Smoke and Carbon Monoxide Detectors: Placement, Outages and Safe Heat

How many alarms do I need?

NFPA smoke: every bedroom, outside sleeping areas and every level. NFPA CO: outside sleeping areas and every level.

Levels incl. basement (L)Bedrooms (B)Separate sleeping areas (S)Count alarm positions

6 smoke positions · 3 CO positions, before merging overlaps.

Smoke = B+S+L · CO = S+L

Worked example and placement assumptions

Example: two levels, three bedrooms and one sleeping area give six smoke and three CO points. Where three positions coincide and manuals permit, use three combos plus three smoke alarms.

Mark positions, merge permitted overlaps and subtract working alarms. Check manuals for placement near fuel-burning appliances or an attached garage; no fixed extra count is added. Follow local requirements.

Printable placement checklist

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Placement: NFPA smoke / NFPA CO. Battery backup and replacement: CPSC winter guidance. Check the manufacturer's instructions for your model.

1. Walk the house

• Put a smoke alarm in every bedroom.
• Put smoke and CO alarms outside each separate sleeping area.
• Cover every level, including the basement, with smoke and CO alarms.
• Mount smoke alarms on the ceiling or high on a wall; keep smoke alarms at least 10 ft from a cooking appliance.
• Review placement near an attached garage and fuel-burning appliances in the alarm manual; follow the stated mounting distances and location.
• Confirm battery power or working battery backup for an outage; check interconnection compatibility before adding an alarm.

Record the purchase gap

Your inventory

Levels ____ · Bedrooms ____ · Sleeping areas ____

Final mounting points after checking overlap: ____

Smoke-only ____ · CO-only ____ · Combo ____

Working alarms to keep ____ · Units to add or replace ____

Monthly test and replacement record

Test and replacement dates

Monthly test / annual non-sealed battery change: CPSC. Smoke alarm replacement at ten years: NFPA. CO replacement: manufacturer.

Location / model: ____________________________

Manufactured / installed: _____________________

Monthly test date / result: ___________________

Next test / person responsible: _______________

Replaceable battery changed / next due: __________

Alarm replacement date from label/manual: ________

Recall check / action needed: __________________

1. Choose alarms by your home

NFPA recommends interconnected smoke alarms. Cover every required position with compatible units; have a qualified electrician check hardwired installations.

X-Sense SC07-W

Best for: Battery-powered homes where compatible alarms sound together.
Skip if: You need to join a hardwired system.

• 10-year sealed battery
• Up to 18 linked alarms
• No Wi-Fi needed

Check price at AmazonCheck price at X-SenseX-Sense

X-Sense SC07

Best for: One room or a small apartment needing an independent alarm.
Skip if: Your installation requires interconnected alarms.

• 10-year sealed battery
• Standalone
• LCD display

Check price at AmazonCheck price at X-SenseX-Sense

First Alert SC5

Best for: Existing compatible hardwired or Nest Protect homes.
Skip if: You need a battery-only installation.

• 120 V + battery backup
• Voice with location
• Wi-Fi + app

Check price at AmazonCheck price at First AlertFirst Alert

First Alert CO410

Best for: Extra CO coverage on AA batteries.
Skip if: This position also needs smoke detection.

• 2 AA batteries
• Backlit display
• Peak memory

Check price at AmazonCheck price at First AlertFirst Alert

Kidde KN-COPP-3

Best for: Plug-in CO coverage with battery backup.
Skip if: You need smoke sensing or interconnection.

• 120 VAC plug-in
• 9 V backup
• No interconnection

Check price at AmazonCheck price at KiddeKidde

Sensor, certification and model notes

X-Sense SC07-W and SC07: photoelectric smoke and electrochemical CO sensing. X-Sense lists ETL/UL 217; the verified Amazon listings specify UL 2034. SC07-W links up to 18 compatible X-Sense wireless alarms by radio; SC07 is standalone, without interconnection, Wi-Fi or a base. Neither has Wi-Fi or an app. Check manufacture and replacement dates.

First Alert SC5 (SMCO600NV-AC): works with and replaces Nest Protect and interconnects with compatible alarms. First Alert states conformity to UL 217 10th Edition. Uses the First Alert app.

First Alert CO410: electrochemical CO sensing and an end-of-life warning. Its two AA batteries operate without grid power.

Kidde KN-COPP-3: electrochemical CO sensing, a display updated every 15 seconds and peak memory. Kidde lists KN-COP-DP-10YL as the successor; confirm the model at checkout.

Specifications checked Oct 16, 2026; official sources are linked above.

2. Power-outage mode: what keeps working?

CPSC recommends battery-powered alarms or working battery backup.

