I have a Weil-McLain oil furnace that provides heat (hot water through radiators) and hot water. I do not have a separate hot water tank (there is a small tank on top of it), nor do I really have the room for one. When using one device (say a sink) the volume of hot water is sufficent, however when another device is turned on there is a drop in the hot water volume.
The tempurature is fine, but because of the defficency in volume you cannot say take a shower and run the washing machine at the same time.
The boiler is about 20 years old or so and I had one of those "sonic" cleanings done (which helped a bit) but eventually I want to install a new shower down stairs and would like to be able to have both of them running at the same time.
I had considered upgrading to gas but in order to bring the line to my house would have cost me $31,000 out of pocket so that's not an option. My only other options are to get a new oil furnace or perhaps look at propane.
I just wanted to get some thoughts on what I could do to get sufficent hot water to multiple devices at the same time. I was told by my oil service company that my burner is at about 80% efficency.