Why Long Island Homeowners Are Converting from Oil to Gas
More than 40% of Long Island homes still run on heating oil — one of the highest oil-heat concentrations in the country. That made sense decades ago when oil was cheap and reliable, but the math has shifted dramatically. Heating oil on Long Island typically runs $4.00–$6.00 per gallon depending on the season, and prices swing 20–40% year over year based on crude markets and regional supply disruptions.
Natural gas, by contrast, is priced far more stably on Long Island. National Grid residential rates have held in a tighter band for over a decade, insulating homeowners from the kind of winter sticker shock oil customers routinely experience. For a typical 2,000 sq ft home burning 800 gallons of oil, that stability translates to $1,500–$3,000 in annual savings after conversion.
Beyond fuel cost, converting to gas tends to increase home value on Long Island — buyers strongly prefer gas heat, and listings with gas frequently sell faster than equivalent oil-heated homes. Gas systems also require less maintenance: no annual tank cleanings, no soot, no summer fill-ups, and no worry about a buried tank leaking into your yard and triggering a six-figure remediation bill.
Finally, gas boilers and furnaces run cleaner and more efficiently than most oil units. A 20-year-old oil boiler running at 78% AFUE can be replaced with a 95%+ AFUE gas condensing boiler — a meaningful jump in fuel economy before you even factor in the lower commodity price.
Is Natural Gas Available at Your Address?
This is the first question to answer before anything else. National Grid is the natural gas utility for Long Island, serving all of Nassau County and most of western and central Suffolk. Much of the South Shore and North Shore of Suffolk has gas mains in the street, but large portions of the East End — including most of the Hamptons, the North Fork, and parts of Brookhaven — still have no gas service at all.
You can check gas availability at your address directly on nationalgrid.com using their service area lookup, or call National Grid's new service line. Our technicians also confirm availability during free estimates by pulling up the utility map and walking your property's frontage.
If a gas main already runs in front of your house, the tap-in is usually straightforward and sometimes fully covered by National Grid under their EnergySmart promotion. If the main ends several houses down, extension fees apply — and if the nearest main is a block or more away, the extension cost can make conversion economically impractical. That is a call to make honestly, not something to force.
Total Cost Breakdown — Oil to Gas Conversion on Long Island
Conversion cost varies widely based on your specific home, existing system type, and tank situation. Here is the realistic 2026 cost range for each component of a Long Island conversion:
| Component | Cost Range | Notes |
|---|---|---|
| Gas line hookup from street | $1,500–$5,000 | National Grid sometimes covers the tap fee |
| High-efficiency gas boiler (hydronic) | $8,000–$14,000 | 95%+ AFUE, typical 2,000 sq ft home |
| Gas furnace (forced air homes) | $4,500–$9,000 | Replaces oil furnace on same ductwork |
| Oil tank removal — above-ground | $300–$800 | Basement or exterior tank, pumped + hauled |
| Oil tank removal — underground (UST) | $2,000–$5,000 | NYSDEC Part 613 regulated, soil test if leak suspected |
| Suffolk County permits | $200–$500 | Plumbing + mechanical permit required |
| Chimney liner (if needed) | $800–$2,500 | Stainless liner for Category I gas venting |
For a typical Long Island home — above-ground tank, gas main at the curb, standard boiler swap — total out-the-door cost usually lands between $9,000 and $13,000 before rebates. Homes needing underground tank removal, a chimney liner, or a gas main extension sit at the higher end of the range.
Need a quote specific to your setup? See our boiler installation service and our gas line installation service for scope details, or call for a free on-site assessment.
The Conversion Process Step-by-Step
A typical oil to gas conversion on Long Island spans 4–8 weeks from first call to finished project, though the on-site work only accounts for 3–5 days of that. Most of the timeline is permitting and utility scheduling. Here is how it unfolds:
- 1
Free in-home assessment
A technician visits, confirms gas main availability, sizes the new boiler or furnace using Manual J load calculation, checks your chimney and venting, and documents your oil tank situation.
- 2
Estimate + rebate walkthrough
You receive a detailed estimate showing equipment, labor, permits, tank removal, and any chimney work — plus a breakdown of National Grid rebates, NYSERDA incentives, and the federal 25C tax credit you qualify for.
- 3
National Grid service application
Once you approve, we submit the gas service application to National Grid. This is typically the longest step — plan on 2–4 weeks for them to schedule the street tap, trench, and meter set.
- 4
Suffolk County permits
We pull the plumbing and mechanical permits through the Suffolk County (or Nassau) building department. Underground tank removal requires additional DEC and county health department paperwork.
- 5
Oil tank removal + fuel line disconnect
On day one, the oil tank is pumped, cut up if needed, and hauled out. Old fuel lines are capped. If the tank is buried, the soil is inspected for contamination and backfilled.
