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Can I Heat My Workshop With Waste Oil? Yes, If the Heater Matches Your Oil

by | Oct 16, 2026 | Uncategorized

waste oil heater

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Yes, you can heat a workshop with waste oil, as long as you buy a purpose-built heater sized to the oil you really collect and the heat your building really loses. The figure that should drive the purchase is litres of oil per season, not square metres of floor. A heater that out-burns your supply has you buying fuel in July, and one that under-burns it leaves drums stacking up against the back wall.

How a Waste Oil Burner Turns Dirty Oil Into Shop Heat

Used oil straight from a sump or a fryer is a difficult fuel. It thickens in the cold, carries water and fine metal from engines, and in the case of cooking oil, food solids and fats that set at room temperature. A purpose-built heater exists to turn that inconsistent liquid into a steady, clean flame, and it does so with a chain of parts that each solve one problem.

The chain starts at storage, where oil sits long enough for water and heavy sludge to settle to the bottom, away from the draw-off point. From there a feed system delivers oil to the burner at a controlled rate. Before it can burn cleanly, the oil has to be thinned and broken into fine droplets so it mixes with air, because a pool of thick oil smokes and soots instead of combusting.

Combustion happens inside a sealed chamber, and the heat passes through a heat exchanger. That exchanger is the part that matters most for a workshop: it keeps the combustion gases on one side and the air or water you are heating on the other. The gases leave through a flue. In a space heater, a fan pushes shop air across the hot exchanger. In a hydronic system, water passes through the exchanger instead and is pumped out to radiators or floor loops, often split into separate zones.

The consequence for planning is simple and often missed. Because the feed sets the burn rate, a given heater consumes oil at a roughly fixed rate per hour of firing. Multiply that by the hours you expect to run it across winter and you have its seasonal appetite, which you can compare against your own drum log before you spend a dollar.

Why Burning Used Engine Oil Goes Wrong in Improvised Heaters

Improvised burners fail because the fuel changes and nothing in the device responds to it. Engine oil, gearbox oil and hydraulic fluid have different viscosities, and all of them thin out as they warm. A drip-fed pot that runs cleanly at mid-morning will flood or starve by afternoon as the shop warms and the oil flows differently.

Water is the next leak in the design. A drum left outside picks up condensation and rain, and water in the oil makes a flame spit, stall and relight unevenly. Settled storage and a high draw-off handle this in a proper system; a hose dropped into the bottom of a drum feeds the burner the worst of it first.

The deeper problem is that most homemade units have no heat exchanger at all. The flame heats a steel box, and the room air mixes freely with whatever the burner is producing. In a closed workshop full of people, that is the wrong place to be learning how complete your combustion is.

Then there is the paperwork. Burning oil is regulated as waste disposal in parts of Australia, and an appliance you welded yourself gives an insurer or an inspector nothing to assess. A manufactured heater at least gives you a defined appliance to discuss with your state environment authority.

Setting Up Oil Heat in Your Workshop, in Order

  1. Log the oil you generate for a full season before choosing a heater, counting drums or litres per month, and note the dips, such as holiday shutdowns, when collection falls.
  2. Estimate the building's heat loss from its real condition: wall and roof insulation, roller doors that open through the day, ceiling height and draughts around the eaves.
  3. Compare the two figures, and where your oil cannot cover the full heating season, plan for a top-up fuel or a smaller burner rather than a bigger one.
  4. Choose the delivery method: a direct space heater for one open shop, or a hydronic system when the office, amenities and floor need heat on separate schedules.
  5. Contact your state EPA about authorisation for burning oil as fuel at your site, and keep the response with your records.
  6. Set up storage that lets oil settle, keeps rain out and draws from above the sludge layer, with filtration between tank and burner.
  7. Keep vegetable oil from food businesses clear of food solids, and keep solvents, coolant and parts-washer fluid out of every drum, so burning used cooking oil for heat stays as predictable as burning engine oil.
  8. Have the heater and flue installed properly, then record running hours and oil use through the first winter so you can confirm your sizing against reality.

Mistakes That Make Oil Heat Expensive

Sizing from floor area alone is where most budgets go wrong. Two sheds of the same footprint can lose heat at very different rates, and a heater chosen from a square-metre chart may need far more oil than the business produces. Start from your oil log and your heat loss instead, and let the floor area be the last check.

A drum of mystery fluid can undo a good installation. Brake fluid, coolant, thinners and degreasers find their way into waste oil when one drum serves the whole workshop. Give oil its own labelled containers, and tell staff that anything else goes elsewhere.

Treat "free fuel" with care. Oil is the cheapest way to heat a workshop only while you generate it yourself or collect it at no cost; once you start buying oil to keep the burner going, the economics change. That usually signals an oversized heater rather than a fuel problem.

Skipping maintenance costs more than the service would have. Soot on a heat exchanger cuts the heat that reaches the shop, so the burner runs longer for the same comfort and drinks more oil. Book a yearly professional check of the flue and combustion chamber, and clean between visits as the manufacturer directs.

