You check the thermostat. Nothing. You head to the basement, stare at the furnace, and realize you have no idea where to start. It's a scenario that plays out in Nassau County homes every winter — after a Nor'easter knocks out power, or after a tank runs lower than expected and the burner shuts off.
Here's the thing most troubleshooting guides miss: restarting a gas furnace and restarting an oil furnace are not the same process. One involves a fairly straightforward reset. The other — especially if you've run out of fuel — requires an additional step that a lot of homeowners don't know about. Getting that wrong can leave you in the cold longer than necessary, or worse, damage your system.
Let's break it down clearly.
Restarting Your Furnace After a Power Outage: What Both Systems Have in Common
One of the most common misconceptions about oil heat is that the furnace runs independently of the electrical grid. It doesn't. Both gas and oil furnaces rely on electricity to power the blower motor, thermostat, and control board. When PSEG Long Island cuts out during a winter storm, both types of furnaces go down — regardless of how much fuel you have.
The good news is that for most homeowners, the post-outage restart is manageable. Once power is restored, the furnace usually needs a moment to reset its controls before it fires back up. The process is similar across both fuel types — up to a point.
How to Restart a Gas Furnace After the Power Comes Back On
When power is restored after an outage, a gas furnace will often restart on its own within a few minutes as the thermostat calls for heat and the control board cycles back up. If it doesn't, there are a few things to check before you call anyone.
Start with the thermostat. Make sure it's set to "heat" and that the temperature is set above the current room temperature. It sounds obvious, but a power surge can sometimes reset a programmable thermostat to a default mode.
From there, check the circuit breaker — the furnace should have its own dedicated breaker, and a tripped breaker is one of the most common reasons a furnace doesn't come back on after an outage. If the breaker is fine and the thermostat is set correctly, look for the furnace's power switch. It's usually mounted on the wall near the unit and looks like a standard light switch. If it got switched off during the chaos of the outage, flipping it back on is all you need.
Older gas furnaces — and Nassau County has plenty of them, given that the median home here was built in 1955 — may have a standing pilot light rather than electronic ignition. If the pilot went out during the outage, you'll need to relight it manually. The steps are printed on a label inside the furnace panel: turn the gas valve to "off," wait a few minutes for any residual gas to clear, then follow the manufacturer's relighting sequence. It's a straightforward process, and most homeowners can handle it safely.
One critical rule that applies to every furnace type: if there's a reset button on the unit, press it once and only once. Pressing it multiple times is one of the most common mistakes homeowners make, and it can trigger a safety lockout that makes the restart harder — not easier. Press it, give the furnace a few minutes, and see if it fires. If it doesn't, that's the point where you call a technician.
And if you ever smell gas near your furnace — stop immediately. Don't press anything, don't flip any switches. Leave the house, leave the door open behind you, and call your gas provider from outside.
Why Restarting an Oil Furnace After Running Out of Fuel Is Different
Here's where the two systems diverge in a way that catches a lot of Nassau County homeowners off guard. If your oil furnace shut down because the tank ran dry — not because of a power outage — adding more fuel is not enough to get it running again. You have to bleed the system first.
When an oil furnace exhausts its fuel supply, air gets pulled into the fuel lines and the fuel pump. That air creates a blockage that prevents the burner from igniting, even after a fresh delivery. The furnace will attempt to start, fail, and lock out. If you keep pressing the reset button trying to force it, you'll eventually trigger the safety lockout entirely, and at that point you're looking at a service call regardless.
Bleeding the furnace means purging that air from the system. The process involves locating the bleeder valve on the fuel pump — typically a small brass fitting — and cracking it open slightly while the burner is trying to run, allowing the air to escape until fuel flows cleanly. It requires a wrench, a small container to catch the fuel that comes out, and a bit of patience. Some homeowners in Nassau County handle this themselves. Others prefer to have a technician do it, which is a perfectly reasonable call, especially on an older system where the fuel pump or lines may have their own quirks.
What matters most is understanding that this step exists. If you've just gotten a heating oil delivery and your furnace still won't start, you're not dealing with a broken furnace — you're dealing with air in the lines. That's a specific, solvable problem. But it's also the kind of problem that automatic delivery is specifically designed to prevent. When your tank never runs dry in the first place, you never have to bleed the system, and you never have to stand in a cold basement trying to figure out why the furnace won't respond after a fill.
The restart procedure for an oil furnace after a planned outage — say, the power went out and came back, and the tank has plenty of fuel — is much simpler. Check the thermostat, check the breaker, check the power switch, and press the reset button once. In most cases, the furnace will cycle back on without issue.
