Multi fuel boiler, or a wood boiler plus a gas/ oil boiler

[AQUALUNG1919]

I am planning to build a new house this coming spring and am planning to use a wood boiler to heat, however the bank needs an alternative heat source to wood. I have found a TARM SOLO 40 used for cheap. Sould I get that plus a cheap gas/ oil boiler. Or should I buy a multi fuel boiler?

Thanks,
Adam

 

[Gooserider]

I am planning to build a new house this coming spring and am planning to use a wood boiler to heat, however the bank needs an alternative heat source to wood. I have found a TARM SOLO 40 used for cheap. Sould I get that plus a cheap gas/ oil boiler. Or should I buy a multi fuel boiler?

Thanks,
Adam

You will find folks that argue each way, but IMHO you are better off with separate units...

1. It may well be cheaper to purchase two separate boilers, as the combined units tend to be expensive. This can especially be the case at replacement time, as you'd only need to replace one side at a time (hopefully)

2. Redundancy is nice - with a combined unit a failure leaves you with no heat, with separate units a breakdown on one leaves the other functional.

3. The combustion requirements for each fuel are different, and generally the compromises needed to burn both will lead to less than optimal efficiency from one fuel or the other.

4. Unless there are separate combustion chambers, the fossil burners can easily be messed up by wood ash and other combustion debris, or damaged by fuel loading.

5. Given the newer wall-hung compact fossil boilers, you won't really save any space over a multi-fuel unit.

Etc...

I really don't see a lot of advantages to the combo units other than the possibility of venting them into a common flue, and IMHO that is only useful if you can't wall vent the fossil burner for some reason.

Gooserider

 

[heaterman]

If you can find a multi fuel like a Tarm or equivalent you'll probably be satified with the performance. DO NOT buy any outdoor wood burner that has multi fuel capability. I have never tested one that runs over 50% efficiency when burning oil or gas. I remember one in particular, a HeatSource 1 that ran an even 38% efficiency on propane. OUCH!! I have a customer with an old tarm fuel oil/wood combo in his basement that does pretty darn well. The original Carlin oil burner gave up the ghost and we installed a new Riello F-3 burner on it. That thing ran an honest 82% eff on the combustion analyzer firing into 160* water. Not bad at all for a multi fuel config.

That being said, my personal choice would be two separate units for a lot of reasons

 

[muncybob]

Although I did install an oil/wood boiler I would have preferred 2 units. For me, the cost of a new chimney (for 2 flus) and limited space in my basement were the deciding factors.

 

[ISeeDeadBTUs]

You're skating away on the thin ice of a new day!

I have separate units, but I like my wood outside. Pros and cons to that.

May I assume you will be doing radiant heat? If so, I would not recommend spending big bucks on a fossil boiler. Spend the saved money on storage.

Not sure how ready I'd be to buy a used boiler.

Hmmmm . . .