Smoke & CO alarms · West Orange, Montclair and Essex County
In New Jersey, hardwired smoke alarms must be replaced with hardwired alarms, not battery ones, and a one- or two-family home needs a smoke and CO alarm certificate from the town before it is sold or rented. Installed detectors cost about $110 to $410 or more each by HomeGuide's published national range. MDL Electric is a licensed electrical contractor in West Orange: call to ask about your alarms.
The short answer
When a one- or two-family home in New Jersey is sold or rented, it must have a smoke alarm on each level and outside each sleeping area, and a carbon monoxide alarm near the bedrooms when there is a fuel-burning appliance or an attached garage (N.J.A.C. 5:70-4.19). Battery alarms must be ten-year sealed units. Hardwired alarms that came with the house may not be swapped for battery ones.
Before the home is sold, leased or gets a new occupant, the owner needs a certificate from the town covering the smoke alarms, the carbon monoxide alarms and, where the home has a secondary power source, its warning label (N.J.A.C. 5:70-2.3; P.L. 2025, c.19). That 2025 law took the fire extinguisher out of the state certificate. Replacing old hardwired alarms is electrical work. MDL Electric is a licensed New Jersey electrical contractor (34EI01606200) at 4 Harrison Avenue in West Orange. Call 973.809.2339 to ask about your alarms.
Four kinds of alarm jobs
The permit rules come from the state Uniform Construction Code (N.J.A.C. 5:23-2, NJ Department of Community Affairs), and the town's construction office enforces them.
Replacing a smoke alarm with a like device is ordinary maintenance, with no permit (5:23-2.7). The new alarm has to fit the old wiring: Kidde says its adapters work only with the exact model pairs it lists, and the power goes off at the breaker first.
Installing a new fire detection device in a one- or two-family home is minor work (5:23-2.17A). The town is told before work starts, the permit application follows within five business days, and the inspection comes within three business days of the request.
Installing battery-powered smoke alarms is ordinary maintenance, with no permit (5:23-2.7). In New Jersey they must be ten-year sealed units listed to UL 217, and they may not replace hardwired alarms that came with the house.
Installing battery or plug-in CO alarms is ordinary maintenance, with no permit (5:23-2.7). A combination smoke and CO alarm puts both in one unit, at $140 to $360 or more installed by HomeGuide's range.
New Jersey rules
From the New Jersey Uniform Fire Code and P.L. 2025, c.19, read October 19, 2026. The state's matching rewrite of the fire code rules is still proposed, per the Division of Fire Safety's January 13, 2026 bulletin. Your town's fire official or construction office enforces them and may ask for more.
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| Topic | What the rule says | Section |
|---|---|---|
| Where smoke alarms go | On each level, and outside each separate sleeping area, located and maintained to NFPA 72. They do not have to be interconnected. | 5:70-4.19(a), (b) |
| Battery alarms | Ten-year sealed battery single-station alarms listed to UL 217, since January 1, 2019. | 5:70-4.19(c) |
| Hardwired alarms | A/C-powered alarms installed with the original construction or a rehabilitation project may not be replaced with battery-powered alarms. | 5:70-4.19(c) |
| Carbon monoxide | In the immediate vicinity of the sleeping areas, unless the building has no fuel-burning device and no attached garage. Battery, hardwired or plug-in, listed to UL 2034, installed to NFPA 720. | 5:70-4.19(d) |
| Secondary power source label | A home with a secondary power source must have a label within 18 inches of the main electrical panel and the electrical meter, warning of the danger of secondary power sources. The Division of Fire Safety now calls the certificate the certificate of smoke alarms, carbon monoxide alarms and secondary power source identification label compliance. | N.J.S.A. 52:27D-198.1, as amended by P.L. 2025, c.19 |
| Fire extinguisher | No longer part of the state certificate. P.L. 2025, c.19, approved February 3, 2025, removed the portable fire extinguisher from N.J.S.A. 52:27D-198.1 and 198.2. Montclair's fire department notes that fire extinguishers are no longer required. West Orange's own CCO inspection list still includes a fire extinguisher in the kitchen area. | P.L. 2025, c.19 |
| The certificate | Needed before the home is sold, leased or gets a new occupant. Not transferable. A new application is needed if the change does not happen within six months. No certificate without a UL 2034 CO alarm where one is required. | 5:70-2.3 |
| State fee | $45 more than 10 business days before the change of occupant, $90 at 4 to 10 business days, $161 at fewer than 4. A town with its own fire enforcing agency may set different fees. | 5:70-2.9(d), (f) |
| Penalty | An owner who sells, leases or lets a home be occupied without compliant alarms or the certificate faces a fine of up to $500. | N.J.S.A. 52:27D-198.3 |
Selling or renting
The same order works for a sale, a new lease or a tenant turnover.
