Heatable Heating Oil Glossary & Terminology

Heatable Heating Oil Glossary and Terminology
If you thought it was hard to keep up with the acronyms on a Reddit thread, try working in the heating oil industry. Sometimes it feels like we’re swimming in alphabet soup. To make things easier, we’re outlining all the terms you’re likely to see in the heating oil space – and we’ll continue to add more as you find ‘em! 

275 – The size (in gallons) of the average oil tank.  Although we can only put 240 gallons of heating oil in at a time, it’s nice to know you have the capacity. Best way to keep it full is to remember to “order at a quarter”.



Absorbent Pads – specially-designed pads that will absorb oil in the case of a spill

Additives –used to improve combustion, reduce waste, and dissolve sludge and inhibit rust in the heating system. These are the good kind of additives.

AFUE – stands for Annual Fuel Utilization Efficiency.  It’s used to measure how efficiently your furnace burns heating oil. The more efficient your furnace, the more heat you’ll get per gallon of heating oil.

ATU – stands for Annual Tune Up. Each year, you should have your heating system cleaned and inspected. While here at Heatable we don’t provide service (just heating oil), Google recommends plenty of people who can.

Authorization Hold – used to ‘reserve’ money in your account without taking it out. Heatable uses authorization holds to signal your bank or credit card to hold the amount of the charge, but your money isn’t released until your oil is safe and sound in your tank.


Barrel – this is how heating oil is measured. A barrel contains 42 gallons.

Biodiesel – oil most often made from soy, palm, canola, or other refined vegetable oil. It can be blended with any type of heating oil.

Biofuel – biomass that has been converted into a fuel 

Bioheat– a blend of heating oil and biodiesel

Biomass – organic matter used as a fuel 

Blend – a mixture of heating oil and diesel 

Blizzard – a wicked big snowstorm with high winds and low visibility. In the South, any form of white precipitation.

Bulk plants – Used for the temporary storage of heating oil and other fuels by heating oil delivery companies. Usually consist of above-ground storage tanks.

Burner (within the furnace) – the section of the furnace where heating oil vapor is burned.

BTU – an acronym for British Thermal Unit. Not to get all scientific on you, but it’s the traditional unit of heat, defined as the amount of heat required to raise a pound of water by one-degree Fahrenheit.


Cap (Fill Pipe) – like a little hat that sits on the fill pipe, keeping your oil fill pipe nice and clean.

Celsius – you know this. It’s a temperature scale where water freezes at 0 degrees and boils at 100. Fun fact: the Fahrenheit and Celsius scales coincide at -40 degrees. It’s like saying it’s terrifyingly cold in two languages. 

Corrosion – a chemical reaction where metal reacts with moisture and oxygen to form metallic oxides. You know it as metal getting that ‘I’m being eaten away’ look.

CDL B – an acronym for Commercial Driver’s License.  Fun fact: B is the level needed to drive a heating oil truck.


Delivery – when your heating oil arrives at your home.

Delivery Driver – the kind person driving the big “rorange” Heatable oil truck. 

Delivery Slip – what your Heatable driver leaves at your house after a delivery, letting you know how much heating oil was delivered.

Delivery Tag – a plastic “bracelet” we put on your fill pipe that has a number on it and lets the driver know that he/she is at the correct house and that it’s safe to fill.

Degree Days – it’s a way of saying how warm or cool the weather is on any given day by seeing how many degrees the weather differs from 65 degrees. It just helps full-service companies figure out when to automatically fill your tank.

Distillate Fuel – a general classification of fuel. A distillate is a product of the distillation process at an oil refinery.


Emergency shut off – that switch on your burner or boiler that looks like a red light switch. Turns your heating system off in an emergency. 


Fahrenheit – temperature scale based on one created by Gabriel Fahrenheit in 1724.

Flash Point – the temperature at which heating oil (or any compound) gives off sufficient vapor to ignite in air. Do not try this at home.

Fill pipe – the pipe that brings your heating oil from the Heatable truck to your oil tank. #VIP

Float – not to be confused with a parade float, the float inside your oil tank moves up and down with the level of oil. It connects to the fuel gauge and helps show how much oil you have left.

Fuel Oil – any oil used as fuel in an engine or furnace

Fuel #1 – similar to kerosene

Fuel #2 – a distillate home heating oil

Fuel #3 – good for burners that need low-viscosity fuel

Fuel filter – connected to your oil tank and the fuel line to your furnace and used to keep things nice and clean and clog-free.