Restarting a Gas Furnace vs. Oil Furnace: Questions Nassau County Homeowners Ask
The questions below come up constantly among Long Island homeowners — especially those who've recently bought an older home in Nassau County and aren't entirely sure what kind of heating system they inherited. If you've been wondering about any of these, you're not alone.
Is Gas or Oil Heat Better for Nassau County Homes?
The honest answer is that it depends on your home, your situation, and what you value most. Neither fuel type is universally better — they each have real advantages that matter in different ways.
Gas furnaces tend to require less maintenance. There's no soot buildup to clean, no nozzles to replace annually, and the combustion process is generally cleaner. For homeowners who want a lower-touch system, that's a real advantage. Natural gas is also distributed through the utility grid, which means you don't have to monitor a tank or schedule deliveries.
Oil furnaces, on the other hand, deliver more BTUs per unit of fuel than gas furnaces do — meaning a smaller oil unit can heat a larger space effectively. They also carry no risk of carbon monoxide leaks, which is a meaningful safety distinction. And oil furnaces tend to last longer: well-maintained oil systems routinely outlast comparable gas systems by five to ten years, which matters a lot when you're talking about a home that was built in 1955 and has an installed base of equipment that's already proven its durability.
There's also the question of supply control. With oil heat, you choose your supplier, you set your delivery schedule, and you're not tied to a single utility's pricing and infrastructure. That flexibility has real value, particularly in Nassau County where a significant portion of homes — especially the post-war Cape Cods and split-levels that define so many neighborhoods — were built before natural gas lines were widely available, and where conversion to gas involves real upfront costs.
If you're weighing a switch from oil to gas, it's worth knowing that oil-to-gas conversion typically involves gas line installation, new equipment, oil tank removal, and permitting. The upfront cost is substantial, and the payback period depends heavily on how fuel prices move — which is unpredictable. Many Nassau County homeowners who've done the math have decided to stay with oil, particularly when they're working with a reliable supplier and a well-maintained system.
Is Gas or Oil Heat Cheaper in Nassau County, NY?
This is probably the most common question, and it deserves a straight answer rather than a hedge. Natural gas has generally been cheaper per BTU in recent years, and that's worth acknowledging honestly. But the cost comparison is more nuanced than a simple price-per-gallon figure.
Current Long Island heating oil prices average around $4.08 per gallon according to NYSERDA data, with prices projected to average $3.50 per gallon in winter 2025. Those numbers fluctuate with global energy markets, and they can move significantly during peak demand periods — NYSERDA has tracked recent highs reaching $4.94 per gallon. Natural gas prices, regulated by the utility, tend to adjust more gradually, which gives them a stability advantage in some years.
That said, oil furnaces burn fuel more efficiently in terms of heat output per unit, which partially offsets the per-gallon price difference. And the way you buy your oil matters a lot. COD heating oil — where you order as needed with no contract — can save $0.50 to $0.90 per gallon compared to full-service automatic delivery contracts. On a typical 200-gallon delivery, that's $100 to $180 in immediate savings. For Nassau County homeowners who are comfortable monitoring their own tank and ordering when needed, that's real money.
The other cost variable that often gets overlooked is the conversion cost itself. Switching from oil to gas isn't free — gas line installation, new equipment, tank removal, and permits add up quickly. For a home that already has a functioning oil system and a reliable fuel supplier, the economics of staying with oil are often stronger than they appear at first glance, especially when you factor in the longer average lifespan of oil furnaces.
The bottom line: if you're already on oil heat in Nassau County, the cost difference between the two fuels is real but not as dramatic as it's sometimes made out to be — and the flexibility, safety profile, and longevity of oil systems are factors that deserve equal weight in the calculation.
When Your Nassau County Furnace Won't Restart, Here's Where to Start
Gas and oil furnaces share some restart steps — check the thermostat, check the breaker, press the reset button once — but they diverge in one critical way. If your oil furnace ran dry before it shut down, you're dealing with air in the fuel lines, and that requires bleeding the system before it will fire again. Knowing that distinction ahead of time saves you from a frustrating afternoon of pressing the reset button and wondering what's wrong.
The most reliable way to avoid the dry-tank restart scenario entirely is to never run out of oil in the first place. That's what our automatic delivery program is built around — predictive scheduling that gets fuel to your tank before it becomes a problem, without you having to think about it.
If you have questions about your heating system, your fuel options, or how delivery works for Nassau County homes, we at OK Petroleum Distribution have been answering those questions for Long Island homeowners for over 40 years. We're here when you need us.
