

A burning smell in the first few minutes is normal. Dust burning off the heat exchanger or heat strips. It should fade within about 20 minutes. If it persists, smells like burning plastic, or is accompanied by smoke, shut it off and call.

If the system does not produce warm air, or produces it intermittently, that is the whole point of testing in October. Call and get it repaired on a normal schedule.

Check your carbon monoxide detectors#

If you have any gas appliance, this is not optional and it is inexpensive.

Test the detectors, replace the batteries, and check the manufacture date. Carbon monoxide detectors have a finite sensor life, typically five to seven years, and an expired detector gives false reassurance.

The risk rises during a freeze specifically because gas appliances run harder, homes are sealed up tighter, and people occasionally resort to unsafe heating methods.

Know what not to do for heat#

Every freeze event produces preventable carbon monoxide incidents. These are the ones to avoid:

• Never use a gas oven or stovetop to heat a room. It is not designed for it and it produces carbon monoxide in an unventilated space.
• Never run a generator indoors, in a garage, or near a window. Outside, well away from the house, exhaust directed away from any opening.
• Never use an outdoor propane or charcoal heater indoors, including in a garage with the door partly open.
• Space heaters need clearance. Three feet from anything combustible, plugged directly into a wall outlet rather than an extension cord, and never left running unattended or while asleep.

Before a freeze warning#

When forecasters call for a hard freeze, do these:

Change the air filter. Your heating system is about to work harder than it has all year. A clogged filter restricts airflow, which on a gas furnace causes the high limit switch to trip and shut it down, and on electric heat causes the same nuisance shutdowns.

Open cabinet doors under sinks on exterior walls so warm air reaches the plumbing.

Let faucets drip, especially those served by pipes running through unconditioned space or along exterior walls. Valley homes generally have less pipe insulation than homes in colder regions, so this matters more here than the mild average climate suggests.

Disconnect and drain garden hoses, and cover outdoor spigots. A hose left connected traps water in the spigot, which freezes and splits the pipe inside the wall.

Cover or bring in vulnerable plants, since Valley landscaping is generally not freeze hardy.

Set the thermostat to a steady temperature rather than using setbacks. Recovering from a deep setback during a freeze is exactly what drives auxiliary electric heat to run at full output, and on a heat pump that is expensive.

Know where your water shutoff is, so that if a pipe does burst you can stop it in seconds rather than searching while water runs.

If you have a heat pump#

Two things worth understanding.

Capacity drops as it gets colder. A heat pump extracts heat from outdoor air, and there is less to extract at 32 degrees than at 50. That is why heat pumps are paired with backup electric heat strips. During a hard freeze the backup carries part of the load, which is by design.

Avoid deep setbacks. Recovering a large temperature swing triggers the auxiliary heat you are trying to avoid using. Two to four degrees is plenty in winter.

Check your auxiliary heat configuration. If your winter bills seem much higher than they should be, the most common cause is a thermostat configured so the heat strips engage whenever the heat pump runs. That is a settings problem, and correcting it is one of the cheapest wins available.

During an extended outage#

Freezes in this region have caused extended power outages, so it is worth thinking through in advance.

Retain heat. Close off unused rooms. Close blinds at night to reduce radiant loss, and open south facing ones during the day for solar gain. Gather everyone into one room.

Layer clothing and use blankets. Multiple thin layers retain heat better than one thick one.

Keep the refrigerator and freezer closed. A full freezer holds temperature for roughly 48 hours unopened.

Check on neighbors, particularly older adults and anyone living alone. A cold house is a genuine health risk for vulnerable people, and it develops quietly.

After the freeze#

Check for water damage. Burst pipes sometimes do not reveal themselves until things thaw. Look under sinks, in the attic, in the garage, and at exterior walls.

Look at the outdoor unit. Heat pumps ice up in cold damp conditions and normally clear themselves through defrost cycles. If ice remains on the outdoor coil after conditions warm, call, because it means the defrost system is not working.

Do not chip ice off the outdoor unit. The coil tubing is thin and punctures easily.

Have anything that struggled looked at. Equipment that barely kept up during the freeze is telling you something before the next one.

Fall checklist#

• Test the heat for 15 minutes in October or November
• Replace the air filter
• Test carbon monoxide detectors and check their expiration dates
• Have gas equipment inspected, including the heat exchanger
• Confirm heat pump auxiliary heat staging is configured correctly
• Locate your water shutoff
• Know which faucets to drip

The short version#

Test your heat in October. Valley heating equipment fails from sitting idle, not from wear, and finding that failure in the fall means a scheduled repair rather than waiting behind the entire region during a freeze warning. Then change the filter, check the carbon monoxide detectors, and know where the water shutoff is.