Inexpensive, direct-vent backup for tarm solo

[MrEd]

Hi folks.

In my never ending pursuit of figuring out what to buy, I am pretty sure I will get a solo 40 (with or without tank at first) and one option is to put it outside, and do the whole underground pex, anti-freeze thing....

The other option (since I don't have an extra chimney in the house), is to simply decommission my old oil boiler anyway, and re-use the chimney that is there. We are almost always home, but sometime do go away for 2-3 weeks in the winter (New England winters)....so I would need a backup.

What is the cheapest boiler/heater that I can purchase, that wouldn't need a chimney, but could seamlessly kick-in when the tarm is not running? If I go with the outside boiler (Tarm in a shed), this would be a none-issue, but if I put the tarm in the cellar, I need another backup heat source "just in case". I'd like it to be able to plumb right in with my tarm, DHW and cast-iron baseboard system.

The backup doesn't need to be the cheapest to run, just the cheapest to purchase and install...99% of the time it won't be used anyway...

 

[Nofossil]

Maybe a propane fired on-demand hot water heater?

 

[ssupercoolss]

i am looking at a harman boiler, that has an electric back up. 2 4500 watt heating elements. i think it would be really expensive to run this way though. the fuel cost calculator has it at $43 for electric, and $28 for fuel oil. it does have its place i guess.

 

[JDenyer232]

Electric baseboard strips would be the cheapest to install but more than likely the most expensive to run. A direct vent monitor heater might fit the bill.

 

[jebatty]

We put in a millivolt thermostat (thermocouple) LP space heater. Killed two birds with one stone. Backup heat when needed (will keep house above freezing but not to a comfort level) and works even in the event of a power outage. It is direct vented outside through a wall, have a 100 gal LP tank. Since it has a pilot light, we only turn it on when we are going to be gone for more than a few days in the winter. If you have a large space to heat, will need good convected air flow to get the heat around the house.