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title: "Heat Pump + Power Outage: What Actually Happens and How to Prepare for Kootenay Winters" description: "What happens to a heat pump when the power goes out, how to size a generator or battery, and the wood-stove and insurance angles every Kootenay homeowner should think about before the next storm." slug: heat-pump-power-outage-prep-kootenays publishedAt: 2026-04-26 category: local

Heat Pump + Power Outage: What Actually Happens and How to Prepare for Kootenay Winters

Last updated: 2026-04-26

After every multi-day Kootenay outage — atmospheric rivers, wind storms, ice on the lines — the same question shows up in our inbox: if I switch to a heat pump, am I going to freeze the next time the lights go out?

Honest answer: no power means no heat pump — but it also means no gas furnace blower, no pellet stove auger, and no electric baseboard. The grid going dark in February is a problem for almost every heating system in BC. The heat pump is not uniquely vulnerable. It does reframe the backup conversation, because heat pumps run on electricity exclusively — the old plan of "keep the gas furnace running" becomes "keep this one electrical load alive."

What happens to a heat pump the moment the power goes out

Nothing dramatic. The compressor stops, the indoor blower stops, and the system sits idle waiting for utility power to return. Modern inverter compressors do not store energy or hold a charge — zero output until line power comes back.

Two practical consequences. The house starts cooling at whatever rate the envelope allows — a tight 1990s build loses heat slowly; a 1920s Nelson cottage with original lath-and-plaster walls loses it fast. And when power restores, the unit may run a defrost cycle or startup sequence before delivering useful heat. More on that toward the end.

If you have a gas furnace today, the same outage stops it too — the blower fan, ignition controls, and thermostat all need household electricity. A 95% efficient condensing furnace is as dead during an outage as a heat pump. The exceptions are a gravity-vented gas fireplace or a wood stove.

The Kootenay default: a wood stove in the corner

Across Nelson, the Slocan Valley, the Kootenay Lake shoreline, and the rural pockets around Castlegar, the most common backup-heat answer is also the oldest one. A wood stove needs no electricity, no fuel deliveries during a storm, and no tuning. A modern EPA-certified unit puts out 30,000 to 60,000 BTU/h — enough to hold one floor of a typical Kootenay home above 15°C through a multi-day outage while the rest stays at "pipes don't burst" temperatures.

Most homeowners we talk to are not planning to remove the wood stove when they install a heat pump. The full picture — rebate stack, honest application handling — lives in our heat pump and wood stove guide.

Retrofitting a wood stove from scratch is real money — $4,000 to $8,000 for an EPA-certified stove and a Class A chimney install in the Nelson area. Some homeowners do it. Many reach instead for a generator or a battery.

Generator sizing for a heat pump

Two numbers matter: running watts and starting (surge) watts.

A 2-ton ductless mini-split runs around 1,500 to 2,500 watts at moderate cold. A 3-ton ducted system pushing through a winter night might pull 4,500 to 6,500 watts continuous. Add the blower, a defrost cycle (briefly adding 1,500 to 3,000 watts of resistance on some units), and household essentials, and a 3-ton heat pump plus fridge and lights lands in the 5 to 8 kW range continuous.

The harder number is surge. Older fixed-speed compressors start with a brief 8 to 15 kW spike — enough to trip an undersized generator. Modern inverter-driven heat pumps ramp up smoothly and start under 2 kW peak. The difference matters a lot when generator-shopping.

Heat pump	Running watts	Surge (legacy)	Surge (inverter)	Recommended generator
1.5-ton ductless single-zone	1,000 – 1,800 W	6,000 – 10,000 W	< 2,000 W	5 kW inverter / 8 kW legacy
2-ton ductless	1,500 – 2,500 W	8,000 – 12,000 W	< 2,500 W	5 – 6 kW inverter / 10 kW legacy
3-ton ducted	4,500 – 6,500 W	12,000 – 18,000 W	< 4,000 W	8 – 10 kW inverter / 15 kW legacy
4-ton ducted	6,000 – 8,500 W	15,000 – 22,000 W	< 5,500 W	12 kW inverter / 18 – 20 kW legacy

Soft-start kits ($300 to $600 installed) are aftermarket capacitor packs that smooth compressor inrush on legacy units and can drop a 12 kW surge to under 4 kW. Best dollar-for-dollar upgrade for an existing non-inverter heat pump. For new inverter-driven equipment from Mitsubishi, Fujitsu, or Daikin, soft-start is essentially built in.

