Oil-to-Gas Conversion in New Hampshire, New Jersey & Southern Maine

What a conversion actually replaces

Changing fuels is not one job. It is five jobs that have to land in the right order, and skipping any of them stalls the inspection.

• A boiler or furnace sized to the house, not to the oil unit you are removing
• A venting path to suit it, which for condensing gear means PVC through a sidewall instead of the chimney
• Gas pipe sized for every appliance you burn now plus the range, dryer or generator you may add later
• A utility service line and a meter set outside
• Retirement of the oil tank, the fill and vent pipes, and the fuel lines

The appliance is the part homeowners picture. Baseboard or radiators means a boiler. Ductwork means a furnace, and that furnace can share a cabinet and coil with central air later. Hot water usually comes along for the ride, either as an indirect tank off the new boiler or a standalone gas water heater.

First question: is there a main on your street

A lot of these conversations end right here, and we would rather end them on day one than after a design. Natural gas reaches only a fraction of New Hampshire communities, mostly the Merrimack valley corridor and the Seacoast. Southern Maine has pockets of service and long stretches with none. Northern New Jersey has whole townships still on delivered fuel while the Shore is largely piped. If no main runs past your property line, the utility prices an extension by the foot, and past a certain distance no fuel savings ever catch up.

When gas is genuinely not available, the real options are propane or a cold-climate heat pump. Propane runs the same condensing equipment with a different gas train and orifice, so you keep the efficiency and the sidewall venting and trade a basement oil tank for a leased or buried propane tank. Per unit of heat it usually costs more than oil, so people choose it for the equipment, not the bill. A cold-climate heat pump makes heat through the coldest nights we get, but it wants panel capacity and a plan for December ice-storm outages, which is why we often leave the existing boiler in place as backup rather than going all-electric.

What conversion week looks like

We start with a load calculation, not a nameplate reading. Oil boilers installed decades ago were routinely two or three times larger than the house needs, and copying that number forward buys short cycling, uneven rooms and a shorter equipment life. We measure the envelope, the windows and the emitters, then size to that.

Permits get pulled before anything is cut. The new appliance and venting go in first so you are not without heat overnight, then the gas piping is run and pressure tested, then the utility sets the meter. Oil lines get capped, the tank gets pumped, purged and removed, and the old flue connection is sealed. We commission with a combustion analyzer, adjust to the manufacturer numbers, and walk you through the shutoffs before we leave.

The chimney problem nobody warns you about

Pull an oil boiler off a masonry chimney and vent the new one out the wall, and you may have just orphaned your water heater. That chimney was sized for the exhaust of both appliances. Left with only a small gas water heater on it, the flue is now far too large, so the exhaust cools before it climbs and condenses inside the masonry. That means acidic moisture chewing the mortar and, in a bad case, combustion gases spilling back into the basement.

The fix is a properly sized liner, or converting the water heater at the same time to a power-vented or sidewall-vented unit. It is a real line item and it is the one most commonly left off a cheap quote.

What drives the cost and the timing

Distance from the main, the length of the interior gas run, whether the tank sits in the basement or buried in the yard, chimney condition, and how many appliances you convert at once. Buried tanks carry the most variability, because closure can turn up contaminated soil and that is its own regulated job.

Local conditions move the number too. Older housing stock across the region often has undersized panels that need attention before new controls and a condensate pump go in. On the Jersey Shore, salt air eats vent terminations and outdoor meters faster, so we pick materials and clearances accordingly. In flood-prone coastal areas we set equipment and gas controls above the flood elevation, because a submerged gas valve is not a repair item, it is a replacement.

Why homeowners hand this one to us

A conversion touches heating, gas piping, venting, water heating and often electrical. Most homeowners end up coordinating two or three trades and a utility. High Ground is licensed in all three, so the crew that sizes the boiler runs the gas and lands the wiring, and one company owns the result.

We are veteran owned, we pull the permits, we price the job before we start it, and every conversion carries our Lifetime Workmanship Guarantee. If something we installed is not right, we come back and make it right. You also get the answer you may not want: if gas will not pay off at your address, we will say so instead of selling you a conversion.

Related Heating & Cooling services

• AC Repair
• AC Install
• Furnace Repair
• Furnace Install
• Heat Pumps