Deer Park and La Porte Battery Backup: Power for Shelter-in-Place Country

Lin ZeriLin Zeri·
Single-story brick home on a quiet Deer Park street with the windows closed and a wall-mounted battery backup unit on the side wall, industrial towers faint on the horizon.

In Deer Park and La Porte, the outdoor warning sirens are tested every Saturday at noon, and the shelter-in-place drill is something the cities teach new residents on purpose. The protocol is short. Go inside. Close everything up. Stay informed until the all clear. It works, and people here follow it without drama.

What almost nobody notices is how much of it runs on electricity. Read the official instructions line by line and only the first step, sealing the house, survives a dead grid. Cooling, alerts, the radio, the phone, the all-clear message: every one of those needs a live circuit. This guide walks the protocol against a real backup load list, then sizes a battery for an east Harris County home.

Key Takeaways

  • Both cities instruct residents to close all doors and windows and turn off air conditioning or heating during a shelter-in-place order (City of Deer Park; City of La Porte).
  • The all clear arrives by automated phone call, social media, and the city cable channel, so the alert path itself depends on power (City of Deer Park).
  • The 2019 Deer Park tank fire burned for three days and was found preventable by federal investigators (U.S. Chemical Safety Board, 2023).
  • A shelter-in-place load list is comms and fans first, air conditioning second, which is a different sizing problem than a hurricane load list.
Check what a backup system would cover at your address→

What a shelter-in-place order actually asks your house to do

Deer Park publishes the instruction plainly: "Close all doors, windows and other sources of outside air," then "Turn off air conditioning or heating systems and close the fireplace damper to keep chemical vapors from entering" (City of Deer Park). Residents are told to cover gaps with wet towels or sheets. La Porte's version is nearly identical: go inside, close all doors and windows, turn off the A/C or heating (City of La Porte).

That last step is the one that matters for backup planning. The order does not tell you to put the system on recirculate. It tells you to shut it off, because a running air handler pulls outside air toward a house you were just told to seal.

So how do you stay cool in a sealed Gulf Coast house in August? Deer Park answers that too: "Ceiling fans or rotary fans inside the building can be safely used to keep cool." Fans are electric.

The information path is electric as well. La Porte's siren brochure tells residents to tune the radio to AM 830 and stay off the phone so officials can reach them, and it notes that the 13 outdoor sirens are tested every Saturday at noon and that any other activation should be treated as a real emergency (City of La Porte). Deer Park's all clear comes over an automated telephone notification system, Facebook, X, and the city cable channel.

Citation capsule: Deer Park's shelter-in-place protocol instructs residents to close all outside air sources and turn off air conditioning or heating, permits ceiling or rotary fans indoors for cooling, and delivers the all clear by automated telephone notification, social media, and the city cable channel (City of Deer Park).

Every part of that after "close up" needs power. Our Houston service area page covers the wider metro, but this corridor has its own version of the problem.

The scenario the guides skip: a shelter-in-place order while the power is out

Two hazards sit on the same map here, and each one has already happened. The 2019 Deer Park tank fire burned for three days. Federal investigators later concluded it was preventable, finding that the tank where it started had no flammable gas detection system and no remotely operated emergency isolation valves (U.S. Chemical Safety Board, 2023).

Air quality drove the public response. Because of benzene concerns, a shelter-in-place was issued for the entire City of Deer Park at one point, schools and businesses closed or ran altered schedules, and a seven-mile stretch of the Houston Ship Channel was shut (U.S. Chemical Safety Board, 2023). An order lifting is not the same moment as everything returning to normal.

The other hazard is the grid. In July 2024, Hurricane Beryl knocked out power to roughly 2.2 million CenterPoint customers at peak, more than a million were still dark days later (Houston Public Media, 2024), and National Weather Service heat indices ran 100 to 106 F while crews worked (NWS Houston/Galveston, 2024).

Neither event caused the other. The 2019 fire did not happen during a blackout, and Beryl was not a chemical release. But they are two documented hazards in the same few ZIP codes, and hurricane season is also the season with the highest odds of a multi-day outage.

