Saving Energy with Oil Fired Boiler for Hot Water

[Gadgetnut]

I have a thirteen year old Weil-McLain 115,000 btu/hr oil-fired boiler that is used to heat water to provide infloor radiant heating to a medium sized house. Two years ago I eliminated two 80 gallon electric water heaters that provided domestic hot water and installed a 79 gallon indirect water heater in tandem with the above boiler.

When I go away for vacation I turn the entire system off. When I've turned the boiler back on from cold, I've noticed that the hot water recovery time from cold is quite fast-- hot water within the hour.

After the heating season was over, for the three months mid-April to mid-July, I used 160 gallons of heating oil to run the boiler, just for domestic hot water. Two people at home, don't use a great deal of hot water.

I read that indirect water heaters were efficient, but I notice my boiler running many hours a day and the utility room the boiler is in is very warm all the time from the boiler running. There is no infloor heat demand in the summer, so only reason boiler is on is to satisfy the indirect water heater.

I imagine this older boiler is not very efficient and being large enough to heat a whole house, it's overkill for just the hot water heater's needs. At $2 a gallon, I'm spending a little over $100 a month for hot water heating for two people.

(I am familiar with the on demand, point of use hot water heaters... I don't have natural gas, and not a great source of propane either. Don't know if there are electric on demand water heaters or if there's any point to that.)

We only need hot water in the morning for showers, after that warm water is sufficient. I have a timer that can turn on the oil fired boiler for just three hours, 6am to 9am... will this hurt the oil fired boiler to let it cycle from hot to cold and turn it on and off again everyday-- or is this just a boiler cycle which is a boiler cycle and it doesn't matter?

It may not save any heating oil to heat furiously for three hours then nothing for 21 hours, but if this pattern won't harm the boiler I may try it for a couple months and see what the change in consumption is. Thanks for any input.

 

[Highbeam]

The indirect heater is only efficient when the boiler is already running for house heat. The rest of the year it is a pig as you found out. Many folks are either dumping these indirect heaters entirely or are using a two tank system, switching between one indirect tank for winter and one electric for summer. The extreme waste of your current setup will allow for a rapid recovery of the purchase price of the electric tank heater. Also, you will have a redundant system to allow for a backup water heater should one tank fail.

 

[LBrown59]

I have a thirteen year old Weil-McLain 115,000 btu/hr oil-fired boiler that is used to heat water to provide infloor radiant heating to a medium sized house. Two years ago I eliminated two 80 gallon electric water heaters that provided domestic hot water and installed a 79 gallon indirect water heater in tandem with the above boiler.
We only need hot water in the morning for showers, after that warm water is sufficient. I have a timer that can turn on the oil fired boiler for just three hours, 6am to 9am... will this hurt the oil fired boiler to let it cycle from hot to cold and turn it on and off again everyday-- or is this just a boiler cycle which is a boiler cycle and it doesn't matter?
It may not save any heating oil to heat furiously for three hours then nothing for 21 hours, but if this pattern won't harm the boiler I may try it for a couple months and see what the change in consumption is. Thanks for any input.

Did you know you can also run your tractor on this too ?

 

[Egon]

We have hot water heating in our house. The Saturn boiler has a built in domestic hot water coil. The furnace will cycle on to keep this coil hot but it only takes a few minutes and does not cycle often.

Of course if there is a demand for domestic hot water the boiler comes on and runs.

 

[Gadgetnut]

To Highbeam: Thanks. No kidding, running boiler all summer just for hot water is an extreme waste. I've had the boiler on a 3 hour timer the last two days and I don't notice any difference in hot water delivery. I just hope I'm not harming the boiler to allow it to cool off everyday like this.

To LB: yes, I am using this "heating oil" in my Bobcat ToolCat and in my Walker (Kubota diesel) lawn mower with an electric, auto shut off fuel pump, super convenient. (By the way, guys, I subtracted my tractor fuel consumption from the hot water heating calculations for this discussion.)

To Egon: I know what you mean... in the summer you wouldn't expect your boiler to run all the time just to satisfy the domestic hot water, but my boiler seemed to be running day and night, that's why I put it on a timer for 3 hours a day... we'll see what the fuel consumption does and I'll report back. So far, the quality of my hot water experience has not diminished at all.

 

[TUG HILL ADDICT]

Just for comparison...I heat hot water with oil...family of 5...we consume about 250 gallons of oil in a year

 

[Gadgetnut]

Tug Hill Addict, thanks for the comparison, that's useful. As Highbeam wrote, I'm realizing the boiler is a pig during the non-heating season. Beautiful signature photo by the way. We had an, I'm told, uncharacteristically heavy snowfall last Christmas and I used the combo bucket on my Bobcat ToolCat for the first time to move lots of snow.

 

[LBrown59]

To LB: yes,
* I am using this "heating oil" in my Bobcat ToolCat and in my Walker (Kubota diesel) lawn mower with an electric, auto shut off fuel pump,
** super convenient.
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*It's surprising how many people that Have a home fuel tank don't do that because they don't realize that what they are heating their home with is the same stuff they run in their tractor only thing is they run after it fighting and fumbling with 5 gallon cans while paying 35 to 45 cents more per gallon for what they already have setting in their tank at home.
**Cheaper and time saving too,

 

[LBrown59]

Just for comparison...
1*I heat hot water with oil...family of 5...we consume about 250 gallons of oil in a year

Do you use it in your tractor also.?

 

[Duffster]

Do you use it in your tractor also.?

LB

I don't use fuel oil in my tractors.

But I do use offroad in my furnace!