At least here in most of the USA they are usually very similar, and in much of the Northeast they now must both be below 15PPM sulfur, so they would be interchangeable. From Wikipedia:
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In many markets heating oil and on-road diesel fuels are the same product sold out of the same truck in route labeled as either heating oil or dyed diesel respectively dependent on the person ordering product.
As I've said, many times I've seen large yachts and fishing boats fill up from a home heating oil delivery truck. I've asked a few times and they told me it was just home heating oil.
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In many markets heating oil and on-road diesel fuels are the same product sold out of the same truck in route labeled as either heating oil or dyed diesel respectively dependent on the person ordering product.
As I've said, many times I've seen large yachts and fishing boats fill up from a home heating oil delivery truck. I've asked a few times and they told me it was just home heating oil.