Portable open-frame generators in the 8 to 12 kW range run $1,500 to $4,000 retail. Standby propane or natural gas generators with automatic transfer switches run $8,000 to $15,000 installed. Portable is fine if you are home; standby is the call if you travel.

Battery backup for short outages

For 1 to 3 day outages — most of what the Kootenays actually sees — battery storage is increasingly viable. A Tesla Powerwall 3 stores 13.5 kWh usable. EcoFlow DELTA Pro Ultra stacks to 30 kWh and beyond. Bluetti and Anker offer portable 3 to 10 kWh units you can wheel into the living room and plug a single mini-split head into.

A 2-ton inverter mini-split in conservation mode (one room at 18°C, rest at 8°C) draws 800 to 1,200 W continuous, 19 to 29 kWh daily. A 13.5 kWh Powerwall runs that load 11 to 17 hours; two Powerwalls doubles it. Rooftop solar helps in shoulder seasons but contributes very little during a January Kootenay outage — short days, low sun angle, and frequent overcast typically mean solar nameplate output of 15% or less in mid-winter, so plan storage capacity as if the panels are not there.

Cost: Powerwall 3 installed runs $15,000 to $20,000 in BC; portable 5 to 10 kWh units run $2,500 to $7,000. No residential battery rebate in BC yet at the scale of California's SGIP.

The "two zones, one head" trick

The most underrated outage-prep move on a budget: install at least one single-zone ductless head alongside (or instead of) a fully ducted system, and treat that one head as the survival zone.

A single-zone Mitsubishi or Fujitsu head in the main living room runs 600 to 1,200 watts in cold-climate conditions — a load a 3 kW portable inverter handles easily, or a 5 kWh battery covers for several hours. The rest of the house drops to "pipes don't burst" temperature, the family sleeps in the living room, and you ride out a 48-hour outage without a 12 kW standby genset. The full configuration tree is in our single-zone vs multi-head vs ducted guide.

The home insurance / frozen pipes angle

Most BC home insurance friction during outages comes from one specific scenario: deep cold, the grid down for more than a day, the house cools below freezing, and pipes burst. Claims in that scenario routinely run $20,000 to $80,000.

Insurers ask about backup heat for exactly this reason. A heat pump alone does not cover the case. A retained baseboard plus a generator does. A wood stove does, no electricity required. The full picture — the three patterns BC insurance policies actually fall into and what to ask your broker — is in our home insurance and backup heat guide.

Short version: if you are removing baseboards as part of a heat pump install, ask your broker in writing whether your policy still covers pipe-burst from outage-related freeze. Some carriers say yes with a documented emergency heating plan. Some say no. The answer matters before the install, not after.

Do not bring a portable propane heater inside

Every winter in BC, someone dies of carbon monoxide poisoning from an unvented propane or kerosene heater run indoors during an outage. "Indoor-safe" buddy heaters are rated for short, well-ventilated use — not for heating a closed bedroom for eight hours overnight. Combustion produces CO whether the unit is "indoor-rated" or not.

If a portable propane heater is your only backup, treat it as a single-room, eyes-open, doors-cracked, CO-detector-running tool. Do not run one while sleeping. The Government of BC carbon monoxide page is the cleanest local source.

A battery-backed CO detector on every floor — including basement and bedroom level — is a $40 non-negotiable for any plan involving combustion appliances.

Public Safety Power Shutoffs — coming to BC?

Public Safety Power Shutoffs (PSPS) — utilities pre-emptively de-energizing lines during high-wildfire-risk weather — are a California reality that has not arrived in BC at the same scale. BC Hydro and FortisBC both have wildfire mitigation plans and both have de-energized lines during localized fire emergencies. A multi-day, regional, weather-forecast-triggered PSPS hasn't happened — yet.

