Oil - no, Diesel - yes. Furnace question

Thanks to a misinterpretation of our oil gauge, we ran out of oil (nearly we think. It was still running when we turned the heat down so we don’t think it’s completely empty). We have been trying to get oil delivered since Monday but the crappy weather and a whole lot of emergency calls from people with small children, old people, and no backup heat source, have caused us to be pushed to the bottom of the list.

Our oil lady said that we can substitute diesel. We weren’t thrilled with the idea so we’ve been avoiding it all week. But, they still haven’t been able to get to us. We’ve had the heat set to 50° all week and we have had a raging fire going for about 100 straight hours. The fire has kept the house at a balmy 53°, which has kept the heat from cycling. But, we’re almost out of firewood now so we had to go with the diesel.

So, how long can we use diesel in our oil tank? Also, how long can we expect 10 gallons to last? Is this just a Band-Aid on a gaping, oozing wound? Should we just let the house warm up and then turn it back down again?

No. 2 fuel oil (heating oil) and diesel fuel are essentially the same thing. 10 gallons of diesel should last you as long as 10 gallons of heating oil would.

Ok, that’s good to know. Thank you. I have no clue how long 10 gallons of oil would last us. Honestly, I’m not even certain the gauge was really on empty. Everyone said to go based on the bottom of the yellow plastic thing but even after we get a full delivery, the bottom hovers around 3/4 of a tank. So, either they’re not filling it or we’re supposed to go by the top of the plastic thing. We don’t know for sure.

I really miss gas heat. Getting periodic deliveries sucks.

wear long johns and sweaters.

diesel is cleaner and close enough to use.

HA! You should see how I’ve been dressing this week. Blankets upon layers upon layers. Our primary concern with running out of wood AND oil is having the temp drop enough for the pipes to freeze. For now we’ve managed to keep everything warm enough but if we run out of both and can’t get a delivery of either, our pipes are screwed without the diesel. I can’t even get a return call from our wood guy. I’d rather not go with someone else. Last time we did, we got shit wood.

I’m glad that we put the water on an electric heater and I’m annoyed that we did. If our water was still on the oil line, we would have gotten oil on Monday. But, they know our water is separate and we have a huge fireplace. It’s a good thing I’m home all day to keep it going.

I’ve used diesel in my furnace quite a bit. Never had any problems. Supposedly it’s filtered a bit more than heating oil so it’s actually better. Of course, it’s much more expensive because of this and the extra taxes.

How about kerosene? In 1989, I got to spend three days in a house without heat in northern Virginia (shortage of fuel oil), but somebody said, “Kerosene will do in a pinch”. 20 gallons later, we had heat and my first hot shower in three days.

As cstamets said, no. 2 heating oil and diesel fuel are essentially the same thing. A red dye is added to heating oil so that they can tell if truckers put it in their trucks to avoid the extra taxes on diesel fuel.

In the winter, most filling stations (at least where it’s cold) switch to a winter blend of diesel fuel, which is basically no. 2 heating oil mixed with a bit of no. 1 fuel oil (kerosene) to stop it from gelling or waxing as easily in the cold. This same mixture is also sold as winter blend home heating oil. This is sold in colder climates to folks with outdoor oil tanks. Again, the home heating version has a red dye added to it to prevent truckers from using it.

If you use diesel fuel in your home heating system you are paying unnecessary highway taxes on the fuel, but it won’t cause you any harm. It’s a waste of money to do it regularly, but in a pinch it works just fine.

I have fuel oil for heat, and I’m never sure if it is the bottom of the yellow gauge or the top I should be looking at. Maybe it’s the middle.

As far as diesel:fuel oil, the SDMB poster you need to solicit is Una Persson, our resident fuel expert.

Kerosene will work, but won’t work as efficiently. It costs more and doesn’t have as many BTUs per gallon. You wouldn’t want to use it all the time because of that, but if there’s an oil shortage and you are in danger of running out of heat it will certainly do the job.

I heat with # 2 fuel oil and regularly use that fuel in my diesel generator. Other than the red dye, it’s the same.

At truck stops around here, you can buy “off road diesel” which is the dyed stuff, meant for generators and bobcats, etc, and save the highway taxes.

As to how long it lasts, the oil nozzle in the furnace will have a GPH rating - how many gallons they burn per hour of operation. I think .75 or .8 GPH is typical for a home installation - you can ask your oil guy what you have at the next tune up.

The two (diesel and #2 oil) are not exactly the same, but in a pinch you can often use one for the other. In the world I work in, where the wrong fuel oil could wreck a $10,000,000+ GT, you always want to check to make sure there isn’t some additive or issue with the burner design/fuel oil viscosity.

It can be useful to cross-check the gauge indication by using a dipstick - typically something like a yardstick.

Just to emphasize that will give you the max possible amount of fuel you will burn in a day (1 gal/hour * 24 hours = 24 gal), though normally the furnace will cycle on and off.