Furnace – where all the action happens, and hot air is heated before it goes out to heat your home 

Fuel Temperature Correction – basically something used to try to tame down the havoc wreaked by temperature. Because colder temperatures make fuel contract, oil companies in New England provide oil based on the gross amount delivered to your tank.


Gallon – the measurement used to deliver heating oil. 

Gel Point (also known as Wax Point) – temperature at which heating oil freezes solid and can no longer flow through fuel lines. AKA v cold.


HazMat—in addition to a CDL B license, heating oil delivery drivers need to pass a test that certifies that they can deliver heating oil (and other materials that are deemed hazardous by the government).

HVAC – an acronym for Heating, Ventilation, and Air Conditioning… the different systems used to move air. 

HAVCR – an acronym for Heating, Ventilation, Air Conditioning, and Refrigeration.

Heatwave – a prolonged period of abnormally hot weather.

Hose (i.e. on the heating oil truck) – heating oil flows through a hose to move from the oil truck to your fill pipe.


K-Factor – commonly used by full-service companies to explain consumption. The k-factor is a calculation that shows how quickly a home is consuming fuel and represents the number of gallons of oil (fuel) burned per degree day. 

Kerosene – a combustible hydrocarbon liquid derived from petroleum during the refining process. Used in outside heating tanks because it doesn’t gel in cold temperatures and in specific heating systems (e.g. monitor heaters).


LP – an acronym for Liquid Petroleum Gas, a flammable hydrocarbon gas liquefied through pressurization.


Meter – located on Heatable’s big rorange oil trucks (and all oil trucks). It’s registered with the U.S. Weights and Measures Division and accurately measures how much oil goes through the hose and is delivered to your house.


Natural Gas – a flammable gas made up of mostly methane and other hydrocarbons occurring naturally underground.

Nor’easter – a storm of very heavy rain or snow most intense during a New England winter (of course). It gets its name because its winds typically come out of the Northeast.

Nozzle – located inside the furnace, the nozzle is what turns heating oil into a fine mist when the oil is squirted through it.

Number Two/# 2 – this is what Heatable and all other heating oil companies deliver. Heating oil in the U.S. is known as No. 2 heating oil.


Off-road diesel – used to power equipment and vehicles that don’t go on roads. It’s dyed red and illegal to use in an on-road vehicle.


Oil line – Carries heating oil from the oil tank to the burner.

Oil truck—our big rorange trucks that bring the heat to your home. 

On-road diesel – used to power vehicles that go on roads.

Outside tank – an oil storage tank that lives outside your home. Outside oil tanks should be filled with Kerosene of some type of heating oil and diesel blend.


Pre-Buy – used by full-service companies as a way to lock in a lower price for heating oil. Customers pay a fixed price for oil up front (usually during summer).

Polar Vortex – a nightmare cold from Canada.

Prime & Start – Yeah, you’re gonna want to avoid having to do this. It’s a way to restart your furnace after you’ve run out of oil. It also means your S.O. is no doubt giving you grief for running out in the first place.


Refinery – where heating oil is born from crude oil.

Red Dye – used to change the color of heating oil so it won’t be taxed. Kind of cool. 


Solvent – dissolves oil


Tank – The big container that holds your heating oil

Tank gauge – Usually located on the top of your tank, it tells you how much oil you have. Very important to make it your friend.

Tanker – size large ship that transports bulk oil

Tanker truck – carries heating oil to and fro

Tank Inspection – Should be performed periodically to make sure everything looks ship shape. Do this especially if you are buying a new house. If you have any questions or are unsure, you can request a free inspection from Heatable.

Temperature (temp) depressant – allows oil to be used at lower temperatures

Thermostat – the start of the heating magic in your home, it signals your heating system to either turn up for more heat and down for less.


ULSHO – an acronym for Ultra Low Sulfur Heating Oil. As Martha Stewart would say, “It’s a good thing.” 

ULSD – an acronym for Ultra Low Sulfur Diesel. Also, a “good thing”. 

Ultra-low sulfur heating oil – heating oil with a sulfur content of 15ppm vs traditional heating oil’s 4,000 ppm.


Vent pipe – leads from the inside of your home to the outside of your home to relieve the vacuum created when your burner pulls oil from the tank. It’s a good idea to clear the snow from this (as well as from your fill pipe) during winter.

Viscosity – basically, how thick and sticky a liquid is. The higher the viscosity, the higher ‘ewww’ factor. 

Volatility – how unpredictable something is.


Whistle – helps your Heatable driver know when you tank is full. Usually found in the vent pipe, it blows as heating oil is pumped into the tank and stops when the tank is full. Like magic—but not.

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