Under the state schedule the fee is $45 more than 10 business days before closing and $161 inside four days (5:70-2.9(d)). Montclair asks for all documents at least 10 days before closing.
Press each test button. Read the date on the back. Look for a CO alarm near the bedrooms if there is a gas, oil or wood appliance or an attached garage.
Replace alarms past 10 years and any hardwired alarm that fails, with a hardwired one. West Orange notes that when repairs are needed so all alarms sound together, a licensed electrician may be required.
The certificate covers the change of occupancy named on the application. If it slips past six months, apply again (5:70-2.3).
Your town
Each town decides which office inspects and what it charges. These are the towns' own documents, read October 19, 2026.
West Orange requires a Certificate of Continued Occupancy before any home is sold or rented: $200 for a single-unit home, $275 for two units, $75 per reinspection. Its own inspection list includes smoke and CO detectors, a fire extinguisher in the kitchen area (a local item; the state certificate dropped it in 2025), exposed wiring and grounded receptacles. The Building Department's smoke and CO sheet places a smoke alarm on the basement ceiling near the stairs, by the first-floor stairway, and in the bedroom hallway no more than 10 feet from any bedroom.
Montclair's ordinance O-26-31, adopted August 11, 2026 (notice of adoption), sets the sale certificate fee at $115, $140 or $165 for a one-family home and $135, $170 or $180 for a two-family home, by whether the request comes in more than 10, 4 to 10, or fewer than 4 business days before closing. A rental change of occupancy is $75 per unit. The fire department page still lists $75, so confirm the fee with the bureau, and send documents at least 10 days before closing. Its requirements ask for a certified letter or report from a licensed electrician or licensed alarm technician stating the smoke alarms have been tested and are functioning properly.
In South Orange, Maplewood, Livingston, Verona, Bloomfield, East Orange and Orange, call the town's fire prevention bureau or construction office for its form and fee. The state schedule is $45, $90 or $161, and a town with its own fire enforcing agency may set different fees (5:70-2.9).
Hardwired alarms
Hardwired alarms run on a 120-volt household circuit, usually with a battery backup. NFPA's June 2024 report found hardwired alarms operated in 94% of home fires large enough to set them off, against 85% for battery-only alarms (NFPA, Smoke Alarms in US Home Fires).
Cost
HomeGuide's published national prices per detector, device plus installation. The labor alone runs $100 to $260 or more per unit, and electricians charge $50 to $130 an hour. Market ranges, not MDL prices.
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| Detector | What it does | Device | Installed, per unit |
|---|---|---|---|
| Ionization | Quicker on fast, flaming fires | $10 to $40 | $110 to $290 |
| Photoelectric | Quicker on smoldering fires | $20 to $70 | $120 to $330 |
| Dual sensor | Both sensors in one alarm | $40 to $100+ | $140 to $360+ |
| Combination smoke and CO | Smoke alarm and CO alarm in one | $40 to $100+ | $140 to $360+ |
| Carbon monoxide only | CO alarm | Slightly less than a combination unit | $120 to $360 |
| Smart | Wi-Fi alerts to a phone | $50 to $150 | $150 to $410+ |
Carbon monoxide and the heating season
New Jersey ties the CO rule to fuel-burning appliances and attached garages (N.J.A.C. 5:70-4.19(d)). West Orange's sheet names a furnace and a hot water heater as examples of fuel-burning appliances.
If a CO alarm sounds, leave the house and call 911. MDL services furnaces and boilers; see heating repair once everyone is safe.
Placement
New Jersey's minimum is one on each level and outside each sleeping area. NFPA recommends more, and its placement rules help an alarm work and stay quiet while you cook.
Inside each bedroom, outside each sleeping area, and on every level, including the basement ceiling at the bottom of the stairs.
A wall-mounted alarm no more than 12 inches below the ceiling. On a pitched ceiling, within 3 feet of the peak but not in the top 4 inches.
At least 10 feet from a cooking appliance, and not near windows, doors or ducts where drafts can keep smoke away.
Where MDL works
MDL works from 4 Harrison Avenue in West Orange and serves West Orange, Montclair, South Orange, Maplewood, East Orange, Livingston, Bloomfield, and the rest of Essex County, including Verona and Orange. Each town has its own fire official and fee, so tell MDL the town when you call.
Smoke and CO alarms
Call or send the form with your town, how many alarms you have, whether they are hardwired, the date on the back, and your closing or move-in date if you are selling or renting.
Smoke and CO alarm questions
Rules are quoted from the official texts linked above. Prices are published market ranges, not an MDL quote.
Only if the house already has them. N.J.A.C. 5:70-4.19(c) says A/C-powered smoke alarms installed as part of the original construction or a rehabilitation project shall not be replaced with battery-powered alarms. A house that never had hardwired alarms can pass with ten-year sealed battery alarms listed to UL 217. Either way, the town checks them before it issues the certificate the sale needs.