Forgetting the people in the building is a planning error, too. An open-plan air heater suits a single shop floor, but an office or lunchroom that needs steady warmth when the roller doors are open will never be comfortable on the same blast of hot air. Zoned hydronic heat solves that, and it is far easier to design in at the start than to add later.

What the Rules and Numbers Tell You

The hard numbers on oil heating in Australia come from regulators, not from fuel-cost tables, and they should shape your plan before any savings estimate does. Tasmania's EPA lists oil among the prohibited wastes that must not be burned for heating or cooking unless specifically authorised.

The penalty is concrete. In Tasmania, an infringement notice for offences related to wood heater standards and burning prohibited waste carries an on-the-spot fine of 5 penalty units, which the EPA puts at $1,025 in 2025/26. That is a single notice, and it applies whether the oil was burned in a manufactured heater or a cut-down gas bottle, which is exactly why the authorisation step comes before installation.

Other states frame used oil through their own waste rules. In Victoria, EPA Victoria's guidance on this sits within the Industrial Waste Resource Guidelines, which offer guidance for wastes and resources regulated under the Environment Protection framework. Read the guidance that applies to your state and site rather than assuming a neighbour's arrangement covers you.

On whether waste oil heating is cheaper than wood, the honest comparison rests on what you already have. If your workshop produces a steady flow of oil, the fuel side of the ledger is close to nothing. If you have a reliable timber supply and room to store it, wood has a strong efficiency case: our wood gasification hydronic boilers run at 90%+ efficiency, under certification B32 00842 14. Wood must be adequately seasoned to avoid creosote buildup. Pick the fuel your business already generates or can store well, not the one with the better brochure.

How We Size and Supply Oil Heating

Our core business is the heating and burning of waste oil and wood. We supply waste oil heaters for domestic and commercial space heating. Our heaters burn used or unused automotive and vegetable oils. That matters for workshops whose drums hold a mix from the service bays and a nearby food business.

For buildings with more than one heated area, the choice between a direct heater and a waste oil boiler comes down to how the space is used. We also design hydronic heating from recycled waste and used oils. Our hydronic design services cover multiple independent heating zones, so an office, a parts store and a shop floor can each run to their own schedule from one oil supply. We serve domestic, commercial, farming and industrial heating. One visitor put the appeal plainly:

"At the recent 2015 AAAA show at the Melbourne Exhibition Centre, we met with the Kroll team and loved what the guys had to say about domestic heating and workshop space heating from old dirty waste oils. Thanks again." (George Taylor)

If your oil output is small or irregular, oil may not be your best fuel, and we will say so. In our wood gasification system, the boiler charges a 330 litre accumulating water tank, originally via a Laddomat circulator and valve, now replaced by an LK 810 charging valve that protects the boiler from condensation and manages hot water accumulation. Those boilers need regular cleaning to remove ash and annual professional checks. Our wood pellet hydronic boilers are available in 2026 for sites that prefer a more uniform fuel than split timber. Whatever the fuel, we advise professional annual checks for the chimney and combustion chamber.

Bring us your oil log and a description of the building, and we will help you match a heater to both. You can reach us at sales@krollheat.com, on 1800 805 243, or at Factory 6, 4 Kirkham Rd, Dandenong Victoria 3175.

Frequently Asked Questions

How much waste oil do I need to heat a workshop?

It depends on the heater's burn rate and how many hours you run it, so the useful question runs the other way: how much oil do you produce? Log your drums or litres per month across a full season, including slow periods. Then choose a heater whose hourly consumption, multiplied by your expected winter running hours, fits inside that figure. If your supply falls short, a smaller burner or a top-up fuel is a better answer than an oversized heater that runs dry partway through winter.

Can I burn used cooking oil and engine oil in the same heater?

A heater built for both can handle a mixed supply, and our heaters burn used or unused automotive and vegetable oils. The work is in preparation. Cooking oil from food businesses should be free of food solids, and every drum should be kept clear of solvents, coolant, brake fluid and degreasers. Let the oil settle so water and sludge stay below the draw-off point, and filter it before it reaches the burner. Consistent fuel gives a consistent flame.

Rules differ by state, so check with your state EPA before installing anything. Tasmania's EPA lists oil as a prohibited waste for heating or cooking unless specifically authorised, and burning prohibited waste can bring an on-the-spot fine. In Victoria, used oil sits within EPA Victoria's Industrial Waste Resource Guidelines. Get your site's position in writing, keep it on file, and treat that step as part of the installation, done before the heater arrives rather than after.

Should I choose a waste oil space heater or a hydronic boiler?

A direct space heater suits one open shop where the goal is warm air across the floor. A hydronic system suits buildings with several areas that need heat at different times, such as an office, amenities and the workshop itself, because it can run multiple independent zones from one heat source. If staff complain that the office is cold whenever the roller doors open, that is the case for hydronic design.

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