Guides · Quick answers
How long can a house go without power
A house does not fail all at once. The fridge goes first, then water and medicine, then temperature. This timeline shows which system runs out when, and what extends each one.
By PowerLockdown EditorialUpdated November 1, 20268 min readHow we research
In this guide
- 01The short answer
- 02The timeline, system by system
- 03How long can a refrigerator go without power
- 04Water, toilets and drains
- 05Pipes, heat and cold
- 06Heat without air conditioning
- 07Medicine and medical devices
- 08How to survive without electricity for days
- 09Gear that stretches the clock
- QFrequently asked questions
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The short answer
A house can go about 4 hours without power before refrigerated food is at risk, and about 48 hours before a full freezer is (CDC, FDA). Refrigerated medicine has about a day (Ready.gov). After that, the limits are water, heat and cold: with stored water, a safe heat source and a plan, a household can manage for weeks.
The building itself does not care how long the power is off. What fails is the equipment inside it, and each piece has its own clock. The question to ask is which of your systems runs out first, and what you can do to stretch it. How long outages themselves usually last is covered in how long power outages last.
The timeline, system by system
| System | Lasts about | What extends it |
|---|---|---|
| Refrigerator (door closed) | 4 hours | Cooler and ice; a power station that can run the fridge |
| Freezer (full, door closed) | 48 hours | Keep it full; do not open it |
| Freezer (half full, door closed) | 24 hours | Group packages together |
| Refrigerated medicine | About 1 day, unless the label says otherwise | Insulated cooler; ask the pharmacist about your drug |
| Insulin vials and cartridges | Up to 28 days at 59°F to 86°F | Keep out of heat and sunlight; do not freeze |
| Phones | Hours to a day or two, depending on use | Power banks, car charger, power station |
| Water from a private well | Only what is left in the pressure tank | Stored water; a generator or station sized for the pump |
| Water from a city system | Usually longer, but pressure can drop | Stored water; follow utility notices |
| Sump pump | Stops immediately | Battery or water-powered backup pump |
| Furnace or heat pump | Stops immediately (most need electricity) | A warm room and a safe, indoor-rated heat source |
| Central air conditioning | Stops immediately | Shade, ventilation at night, cooling centers |
| Water pipes in unheated spaces | At risk when it is 20°F or below outside | Open cabinet doors; shut off and drain lines if leaving |
How long can a refrigerator go without power
CDC says a refrigerator keeps food safe for up to 4 hours without power if you do not open the door. A full freezer holds for 48 hours, or 24 if half full. After 4 hours, refrigerated perishables such as meat, poultry, fish, eggs and leftovers should be thrown out or should already be in a cooler with ice. Thermometers settle the question; the details are in keep food safe during a power outage.
This is the cheapest system to extend. A cooler and bags of ice buy a day. A portable power station sized to your fridge's draw can keep it cold through a short outage; the sizing math is in best power station for a refrigerator, and BackupPowerAI covers how to power a refrigerator during an outage.
Water, toilets and drains
Homes on a private well lose running water as soon as the pressure tank drains, because the pump needs electricity. Homes on city water usually keep pressure longer, but EPA's power outage checklist for utilities lists pressure losses, boil water advisories, reduced treatment and sewage backups among the possible effects of losing grid power at water and wastewater plants.
- Store water before you need it: Ready.gov's guideline is 1 gallon per person per day. See water when the taps stop.
- Toilets on gravity flush systems can still be flushed with a bucket of water if the sewer works. Details: how to flush a toilet without power.
- If you have a basement ejector or grinder pump, limit drain use until power returns, or waste can back up into the lowest fixture.
Pipes, heat and cold
Texas A&M AgriLife Extension says water pipes can freeze and burst when the outside temperature reaches 20°F or below, starting with pipes in attics, crawl spaces, garages and exterior walls. Without heat, a house cools toward the outdoor temperature; how fast depends on insulation and wind, so watch an indoor thermometer rather than a clock.
- Open kitchen and bathroom cabinet doors so warmer room air reaches the plumbing (Texas A&M AgriLife).
- If you leave the house in cold weather with heat available, the same guide says to set the thermostat no lower than 55°F.
- If a long, freezing outage is certain and you are leaving, shut off the main valve and drain the lines.
People are more fragile than pipes. In the February 2021 Texas storm, the state counted 246 storm-related deaths, 161 of them from extreme cold and 19 from carbon monoxide (Texas DSHS). CDC says a body temperature below 95°F is a medical emergency. The answer is one warm room and an indoor-safe heat source, covered in heating without power and winter power outage survival.
Heat without air conditioning
Air conditioning stops with the power, and Ready.gov defines extreme heat as temperatures above 90°F for at least two to three days. A closed house in a heat wave can stay hot overnight. Heat is the faster danger for older adults, infants and people with chronic conditions. Read how to stay cool without power, and know where your nearest cooling center is before the outage.
Medicine and medical devices
Ready.gov: if the power is out for more than a day, discard medication that should be refrigerated, unless the label says otherwise. FDA says insulin vials or cartridges can stay unrefrigerated between 59°F and 86°F for up to 28 days. Powered medical devices last only as long as their batteries. For anyone on oxygen or CPAP, that battery runtime is the true limit on how long the house can go without power. See best CPAP battery backup.