Picture the overlap in four beats. The siren sounds. You seal the house. The grid is already down, so there is no air conditioning and no fan. Your phone is at 30 percent, the TV is dark, and the cable channel carrying the all clear is unreachable.

Citation capsule: East Harris County carries two documented hazards at once: a 2019 tank fire that burned three days and triggered a citywide shelter-in-place over benzene concerns (U.S. Chemical Safety Board, 2023), and a July 2024 storm that left roughly 2.2 million CenterPoint customers without power (Houston Public Media, 2024).

What actually needs to stay on when you cannot step outside

A shelter-in-place load list is not a hurricane load list. During a hurricane you want the whole house comfortable for days. During a shelter-in-place order you want five specific things, in this order:

  1. Router, modem, and phone charging. The automated call and the social posts land here first.
  2. Ceiling and rotary fans. The only cooling the protocol permits while the order stands.
  3. One TV or one radio. The city cable channel and AM 830 are both named alert channels.
  4. The refrigerator, plus any refrigerated medication.
  5. Central air conditioning, the moment the all clear lands, to pull a sealed house back down.

Notice the asymmetry. Items one through four are small continuous loads that add up to a few hundred watts. Item five is a surge event. One Eos controller supplies 11.5 kW continuous with 17.1 kW surge, which is exactly what lets a system idle quietly for hours on fans and comms, then restart a compressor without stalling.

Relative draw of shelter-in-place loads Horizontal bar chart comparing relative continuous power draw of shelter-in-place loads. Router and modem plus phone charging is very low, ceiling and rotary fans are low, one television or radio is low, the refrigerator is moderate and cycling, and central air conditioning is by far the largest, driven by compressor startup surge. Relative draw of shelter-in-place loads Router, modem, phone very low Ceiling and rotary fans low One TV or radio low Refrigerator moderate, cycling Central air conditioning high, plus startup surge Relative bands, not measured wattage. Bars show order of magnitude only. Source: Eos site survey load audits, east Harris County, 2026

On site surveys in 77536 and 77571, the protected-circuit list homeowners ask for looks different from the generic essentials list. Almost everyone names the router and modem first. Ceiling fans in two or three rooms come next. Then a single television, the refrigerator, and one bathroom outlet. Very few ask for the whole house. What surprises people is how often they forget the garage door opener until we bring it up.

Our guide to

Keeping a Houston house cool when the power is out→
goes deeper on the fan versus air conditioning math.

Why the generator answer fits this corridor badly

Here is the awkward part. The standard Gulf Coast backup recommendation asks you to do several things a shelter-in-place order explicitly tells you not to do.

A portable generator has to be carried out, started outdoors, and refueled outdoors, usually every several hours. Every one of those is a trip outside during an order whose entire purpose is keeping you inside a sealed building. That is not a small inconvenience in this corridor. It is the opposite of the instruction.

A standby unit clears that bar, since it runs unattended and starts on its own. But it is still a combustion device drawing air and venting exhaust at the perimeter of a house you were just told to seal against outside air. It also runs loud, and that noise sits between you and the outdoor siren that is the primary alert channel in La Porte, Morgan's Point, and Shoreacres.

To be fair to generators: on natural gas, a standby unit runs as long as the gas keeps flowing, and a battery does not. For a week-long winter event, that matters. Our post on

Generator noise, fuel and fumes in Houston neighborhoods→
covers the tradeoff in full.

A battery is silent, vents nothing, needs no outdoor trip, and takes over automatically. For the specific scenario this corridor drills for, that combination is hard to beat.

Sizing a battery for a Deer Park or La Porte home

Each Eos battery module holds 9 kWh nominal and 8.76 kWh usable, so the sizing question becomes simple to state: how many hours of fans, comms, and refrigeration do you want, and how many air conditioning restarts on top of that?

Both cities sit in the mid-30,000 range for population and are overwhelmingly single-family, with a lot of housing stock built before current envelope standards (U.S. Census Bureau QuickFacts, Deer Park; U.S. Census Bureau QuickFacts, La Porte). A leakier envelope heats up faster once the air conditioning is off, which pushes fan runtime up, not down.

