Generac Generator Installation & Service
Holmdel, NJ.

Holmdel in the Census numbers

The U.S. Census ACS 2020-2024 5-year estimates count 17,436 residents in Holmdel Township, with a median home built in 1988. About 92 percent of homes are owner-occupied, and 77 percent are single-family detached.

A 1988 median build year means the panel dates from that period or later, and loads may have been added since. A second air conditioning zone or an electric vehicle charger, for example, may have been added to the original panel. The first step in a generator project is to read the panel and list what has been added.

Heating follows the gas pattern across Monmouth County. About 92 percent of Holmdel homes heat with utility gas, 2 percent with bottled gas (propane), and 2 percent with fuel oil. A natural gas generator is the usual starting point and a propane unit is the exception.

Reading the Building Department's rules

The New Jersey Uniform Construction Code requires a construction permit before constructing or altering (N.J.A.C. 5:23-2.14). Holmdel adds a practical layer by listing generators among projects that require plans and by running its permits through the SDL portal. The application is filed online, and the plan set has to be ready to attach.

The licensing rule matters most at the plan stage. For a standby generator the electrical work, the gas piping, and the mechanical connections are separate disciplines. Among contractors, each plan has to come from one licensed in that discipline, because the township's FAQ says home improvement contractors may not draft plans for one- and two-family homes. An architect or engineer can also prepare plans. Ask for a written statement of who prepares each part before signing anything.

This site offers a free on-site assessment with a written load calculation, and permits and inspections are handled as part of an installation. Confirm with the Building Department exactly which forms and plans it expects for a generator, since a township can change its checklist.

What goes in the plan set

A plan set for a standby generator is a short list of documents. The load calculation under NEC Article 220 shows that the unit is sized for the house, or that automatic load management is in use. A one-line or riser diagram shows how the generator, transfer switch, and panel connect. The spec sheets for the generator and the transfer switch identify the equipment.

The gas side adds its own drawing. A gas riser or isometric diagram lists pipe size, material, run length, and the BTU load, and the piping is pressure tested. Some towns want the gas test to pass before the electrical final inspection. If corrugated stainless steel tubing is used, installer certification and bonding are required.

For a propane unit at an existing one- or two-family house, a new LP vapor installation under 2,001 gallons water capacity falls under the local Mechanical Subcode, according to DCA Bulletin 09-1 as revised in July 2026, which cites N.J.A.C. 5:23-3.4(d). The local office has jurisdiction for containers of 2,000 gallons aggregate or less.

Gas service from NJNG

New Jersey Natural Gas serves Holmdel, and the utility's process starts with a generator inquiry form submitted before the generator is bought. NJNG replies within 15 business days. If the meter or service line needs an upgrade, charges can apply and the work can take about six weeks.

The standard delivery pressure is 8 inches water column, and NJNG can supply 2 PSIG on request with the contractor installing a step-down regulator. Elevated pressure may be necessary above 24 kW or when the generator sits more than 75 feet from the meter. Measure the route from the meter to the intended pad before choosing a spot, because the distance feeds directly into pipe sizing.

Generac's air-cooled home standby line runs from 10 to 28 kW, and the 28 kW model is rated 25 kW on natural gas. Where a house is near the top of the load calculation, that natural gas derating is worth knowing before a size is chosen.

Isaias, the county, and a Holmdel plan

Isaias reached Monmouth County on August 4, 2020. At its peak about 701,018 JCP&L customers were without power, and the NJ BPU staff report of November 2020 calls it second only to Sandy in JCP&L outages. JCP&L's Central Region took the brunt, the most statewide damage was in Monmouth, Morris, and Union counties, and full restoration came around August 11.

Those are regional statements, and this page does not claim a Holmdel-specific outage count. Sandy, in October 2012, left about 330,000 JCP&L customers still without power on November 5, most of them in Morris, Monmouth, and Ocean counties. Both storms point to the same planning assumption: restoration can take days.

Whatever the cause of an outage, a generator connected without a transfer switch can backfeed utility lines and endanger lineworkers, a warning from both the DCA and JCP&L. The automatic transfer switch is part of the system, not an accessory.

Cost ranges before an estimate

Generac says a typical home standby installation runs $8,000 to $16,000 including the generator, with installation taking hours and preparation taking weeks. HomeGuide, in December 2025, lists $6,000 to $11,000 as an average installed cost and $9,500 to $24,000 for systems over 20 kW or with long runs, plus $600 to $2,500 for an automatic transfer switch and $200 to $650 a year for maintenance.

All of those are published national ranges, not a quote from us. In Holmdel the plan preparation, the SDL permit filing, and the NJNG inquiry sit in the weeks of preparation, so the calendar matters as much as the price. A free on-site assessment gives a written load calculation and a number for the house itself.