How to survive without electricity for days
Most households can handle a day without changes. Several days takes a plan. Without power for a month takes the kind of preparation in a 30-day grid-down plan. The difference is mostly stored supplies, not equipment.
| Outage length | What you need |
|---|---|
| Up to 1 day | Flashlights, a charged power bank, a closed fridge, a radio |
| 2 to 3 days | Cooler and ice or a power station for the fridge, stored water, shelf-stable food, a CO alarm, a plan for medicine |
| About a week | Water at 1 gallon per person per day, a warm or cool room plan, a sanitation plan, fuel or solar for recharging |
| A month | The full 30-day plan: water treatment, long-term food, heat, sanitation, communications |
Your own limits depend on your home's heating, water source and medical needs. The readiness score asks those questions and shows which system will run out first in your house.
Gear that stretches the clock
These existing research-based picks extend the shortest clocks: the fridge, water, information and phones. Specs are from manufacturer pages; we do not test products.
No. 1Power station
Anker SOLIX C1000 Portable Power Station
Best for: Running a fridge, lights, phones and a CPAP through a one- or two-day outage
- 1,056 Wh capacity (up to 2,112 Wh with the matching expansion battery)
- 1,800 W continuous / 2,400 W surge AC output
- LiFePO4 battery chemistry
- 6 AC outlets
- 28.44 lb
Tradeoff
- At about 28 lb it is a carry-to-the-car unit, not a grab-and-go bag item.
No. 2Water storage
Reliance Jumbo-Tainer 2.0, 7 Gallon (08630-03)
Best for: Rigid, refillable storage you can rotate
- 7 gal / 26 L
- 15.3 × 8.5 × 18.0 in; 2.9 lb empty
- Food safe: LFGB certified and FDA compliant
- PFAS- and BPA-free
- Leak-proof hideaway spigot; dual handles
Tradeoffs
- Reliance does not list it as stackable
- About 58 lb when full (7 gal × ~8.3 lb plus container)
No. 3Food safety
Rubbermaid Commercial Refrigerator/Freezer Thermometer (FGR80DC)
Best for: Checking both the 40°F and 0°F thresholds
- Range −20°F to 80°F; reads °F and °C
- Easy-to-read dial; hangs or stands
- NSF listed
- 3-year limited warranty
Tradeoffs
- Analog dial without safe-zone markings
- No alarm or temperature log
No. 4Emergency radio
Midland ER310 Emergency Crank Weather Radio
Best for: A household weather radio with several ways to stay powered
- Power: solar, hand crank, 3,500 mAh rechargeable Li-ion, or 6 AA batteries
- NOAA weather band; alerts sound when issued on your local channel
- LED flashlight with SOS beacon
- USB output to top up a phone
Tradeoffs
- Midland notes the design dates to the early 2000s and may not charge newer phones (iPhone X and later) reliably. Weather alerts are not SAME county-coded.
- Midland's FAQ notes solar tops up a charged battery rather than reviving a dead one
- Micro-USB charging rather than USB-C
Frequently asked questions
- How long can you go without power?
- A household can go about 4 hours before refrigerated food is at risk (CDC) and about a day before refrigerated medicine should be replaced (Ready.gov). With stored water, safe heat or cooling, a CO alarm and shelf-stable food, a prepared household can manage for weeks. The limit is set by your weakest system, often water on a well or a medical device.
- How long can a refrigerator go without power?
- About 4 hours with the door closed, according to CDC and FDA. A full freezer holds a safe temperature for about 48 hours, and a half-full one about 24 hours. Use a thermometer to decide what to keep: refrigerated perishables above 40°F for 4 hours or more should be thrown out (FDA).
- How long can we survive without electricity?
- Electricity itself is not a survival need; water, safe temperatures and food are. A household with stored water, a warm or cool room and shelf-stable food can ride out a long outage. The main dangers are cold, heat and carbon monoxide from generators and heaters used indoors.
- How long before pipes freeze without power?
- It depends on outdoor temperature, insulation and where pipes run. Texas A&M AgriLife Extension says pipes can freeze and burst when it is 20°F or below outside, starting with those in attics, crawl spaces, garages and exterior walls. Open cabinet doors so room air reaches the plumbing, and shut off and drain the lines if the house will be left unheated.
- Can you live without power for a month?
- Yes, with preparation: a month of water storage or treatment, long-term food, a safe heat source in winter, a sanitation plan and a way to recharge lights and radios. Our [30-day grid-down plan](/guides/grid-down-30-day-plan) lays out quantities.
Sources
- CDC, What to Do to Protect Yourself During a Power Outage, August 26, 2026.
- U.S. Food and Drug Administration, Food and Water Safety During Power Outages and Floods, current as of March 5, 2024.
- Ready.gov (FEMA), Power Outages, updated June 4, 2026.
- Ready.gov (FEMA), Water, accessed October 27, 2026.
- U.S. Food and Drug Administration, Information Regarding Insulin Storage and Switching Between Products in an Emergency, content current as of September 28, 2026.
- U.S. Environmental Protection Agency, Incident Action Checklist: Power Outages, 2019.
- Texas A&M AgriLife Extension, Texas Extension Disaster Education Network, Winter Storms: Preventing and Thawing Frozen Pipes, 2008.
- Texas Department of State Health Services, February 2021 Winter Storm-Related Deaths – Texas, December 31, 2021.
- Ready.gov (FEMA), Extreme Heat, updated July 16, 2026.
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