Map the tiers by behavior rather than by budget. A single 9 kWh module suits a true essentials-only setup: comms, a few fans, the fridge, lights. Two modules at 18 kWh is the realistic floor once you want central air conditioning back the moment the all clear lands. Three modules and up fit larger or all-electric homes where the compressor will cycle repeatedly.

The surge number decides the tier more often than the kWh number does. A residential compressor start is the load that stalls undersized equipment, and 17.1 kW of surge headroom is what lets it happen on battery at all.

See which system size fits your home→

The bay side adds a second problem: surge and evacuation

La Porte, Morgan's Point, and Shoreacres sit on the west shore of Galveston Bay, inside the bay-side ZIP evacuation zones that Harris County calls first (NOAA National Weather Service Houston/Galveston). Deer Park sits further inland, so its profile is wind and outage first, surge second.

The reference event is still Ike. It came ashore on September 13, 2008, and water reached between 10 and 15 feet on Galveston Island and the west side of Galveston Bay, with a 17.5 foot high water mark recorded about ten miles inland in Chambers County (NOAA National Weather Service Houston/Galveston).

For an install, that changes placement, not feasibility. On the bay side we look hard at mounting height, at where the equipment sits relative to the slab and to known water lines, and at how the enclosure is protected. The site survey settles all of it before anything is ordered.

One thing needs saying flatly, because some backup marketing implies otherwise. A battery is a reason to stay comfortable through an outage. It is never a reason to stay through a mandatory evacuation. If the county calls your zone, you leave, and the system waits for you.

Citation capsule: Bay-side communities including La Porte carry storm surge exposure that inland Deer Park does not. During Hurricane Ike in September 2008, water reached 10 to 15 feet on Galveston Island and the west side of Galveston Bay, with a 17.5 foot high water mark about ten miles inland (NOAA National Weather Service Houston/Galveston).

For the nearest stretch of the same corridor, see our Pasadena service page, and our companion piece on

How the Ship Channel grid behaves in Pasadena→
.

Start your Houston backup plan→

Or call Eos at 833-989-3737 to talk through your setup with an installer.

Frequently Asked Questions

Do I turn the AC off during a shelter-in-place order in Deer Park?

Yes. The city instructs residents to turn off air conditioning or heating systems and close the fireplace damper so chemical vapors cannot be pulled inside. Ceiling fans or rotary fans indoors are explicitly permitted to keep cool while the order stands (City of Deer Park).

Does a home battery help during a shelter-in-place order?

It helps with every part of the protocol that needs electricity: fans for cooling, the router and phone charging, a TV or radio for the all clear, the refrigerator, and restoring central air conditioning once the order lifts. It does not seal the house for you.

What size battery does a typical Deer Park home need?

It depends on behavior, not square footage alone. Essentials only points to a single 9 kWh module. Wanting central air conditioning back immediately after the all clear points to two modules or more. Compare the configurations on our plans page and confirm the answer with a site survey.

Is a generator a problem during a shelter-in-place order?

Portable units require going outside to start and refuel, which contradicts the order. Standby units run unattended but burn fuel and vent exhaust at the perimeter of a sealed house, and their running noise competes with the outdoor warning sirens that La Porte, Morgan's Point, and Shoreacres rely on (City of La Porte).

The short version

  • The shelter-in-place protocol is power dependent from step two onward. Sealing the house is the only part that works with the grid down.
  • This corridor stacks two documented hazards, a chemical release and a multi-day outage, inside the same few ZIP codes.
  • A battery covers the indoor scenario silently, which is the scenario a generator handles worst.

If you want the wider metro picture first, start with our

Houston power outage preparedness guide→
.

Sources

Lin Zeri is the lead site surveyor at Eos Backup and Battery and runs installs across east Harris County, including Deer Park, La Porte, Pasadena, and the bay-side communities on the west shore of Galveston Bay.

Deer ParkLa Portebattery backupshelter in placeeast Harris CountyHouston Ship Channelhome battery