The trajectory is real. Plan as if a 24- to 72-hour summer shutoff during fire season is possible within the next few years, particularly for homes on the wildland-urban interface. The same generator or battery setup that covers a January wind storm covers an August wildfire shutoff — and the heat pump in summer mode is a smoke-filtration tool, covered in our wildfire smoke defense article.

What to do after the power restores

The first thing the heat pump does when power returns is not "produce heat." Many units run a defrost cycle, pressure equalization, or a soft inverter restart — during that 5 to 30 minute window the air from the indoor head can be tepid or briefly cool. Normal. Do not slam the thermostat to 30°C.

In a ducted system, the unit may run resistance backup heat for the first 30 to 60 minutes to bring the house back to setpoint. Also normal. Where homeowners get hurt is having backup heat lockout misconfigured; see the common mistakes piece for the failure pattern.

If after an hour the system is still blowing cool air or showing an error code, that is a service call. A surge protector at the outdoor disconnect ($100 to $200 installed at original install) is cheap insurance against voltage sags during restoration.

Phone charging, freezer hierarchy, pellet stove fans

When running on a small generator or partial battery, household triage usually goes:

1. The heat pump head keeping the survival room above 15°C
2. The fridge, on a deep cycle (run two hours, off two hours)
3. The freezer (well-packed freezers hold 48+ hours unopened — usually low priority)
4. Phone and laptop charging
5. The pellet stove combustion fan, if that is your real heat source
6. Lights, TV, everything else

A 2 kW portable inverter handles 1 through 5 on rotation. A 5 kWh portable battery handles 1 through 4 for an evening if disciplined. The mistake is trying to run the whole house and exhausting fuel or storage in eight hours.

Pellet stoves need household electricity for the auger and combustion fan. Without electrical backup, a pellet stove during an outage is a decorative object. A wood stove is the only "needs no power, produces real heat" option.

Where Kootenay homeowners typically land

• Working wood stove already in place — that is your outage plan. WETT inspection if your insurer wants one, chimney clean before cold months. Spend the generator money on a small inverter unit ($600 to $1,200) for fridge, phone, and a heat pump head in moderate-cold outages.
• No wood stove, fully electric home — install at least one single-zone ductless head as part of the heat pump project, paired with a 5 to 10 kWh portable battery or a 5 kW inverter generator. Covers 80% of realistic outages.
• Deep-cold concern, no wood stove, budget available — standby propane generator with automatic transfer switch, sized for the heat pump and essentials.
• Gas-furnace-primary, considering a heat pump — outage math does not change; both systems need household power. Dual-fuel hybrid keeps the gas furnace as cold-snap and outage backup (gas-furnace economics piece).

FAQ

Will a heat pump break if power goes out suddenly? No. Modern inverter compressors are designed for clean power cycling. The risk is voltage sags during restoration, which is what a surge protector at the disconnect handles.

Can I run my heat pump on a 3,500-watt portable generator? For a single-zone ductless unit with a modern inverter compressor, often yes. For a 3-ton ducted system, no — running watts alone exceed the generator's continuous rating before surge.

Do soft-start kits work on every heat pump? Most older fixed-speed and PSC-motor units, yes. Modern inverter-driven equipment from Mitsubishi, Fujitsu, and Daikin has soft-start behavior built in — kit usually unnecessary.

How long can my house stay above freezing without any heat? A 1990s Nelson home with R-20 walls: 30 to 60 hours at -10°C outside before interior temperature reaches 5°C. A 1920s envelope without retrofit insulation: 8 to 16 hours. Insulation upgrades — attic, walls, basement — improve outage resilience as much as daily efficiency.

Is there a rebate for residential battery storage in BC? Not at residential scale as of this writing. FortisBC and BC Hydro have demand-response programs aimed at commercial customers. Watch for changes.

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Kootenay Energy matches homeowners with installers who size heat pumps with the outage and cold-climate realities of the region in mind — soft-start, single-zone-as-survival-room, and retained-backup conversations the average city installer skips. We don't sell generators or batteries; our job is to keep the heat pump install from blindsiding the resilience plan you already have. The calculator takes two minutes. Related reads: heat pump and wood stove together, home insurance and backup heat, cold-climate performance in Kootenay winters.

External authority: Government of BC carbon monoxide safety, BC Hydro outage preparedness, FortisBC emergency preparedness.