Can my landlord make me fill oil tank?

What does your lease say?
If your rental agreement says you have to use oil heat, Yes.
If your landlord is paying for electricity or other utilities, I think I know why he wants you to fill the tank and use oil heat.

Welcome to Fluther.

Does the lease say you are responsible for heat and the landlord pays electricity?
Where do you live and how big is the house or apartment? . Here in Western NY (typical winter of 6400 HDD, Heating Degree Days) a well insulated 2000 sq ft house heated to 65 F, can expect to use 750–1000 gallons of heating oil at $3.50 per gallon. So heating costs can be anywhere from $2100 to $3500 per year. A smaller place in a warmer climate will have heating costs much lower.
On a per BTU level, electric heat is about the same cost. If you have heating costs on this order, I can assure the landlord will adjust the lease or rent as soon as he can.

Maybe he considers the electric heaters a fire risk.

Welcome to Fluther.

I’m assuming that electricity is included in the rental, and oil for the furnace is not. Therefore, it’s clear that you would be “expected” to use the oil heat, but it depends on the language of the lease whether that can be enforced / required or not. (If the place has hot water produced by the oil furnace, which is typical for an oil-heated house, then you’ll eventually want to use the furnace for that, anyway.)

Oil heat is definitely cheaper than electric, but perhaps not “to you”, based on your current agreement. Also, if the furnace is not used and you get very cold weather that freezes the pipes – including the heating water pipes (assuming a hot-water baseboard heating system) then you risk the entire structure in case the system freezes. (This could also happen if you go away for a weekend, for example, and simply turn off the space heaters since you won’t need them.)

Let’s say that you eventually use the oil heat.

In that case, insist that the landlord fill the tank initially, and you can be responsible for either leaving the house with a full tank again or paying him the estimated difference between a partially-full tank and what it will cost to fill. Otherwise, you’d be leaving him money in the tank that you probably won’t get back. (This is analogous to a rental car scenario. You rent the car with a full tank of gas and return it the same way, or pay the difference on the fuel gauge.)

Not using the oil heat can cause the furnace to deteriorate to the point where it will have to be replaced.

I like @CWOTUS idea of asking him to fill it the first time and you will make sure it is full when you leave.

We own a rental house that uses oil heat (as does our own residence). While we don’t require that the tenant use oil heat, we do inform all prospective tenants that electric space heaters won’t do the job when it gets very cold, that pipes will freeze, and that they will be responsible for it if that happens. Our tenant pays all utilities, so it doesn’t have anything to do with saving us money on electricity…it’s all about making sure the house is maintained at a warm enough level to protect it.

We let them know upfront that oil heat is expensive (because you have to order and pay for a minimum amount of oil all at once (here, it’s 100 gallons). We tend to price our rent a bit lower because of it.