Oil Boiler FAQs

Answers to the questions Maine and New Hampshire homeowners most often ask us about oil-fired boilers — how they compare to gas, which brands we work with, and what to expect from a modern high-efficiency oil system. Have a question that isn’t covered here? Contact us and we’ll get you a straight answer.

Oil Heat Basics for Maine and New Hampshire Homes

What is an oil-fired boiler, and how is it different from a gas boiler?

An oil-fired boiler heats water for your hydronic distribution system (baseboards, radiators, or radiant floors) by burning #2 heating oil in a combustion chamber instead of natural gas or propane. The oil is stored in an on-site tank and delivered by a local supplier, which gives homeowners more control over fuel pricing and delivery timing than a utility-metered gas connection. Mechanically, oil boilers use the same cast-iron or steel heat exchangers, circulators, and controls found in gas systems — the main difference is the burner and fuel-handling equipment.

Is oil heat still a good option for homes in Maine and New Hampshire?

Yes. Oil heat remains one of the most common home heating fuels across both states, and modern oil boilers are dramatically more efficient than the equipment they typically replace. Many rural properties in our service area also don’t have access to a natural gas line, which makes oil (or propane) the practical choice for a hydronic system. We size and install oil boilers using the same accurate Manual J load calculations we use for gas systems, so the equipment is matched to your home rather than oversized.

How efficient are modern oil boilers compared to older models?

Most of today’s oil boilers deliver AFUE efficiency in the mid-to-upper 80% range, and some high-efficiency models push into the high 80s when their real-world seasonal performance is measured. That’s a significant jump from oil boilers installed 20 to 30 years ago, many of which operated well below 70% efficiency. Replacing an old, oversized oil boiler with a properly sized modern unit is often one of the fastest ways to cut a home’s heating fuel consumption.

What should I know about my oil tank and fuel delivery?

Oil tanks (indoor or outdoor, steel or double-wall poly) should be inspected periodically for corrosion, leaks, and secure venting, and most suppliers offer automatic delivery so you’re not tracking fuel levels yourself. If you’re replacing an aging boiler, it’s also a good time to have your tank and oil lines evaluated, since a corroded line or failing tank can cause problems long before the boiler itself does.

Oil Boiler Brands We Install and Service

In addition to the boiler brands covered on our main FAQ page, we regularly work with equipment from the following oil boiler manufacturers:

What is a Slant/Fin oil boiler, and what makes it different?

Slant/Fin Intrepid (TR Series) is Slant/Fin’s cast-iron oil boiler line, rated up to 86% AFUE. It uses a wet-base cast-iron heat exchanger with thermal pins and a computer-designed combustion chamber, with a swing-open service door and hinged flue collector for easier cleaning and maintenance. Hot-water models carry a lifetime limited warranty; steam models carry a 10-year limited warranty.

What is a Buderus oil boiler, and what makes it different?

Buderus G115WS is a cast-iron oil boiler rated at 86.5–87% AFUE depending on model and venting configuration. It uses Buderus’s patented GL-180M flexible cast-iron sections, designed to resist thermal shock, along with a three-pass combustion chamber and an integrated Beckett AquaSmart burner with outdoor reset capability. The heat exchanger is covered by Buderus’s residential warranty, with full coverage in year one and prorated coverage continuing through 25-plus years.

What is a Saint Roch oil boiler, and what makes it different?

Saint Roch SR Universal is a multi-fuel cast-iron boiler from Saint Roch (Verona, Italy), engineered to run on #2 oil, B20 biodiesel blend, natural gas, or propane — it can even be converted between oil and gas by changing the burner. The triple-pass, low-water-content design delivers thermal efficiency exceeding 87%, and it’s built to ASME Class 30 standards with an electronic Fuel Smart 3250TC controller and outdoor reset. It carries a limited lifetime warranty.

What is a Weil-McLain oil boiler, and what makes it different?

Weil-McLain WGO Series 4 is a cast-iron oil boiler rated at 86.0–86.4% AFUE on standard models, up to 87% AFUE on ENERGY STAR–qualified “RD” variants. It features a quick-open top and swing-away burner door for full combustion-chamber access, and select models are certified for B100 biodiesel blends. The heat exchanger carries a 20-year warranty — free boiler replacement in years one through five, then a free heat exchanger replacement through year twenty.

What is the Energy Kinetics System 2000, and what makes it different?

Energy Kinetics System 2000, now sold as System 2000 Frontier® (models EK1F, EK2F, and EK3F), uses a Sealix®-coated plate heat exchanger designed to resist scale buildup, paired with Energy Kinetics’ Energy Manager electronic control to deliver both space heating and near-instant domestic hot water from one boiler. The EK1F model is ENERGY STAR certified at 88% AFUE, and Energy Kinetics’ real differentiator is real-world seasonal performance — the company cites System 2000 cutting fuel bills by around 43% versus a typical 83.5% AFUE tankless-coil boiler. It supports up to 5 heating zones (expandable to 15), is convertible to natural gas, propane, or Bioheat, and is among the quietest oil boilers on the market. The pressure vessel and heat exchanger carry a lifetime limited warranty, transferable to future owners.

What is a New Yorker oil boiler, and what makes it different?

New Yorker CL Water Series is a cast-iron, wet-base oil boiler rated up to 87% AFUE. It includes an integrated electronic control with a thermal-purge function that recirculates warm boiler water before firing to cut standby losses, along with a swing-away cast-iron burner door for easy combustion-chamber access. An optional tankless coil is available for domestic hot water, and the boiler carries a lifetime limited warranty.

What is a Burnham oil boiler, and what makes it different?

Burnham MPO-IQ is a cast-iron, 3-pass sectional oil boiler rated at 87% AFUE and ENERGY STAR qualified. Its Burnham IQ control system includes built-in return-water-temperature protection, and a reversible swing door eliminates the need for a target wall or blanket during service. The cast-iron heat exchanger carries a limited lifetime warranty, plus a 1-year parts and labor warranty.

What is a Viessmann oil boiler, and what makes it different?

Viessmann Vitorond 100 (VR1) is a cast-iron, triple-pass oil boiler rated up to 87.1% AFUE, with a stainless steel combustion chamber insert and 3½-inch thermal insulation to reduce standby losses. Smaller models offer a direct-vent option, and an optional Vitotronic outdoor-reset control can be added for tighter efficiency. It carries a 20-year limited warranty for residential installations.

What is a PurePro oil boiler, and what makes it different?

PurePro Advantage is a cast-iron, wet-base oil boiler rated at 87% AFUE and ENERGY STAR rated at most firing rates. It uses a Hydrolevel HydroStat 3250 combination control with fuel-conserving “Thermal Targeting,” and an optional front-mounted tankless coil is available for domestic hot water. It’s built to ASME Boiler Code Section IV and carries a limited lifetime warranty on the cast-iron heat exchanger, plus a 1-year full parts warranty.

Does Local Energy service Laars oil boilers?

Laars no longer manufactures oil-fired boilers — today their lineup is entirely gas-fired boilers and water heaters. Historically, Laars did make oil-fired equipment under the Max and D-Max low-mass boiler line, and if your home still has one of these older units, our technicians can service it. For a new installation, we’d recommend one of the current oil boiler brands above instead.

Ready to Schedule Your Oil Boiler Service or Replacement?

How do I request a free on-site estimate for my oil boiler?

Fill out our online contact form with your name, phone number, and email; your property’s street address (check our Service Areas page first to confirm we serve your town); your current boiler brand and age if known; and your preferred scheduling window. Our office team will reach out within 24 business hours to finalize your appointment.