tankless boiler efficiency?

Posted by on July 28, 2006, 4:17 pm

I have hydronic heat in my house and use a oil fired Weil-McClain
tankless boiler that is about 6 years old (WGO Gold or WGTO Gold I
think). It has one output for the hydronic heat and another for the
house hot water...so I don't have a hot water heater. The whole thing
works fine.

My question is whether this is an efficient setup as far as oil usage
goes. The boiler runs year round cause of the house hot water. I know
the heat circuits aren't being used, but it does heat both at the same
time.

I have been considering getting a Boderus direct vent boiler cause I
hate the power vent I have right now and hear Boderus are great
boilers. Would my oil usage be less with a combo boiler/oil hot water
heater year round? I have also heard about indirect fired water
heaters (superstore?). Any experience and suggestions would be
welcomed. I figure I could sell my Weil-McClain cause it isn't that old
and still get a decent $ for it.

Posted by daytona on July 28, 2006, 9:04 pm

Electric hot water tank with timer (Gray Box)

>I have hydronic heat in my house and use a oil fired Weil-McClain
> tankless boiler that is about 6 years old (WGO Gold or WGTO Gold I
> think). It has one output for the hydronic heat and another for the
> house hot water...so I don't have a hot water heater. The whole thing
> works fine.
> My question is whether this is an efficient setup as far as oil usage
> goes. The boiler runs year round cause of the house hot water. I know
> the heat circuits aren't being used, but it does heat both at the same
> time.
> I have been considering getting a Boderus direct vent boiler cause I
> hate the power vent I have right now and hear Boderus are great
> boilers. Would my oil usage be less with a combo boiler/oil hot water
> heater year round? I have also heard about indirect fired water
> heaters (superstore?). Any experience and suggestions would be
> welcomed. I figure I could sell my Weil-McClain cause it isn't that old
> and still get a decent $ for it.
>

Posted by on July 29, 2006, 10:03 am

uh, what would the benefit of an electric hot water tank be in this
scenario?
daytona wrote:

> Electric hot water tank with timer (Gray Box)

> >I have hydronic heat in my house and use a oil fired Weil-McClain
> > tankless boiler that is about 6 years old (WGO Gold or WGTO Gold I
> > think). It has one output for the hydronic heat and another for the
> > house hot water...so I don't have a hot water heater. The whole thing
> > works fine.
> > My question is whether this is an efficient setup as far as oil usage
> > goes. The boiler runs year round cause of the house hot water. I know
> > the heat circuits aren't being used, but it does heat both at the same
> > time.
> > I have been considering getting a Boderus direct vent boiler cause I
> > hate the power vent I have right now and hear Boderus are great
> > boilers. Would my oil usage be less with a combo boiler/oil hot water
> > heater year round? I have also heard about indirect fired water
> > heaters (superstore?). Any experience and suggestions would be
> > welcomed. I figure I could sell my Weil-McClain cause it isn't that old
> > and still get a decent $ for it.

Posted by oløenneker on July 29, 2006, 7:34 pm

beerguzzler50@yahoo.com wrote:
Because an electric water heater will in most cases use less energy than
your boiler, which is designed to heat the entire home rather than a 40
gallon tank of water.
Even a stand alone Gas water heater would bee good as well.
The old tankless systems for a boiler are old tech. and waste energy.

> uh, what would the benefit of an electric hot water tank be in this
> scenario?
> daytona wrote:

> > Electric hot water tank with timer (Gray Box)

> > >I have hydronic heat in my house and use a oil fired Weil-McClain
> > > tankless boiler that is about 6 years old (WGO Gold or WGTO Gold I
> > > think). It has one output for the hydronic heat and another for the
> > > house hot water...so I don't have a hot water heater. The whole thing
> > > works fine.
> > > My question is whether this is an efficient setup as far as oil usage
> > > goes. The boiler runs year round cause of the house hot water. I know
> > > the heat circuits aren't being used, but it does heat both at the same
> > > time.
> > > I have been considering getting a Boderus direct vent boiler cause I
> > > hate the power vent I have right now and hear Boderus are great
> > > boilers. Would my oil usage be less with a combo boiler/oil hot water
> > > heater year round? I have also heard about indirect fired water
> > > heaters (superstore?). Any experience and suggestions would be
> > > welcomed. I figure I could sell my Weil-McClain cause it isn't that old
> > > and still get a decent $ for it.

Posted by MCO on July 30, 2006, 1:49 pm

I have the same question. I found this reference:

http://hes.lbl.gov/hes/makingithappen/no_regrets/waterheatercombined.html

In summary:

" If you have a boiler or a heat pump for home heating, you can use it to
provide hot water in what is called a combined, or indirect, system. These
systems are more efficient than separate systems because they eliminate the
extra standby losses of another tank or unit."

--

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