Smoke & CO Alarm Coverage Calculator
Recommended smoke alarms
5
= 2 level(s) + 3 bedroom(s)
Recommended CO alarms
2
1 per level, outside sleeping areas
Estimated equipment cost (basic)
$90 – $258
Educational estimate based on NFPA 72 placement rules. Confirm counts and local code with a qualified professional.
How This Calculator Works
This calculator applies the placement minimums from NFPA 72, the National Fire Alarm and Signaling Code:
Formula
- Smoke alarms = number of levels + number of bedrooms (one per level, one inside each bedroom)
- CO alarms = number of levels (one per level, outside sleeping areas)
- Equipment cost = (smoke count × unit price) + (CO count × unit price), shown as a low–high band using typical 2024–2026 US retail prices
Why It Matters
NFPA research shows working smoke alarms cut the risk of dying in a reported home fire by about 55%. CO is called the "invisible killer" because it is odorless and colorless — alarms are the only reliable detection. Correct placement is as important as owning the devices.
Sources & Data Timeliness
- National Fire Protection Association — NFPA 72, National Fire Alarm and Signaling Code (current edition 2024)
- NFPA — Smoke Alarms (fire-death reduction statistic)
- Unit price bands reflect typical US retail ranges (First Alert / Kidde) observed in 2024–2026; verify current prices with retailers.
Frequently Asked Questions
How many smoke alarms does my home need?
Per NFPA 72 (National Fire Alarm and Signaling Code), install at least one smoke alarm on every level of the home, one inside each bedroom, and one outside each separate sleeping area. Our calculator adds the level count to the bedroom count to estimate the minimum number of smoke alarms for typical layouts.
Where should carbon monoxide (CO) alarms go?
NFPA and the ICC require CO alarms on every level and outside each sleeping area. For most homes, one CO alarm per level placed outside the bedrooms covers that level. Homes with bedrooms spread across multiple levels generally need one CO alarm per level.
Do smoke alarms really reduce fire deaths?
Yes. According to NFPA research, working smoke alarms reduce the risk of dying in a reported home fire by about 55%. Placement and working batteries matter as much as the number of units.
Should I use hardwired or battery alarms?
Hardwired, interconnected alarms are required by many building codes for new construction and offer the benefit of all alarms sounding together. Battery and 10-year sealed units are common in existing homes. Check your local jurisdiction — hardwired installs need a licensed electrician.
Related Calculators
Disclaimer
This calculator provides a planning estimate based on NFPA 72 minimum placement rules and typical retail price ranges. It is for educational purposes only and is not a substitute for a professional assessment, a fire-safety inspection, or your local building code. Always confirm requirements with your local authority having jurisdiction (AHJ) and a licensed electrician before purchasing or installing alarms.