New York City Mandates Natural Gas Sensors, Installation Required by May 1, 2025

Despite the city’s push to electrify all buildings, it is not taking its eye off gas and its potential dangers. Adding to the city’s bewildering maze of local laws and deadlines, there’s a new one looming. If you have a gas oven — or any gas appliance such as clothes dryers or fireplaces — in your apartment, you must install a natural gas sensor by May 1, 2025. This rule, part of Local Law 157, is intended to enhance safety by detecting leaks early. However, it places another compliance burden on boards, and its specific requirements on how and where the devices must be installed are both complicated and costly.

THE BACKSTORY

Like carbon monoxide, natural gas is colorless and odorless, making leaks potentially deadly. The natural gas sensor law, which applies to all residential buildings in New York City,  was one of multiple gas safety measures passed by the City Council in 2016 after two fatal gas explosions at two apartment buildings in East Harlem and the West Village. Despite the fact that the leaks causing the explosions did not stem directly from gas appliances, as well as testimony from the Department of Buildings (DOB) claiming more research was needed, the ruling was approved. “When there’s a risk, no one wants to say the risk is exaggerated,” says Jerry Kestenbaum, founder of Aware Buildings, a company providing property management solutions that include sensor technology. Out of an abundance of caution, LL157 mandated both carbon monoxide and gas sensors, but delayed implementation of natural gas alarms until a national standard was established. 

Last year, the National Fire Protection Association issued that standard, prompting the DOB to implement the rule, which requires the installation of natural gas alarms at or close to ceiling height and within three to 10 feet of any gas-burning appliance. Gas ovens are the obvious targets, but gas dryers and fireplaces — most commonly found in new construction — and even gas-fed packaged terminal air conditioner units installed through walls are included. According to Kestenbaum, the rules will have a significant impact, requiring up to four million sensors to be installed at a total cost of $250 million.

A LACK OF OPTIONS

But there’s a wrinkle with the new mandate that will make it difficult for boards to keep installation costs down — the lack of choice on natural gas alarms. Plug-in models exist, but mounting them on or near the ceiling would require hiring an electrician to install a new socket or run an electric cable up from an existing low level socket, which may not even be close to the gas appliance itself. And currently, there’s only one certified natural gas sensor on the market that doesn’t require electricity and has a long-term battery life, which would be much easier and less costly to install as the law requires.  

That code-compliant sensor is DeNova Detect, manufactured by a subsidiary of Japanese-owned New Cosmos Electric, and is available from only three distributors in the U.S. — ProSentry, F&F Supply and New Cosmos U.S.A. The battery lasts 10 years and the alarm retails at around $70, significantly more than plug-in sensors from brands like Kidde and First Alert that can cost as little as $20. Some come with extension wires that can connect the device to a nearby socket, eliminating the need for an electrician.

However, “the wire’s unsightly and you have to change the 9V back-up battery every few years, and most people don’t want that,” says Michael Wolfe, president of the management company Wolfe Realty Services. “We really don’t have options,” he says, summarizing the frustrations of boards, which bristle at the contradiction of being required to spend money on gas monitoring while the city is encouraging electrification. 

And it’s clearly not ideal to have a law that relies almost exclusively on one overseas manufacturer. “There’s an argument that the industry isn’t ready for this mandate until there’s at least two competing battery-operated sensors available,” says Kestenbaum, “It would certainly be preferable if a U.S. manufacturer were supplying the city with gas alarms.”

Indeed, New Cosmos Electric is poised to reap huge rewards in addition to its $25 million dollar partnership with Con Edison to install 400,000 natural gas alarms in boiler rooms across the city by 2025. This monitored version of the DeNova Detect uses a wireless network to send alerts directly to the utility company and is able to precisely pinpoint the activated sensor location. With 3.7 million apartments in New York City, 70% of which are estimated to have gas stoves, New Cosmos Electric could reap ten times as much from the new law. Because of the relatively quick deadline, American manufacturers won’t have enough time to develop a competitive product, Kestenbaum points out, adding that the city is, in essence, handing Japan a multi-million contract.

THE COSTS OF MONITORING

The minimum cost for a 100-unit building to comply with LL157 by installing unmonitored devices will be around $7,000, while a monitored system would cost around $25,000, with operating costs of between $1 and $3 per sensor per month. The simplest and most economic scenario is to have your management company buy unmonitored alarms in bulk and facilitate their installation. The monitored devices are more of a financial commitment and could impact building budgets. Peter von Simpson, chief executive officer at New Bedford Management, expects boards to bill the purchase and installation costs back to shareholders or unit-owners by increasing maintenance or common charges. Either way, A.J. Rexhepi, chief executive officer of Century Management Services, adds, “it comes out of the same pocket.”

THE CHALLENGES AHEAD

The challenges of complying with the sensor mandate could force boards into doing some complicated decision-making when it comes to other regulations. The potentially disruptive gas-pipe pressure testing inspections required under Local Law 152 — also introduced in 2016 — might push some boards to pursue electrification wherever feasible, although many pre-war buildings will find the financial burden to make the switch is cripplingly impractical. And shareholders and unit-owners may be reluctant to replace their gas stoves with electric models.

As for boards and managing companies that are considering delaying the installation of natural gas sensors in the hope that costs will come down, it’s unlikely. John Rusk, founder of ProSentry, a company providing building detection services and a supplier of DeNova Detect products, points out that there has been plenty of time for competitors to develop a rival product. “All of the manufacturers have been on notice for the last six years,” he says. “But only one kept going with the research and figured out how to make a gas detector that can last 10 years on a single battery.” And while New Cosmos Electric recently opened a factory in Mexico to meet U.S. demand for natural gas sensors, there are no guarantees that prices won’t increase.

Then there’s the question of which sensor to install. The less expensive, unmonitored sensors cannot be upgraded to the monitored networked version so it wouldn’t make economic sense to choose unmonitored gas sensors if a building has plans to upgrade to smart monitoring on the horizon. “The last thing you want to do is bulk-buy battery operated ones thinking buildings are not going to want to spend the money on monitored ones,” Rexhepi says.

Monitored devices are more expensive than unmonitored versions, but their big selling point is that they can be expanded to include other smart detection capabilities including flooding and security, a valuable and increasingly popular building management tool. “If insurance companies start to give rebates for monitoring systems, it’s an easier choice,” Wolfe says. Another advantage of smart alarms is how they alert both the monitoring company and, typically, the building super about a leak, which can avert a building-wide gas shutdown in the event of an activated sensor. “The super can isolate the gas at the shut-off valve and deal with just that apartment as opposed to the fire department shutting down the whole building,” Rexhepi says. 

With no expectations of a delay in implementing LL157, boards are left with yet more questions as they await rules about enforcement, which is being handled by NYC’s Department of Housing Preservation and Development. A HPD spokesperson says rules regarding enforcement and inspection protocols will be developed within the next few months.