- 6
New gas boiler or furnace installation
Days two and three: install the new high-efficiency gas unit, run the gas line inside the home, connect to existing ductwork or hydronic piping, install chimney liner if required, and commission the system.
- 7
Inspection + National Grid gas turn-on
Suffolk inspector signs off, National Grid turns on gas, the new system is fully commissioned, you get a walkthrough, and warranty paperwork is filed. Rebate applications are submitted on your behalf.
Oil Tank Removal — Above-Ground vs Underground
Tank removal is often the biggest surprise cost in a Long Island conversion. Above-ground tanks — basement-mounted steel or garage tanks — are straightforward. Underground tanks are a different story: they fall under NYSDEC Part 613 regulations and are monitored by the Suffolk County Department of Health Services. Here is the difference:
| Factor | Above-Ground | Underground (UST) |
|---|---|---|
| Typical cost | $300–$800 | $2,000–$5,000 |
| Regulation | Minimal — local haul-away | NYSDEC Part 613 + Suffolk Health Dept |
| Timeline | Half-day | 1–2 days |
| Soil testing | Not required | Required if contamination suspected |
| Registration | None | Must be registered with NYSDEC before removal |
| Insurance impact | Minor | Major — leaks can trigger $50k+ cleanup |
If a buried tank shows signs of leaking during removal — staining, odor, or contaminated soil — Suffolk County requires soil sampling and, in confirmed contamination cases, a remediation plan. In rare cases this pushes total tank costs past $10,000. Most tanks come out clean, but it is worth budgeting a contingency if your tank is more than 30 years old.
Available Rebates and Incentives
Rebates can meaningfully reduce the out-of-pocket cost of converting, though the landscape has shifted over the last two years as New York State accelerates its push toward electrification and heat pumps. Here is what is currently available to Long Island homeowners:
National Grid EnergySmart Rebates
Rebates of $1,200–$2,300 for qualifying high-efficiency gas boilers and furnaces (95%+ AFUE). Availability and amounts change seasonally — always verify current offers at nationalgrid.com before signing a contract.
NYS Clean Heat Program (NYSERDA)
Administered by NYSERDA, this program primarily targets heat pump conversions — but income-qualified households may access EmPower+ funding for other weatherization work that stacks with a gas conversion.
Federal 25C Tax Credit
Up to $600 for a qualifying high-efficiency gas boiler or furnace, claimed on IRS Form 5695. Heat pump systems qualify for a larger credit — up to $2,000.
NYSERDA Smart Energy Loan
Low-interest financing for energy efficiency upgrades, including eligible high-efficiency gas equipment. Terms up to 15 years, with on-bill repayment options for some borrowers.
Important note: oil-to-gas rebates have been shrinking year over year as New York State pushes toward all-electric heating. If gas conversion makes sense for your home, the economics are better now than they are likely to be in three to five years. Learn more about alternatives on our heat pump service page.
Oil to Gas vs Oil to Heat Pump — Which Is Better for Long Island?
If you are already ripping out an oil system, it is worth asking whether you should skip gas entirely and go straight to an electric heat pump. New York State is clearly steering homeowners this direction, and the incentive math has gotten aggressive. Here is the honest side-by-side:
| Factor | Oil → Gas Conversion | Oil → Heat Pump |
|---|---|---|
| Installed cost | $7,000–$18,000 | $12,000–$25,000 |
| Annual operating cost (LI) | $1,400–$1,800 | $1,200–$2,000 |
| Rebates available | National Grid $1,200–$2,300 | NYS Clean Heat up to $10,000+ |
| Federal tax credit | Up to $600 (25C) | Up to $2,000 (25C) |
| Backup heat needed | No | Yes — below 5°F on coldest nights |
| Long-term NY direction | Being phased down | State-preferred electrification path |
Our take: if natural gas is already at the curb and you want the lowest upfront cost with predictable winter heat, gas conversion is still the right answer for most Long Island homes. If you are planning to add central AC anyway, want the larger rebates, and your home has good insulation, a cold-climate heat pump is worth a serious look — it handles both heating and cooling and aligns with where New York is headed long-term.
Permits and Code Requirements on Long Island
An oil to gas conversion is a permitted job on Long Island — there is no DIY path, and any contractor who offers to do it without permits should be walked away from. Suffolk County and Nassau County have slightly different processes but similar requirements.
Suffolk County requires a plumbing permit for the gas line installation and a mechanical permit for the new boiler or furnace. Underground tank removals also require notification to the Suffolk County Department of Health Services and compliance with NYSDEC Part 613 decommissioning protocols. Inspections happen at rough-in (gas line pressure test) and final (system commissioning).
Nassau County follows a similar pattern through the Nassau County Department of Public Works and individual town building departments. Permit fees run $200–$500 depending on scope. A licensed master plumber must perform the gas work and sign the permit — that is a legal requirement, not a preference.