Six months. Under N.J.A.C. 5:70-2.3, if the sale, lease or move-in named on the application does not happen within six months, a new application is required, and the certificate cannot be transferred to someone else. Montclair's application says its certificate expires six months after the fire department inspection.
It depends on the town and on how early you apply. The state fee schedule in N.J.A.C. 5:70-2.9(d) is $45 when the request comes in more than 10 business days before the change of occupant, $90 at 4 to 10 business days, and $161 at fewer than 4. A town with its own fire enforcing agency may set different fees by ordinance. Montclair's ordinance O-26-31, adopted August 11, 2026, charges $115, $140 or $165 for a one-family sale and $135, $170 or $180 for a two-family sale (more than 10, 4 to 10, or fewer than 4 business days before closing) and $75 per unit when a rental changes occupants; its fire department page still lists $75. West Orange checks the alarms as part of its Certificate of Continued Occupancy, which costs $200 for a single-unit home and $275 for a two-unit home.
No, not where the hardwired alarm came with the original construction or a rehabilitation project. N.J.A.C. 5:70-4.19(c) forbids replacing A/C-powered smoke alarms with battery-powered ones, and West Orange's Building Department puts it plainly: a hardwired system may not be diminished by replacing it with a battery-operated system. A battery system may be upgraded to hardwired.
Not for a like-for-like swap. N.J.A.C. 5:23-2.7 lists replacing a smoke alarm or smoke detector head with a like device, and installing battery-powered smoke alarms or battery or plug-in CO alarms, as ordinary maintenance with no permit. Installing a new fire detection device in a one- or two-family home is minor work under N.J.A.C. 5:23-2.17A: the town is notified before work starts, the permit application follows within five business days, and the town inspects within three business days of the request.
A licensed electrical contractor or a licensed alarm contractor installing fire alarms, or a single-family homeowner on his or her own home. N.J.A.C. 5:23-2.15 says electrical work shall not be undertaken except by persons licensed to do it, apart from a single-family homeowner on his or her own dwelling. For fire protection equipment it requires a state certification, but not for licensed electrical contractors, licensed alarm contractors installing fire alarms, or homeowners working in their own homes. MDL Electric's New Jersey electrical contractor license is 34EI01606200.
Every 10 years from the date of manufacture, printed on the back. NFPA says all smoke alarms must be replaced 10 years after their manufacturing date, and New Jersey's State Fire Marshal tells residents the same. Kidde recommends replacing its carbon monoxide and combination alarms every 7 to 10 years, depending on the model. An alarm that keeps chirping after a new battery is at the end of its life.
In the immediate vicinity of the sleeping areas, in any one- or two-family home with a fuel-burning appliance or an attached garage (N.J.A.C. 5:70-4.19(d)). They may be battery, hardwired or plug-in, listed to UL 2034. West Orange asks for one outside the bedroom area, no further than 10 feet from any bedroom, plus one near any room with a fuel-burning appliance such as a furnace or water heater.
New Jersey's certificate rule asks for at least one on each level of the home and one outside each separate sleeping area (N.J.A.C. 5:70-4.19(a)). NFPA recommends more: inside every bedroom too, plus the basement ceiling at the bottom of the stairs. A two-story house with a basement and three bedrooms off one upstairs hall needs at least three alarms under the state minimum, and six under NFPA's advice.
Not for the resale certificate: N.J.A.C. 5:70-4.19(b) says the alarms shall not be required to be interconnected. An interconnected system that is already there has to keep working, though, and NFPA recommends interconnection because when one alarm sounds, they all sound. Interconnected alarms should come from the same manufacturer, or they may not sound together.
HomeGuide's published national range is $110 to $410 or more per detector, installed, and $100 to $260 or more for the labor alone, with electricians at $50 to $130 an hour. A combination smoke and CO alarm runs $140 to $360 or more installed. These are market ranges, not MDL prices. HomeGuide notes that existing wiring can lower the cost of replacing hardwired alarms.
Call 973.809.2339 or send the form on this page with your town, how many alarms you have, whether they are hardwired, the date printed on the back, and your closing or move-in date if you are selling or renting. MDL Electric is a licensed New Jersey electrical contractor at 4 Harrison Avenue in West Orange and also services furnaces and boilers.
Sources
All read October 19, 2026.
Next steps
The full list of MDL's electrical work: repairs, circuits, panels, EV chargers, generators, and renovations.
Learn moreBreakers that trip, dead circuits, and wiring problems found at an inspection, diagnosed before anything is replaced.
Learn moreFurnace and boiler service for the fuel-burning appliances that make a CO alarm necessary.
Learn moreThe Essex County towns MDL serves from its West Orange base.
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