3. Safe heat this winter

With grid power

CPSC says to keep space heaters at least three feet from combustible materials, plug directly into a wall outlet and turn them off before sleeping. Never use an extension cord or power strip. Follow those rules even with automatic shutoff.

Vornado MVH

Best for: Wall-outlet heat while awake, with grid power.
Skip if: You need an outage or overnight heating plan.

• 1500/750 W · 120 V
• Tip-over switch
• Two-stage shutoff

Check price at AmazonCheck price at VornadoVornado

First Alert HOME1

Best for: Home fire plans needing this rating.
Skip if: You need protection for large-volume cooking grease.

• UL 1-A:10-B:C
• Professionally rechargeable
• 5.4 lb

Check price at AmazonCheck price at First AlertFirst Alert

The MVH has three settings and a mechanical thermostat. The HOME1 (FE1A10GR) rating covers wood, paper, fabric, flammable liquids and energized electrical equipment; have a certified professional recharge it. Use the alarm response steps when an alarm sounds.

During a power outage

Use dry layers and blankets, gather supplies in one room, and plan a reachable heated destination if staying home is unsafe. Follow NWS cold guidance and Ready.gov outage guidance. Use the winter outage checklist, 72-hour kit and power-outage kit.

Generators: outside, at least 20 feet from home, exhaust directed away, per CPSC. Never use one in a house, garage or basement; open doors and windows do not provide enough ventilation. Compare generators and power stations before choosing.

CPSC recommends flashlights instead of candles. Reserve battery power for light, phones and radios, never resistive heaters: their high draw drains stored energy. Size loads using the power-station guide.

Goal Zero Lighthouse 600

Best for: Shared light with a charging plan.
Skip if: Working lights already cover the room.

• Rechargeable
• 600 lumens
• USB power output

Check price at AmazonCheck price at Goal ZeroGoal Zero

EcoFlow RIVER 3 Plus

Best for: Compact light, phone and radio backup.
Skip if: You need to run a resistive heater.

• 286 Wh
• 600 W output
• 10.4 lb

Check price at AmazonCheck price at EcoFlowEcoFlow

BLUETTI Elite 200 V2

Best for: Larger light, phone and radio reserves.
Skip if: A smaller reserve suffices or carrying it is impractical.

• 2,073.6 Wh
• 2,600 W output
• 53.4 lb

Check price at AmazonCheck price at BLUETTIBLUETTI

Midland ER310

Best for: Receiving weather information during an outage.
Skip if: You already have a working receiver.

• NOAA + AM/FM
• Rechargeable battery
• Hand-crank backup

Check price at AmazonCheck price at MidlandMidland

Compare lanterns and headlamps and emergency radios. Compare remaining supply gaps with My Patriot Supply’s Winter Prep collection.

4. If an alarm sounds

Smoke: get out and stay out. Follow USFA guidance and your escape plan.

CO: move to fresh air, account for everyone and call for help from outside. Wait for emergency responders, following NFPA guidance.

5. Test, replace and check the label

• Test monthly, per NFPA and CPSC.
• Replace non-sealed batteries annually, following CPSC and the manual. Follow the replacement instructions for sealed units.
• Replace smoke alarms at ten years, per NFPA; CO alarms follow the manufacturer’s interval. Record manufacture and replacement dates separately from the warranty.
• Check your model for recalls at CPSC Recalls.
• Have fuel-burning heating systems professionally inspected annually, per CPSC.

X-Sense label check: its notice says some older SC07/SC07-W distributor units used UL 217 6th Edition, superseded by 9th Edition on June 30, 2024. X-Sense says there is no safety risk and offers a free upgrade for purchases from June 30, 2024 through Dec 31, 2025. It lists current SC07/SC07-W models under 9th Edition. Check your unit’s label and the upgrade window.

Frequently asked questions

Hardwired or battery alarms?

Match the installation and interconnection system. Battery units work without mains power; hardwired units need backup. NFPA calls for a qualified electrician for hardwired installation.

Combo detectors or separate smoke and CO alarms?

Use combos at positions allowed by their manual. Cover bedrooms with smoke alarms; put CO alarms outside sleeping areas and on every level. Follow NFPA smoke and CO rules to plan the positions.

Should a CO detector be high or low?

Follow its mounting instructions. NFPA calls for CO alarms outside sleeping areas and on every level; the model’s manual determines mounting height.

Does a CO detector work during a power outage?

Battery units operate independently; hardwired and plug-in models need backup. CPSC recommends battery power or backup. App alerts need Wi-Fi and internet.

Can I sleep with a space heater on?

CPSC says to turn it off before sleeping, including models with tip-over protection and automatic shutoff.