Tankless Water Heaters - Efficiency vs Economy

Well it does in an manner of speaking. But it’s not just the amount of oil you are burning that the savings come from, but also the residual heat left over from the on cycle. Any left over BTUs from your steam making (on) cycle will continue to be used to heat the water in your tankless coil.

I’m just thinking that the larger flue on a gas burning boiler will suck more heat during the off cycle that the smaller flues found on oil burners. If you had an installer who was smart enough to install a vent damper then you would gain even more savings. The more heat you keep in the boiler, the more money you save 😉

-SteamMan

I appreciate this thread a lot. Thanks to everyone who is contributing.

We have CosmoGas tankless heaters (Italian) in my building. There are 13 units here and some units break down all the time while others never fail. When the units are reliable, they are fantastic for hot water. We didn’t factor in the installation cost because the building installed them and the cost ended up in the unit purchase.

I’m very happy with mine and it saves a lot of space in a small condo.

Does anyone know of a plumber who has worked on CosmoGas units? If not, does anyone know if a plumber who specializes in tankless units? If so, we have work for them.

Interesting comments from some folks here. The two most interesting being rowhouse and mopar.

Re rowhouse: The stats show that most people do as you plan. That is, wait until the tank goes and then get a new system. Unfortunately for them it often plays out badly. Most people want to upgrade and get a more efficient system however they wind up installing the same thing they had because of the pressure of not having hot water. It pays to do your homework beforehand so you are prepared to direct your plumber as to your desired system. In that manner he/she will be able to get you back up and running quickly with a newer, more efficient system.

Re mopar: I am surprised to hear that your tankless coil is as economical as you say. I install tankless coils frequently. Usually in commercial settings and sometimes in multifamily dwellings. They work great in the winter especially when properly set up with low flow fixtures and a flow limiter. However in summer they aren’t efficient at all unless you can put your burner in low fire hold, which most homeowners don’t have the option of.

I have something in my archives written by a friend, discussing the whole concept of tankless coils and conventional hot water heaters working together. I would have to go searching for it. Is anybody interested?

-SteamMan

Master Plumber, I am including the non-heating months. I added up all the bills for the year and divided by 12, and it works out to $155 a month.

At the apartment where we used to live, the bills were $60 in the summer but $200 to $300 in the winter.

Ah, they included cooking gas. Hm.

In any case, my recollection is that it averaged out to about $180 or so — roughly the same.

We have no insulation, and the windows don’t work at all, but we’re heating three times the space for about the same, so I am pleasantly surprised.