An electric mIni-boiler for winter baseboard heat to supplement heat pumps

Ajay

I have a two-story country house - originally a carriage house converted to a residence in 1957 - that was heated with an oil boiler that sent hot water through a loop baseboard system.  Each floor was its own zone.  It worked pretty well, even though the house is built directly on slab - no basement, with a crawl space at one end - and 2/3 of the 750 sq. ft. first floor is brick, which is very cold in the winter.  
The baseboard heat also served to prevent the water line to the kitchen from freezing when it got really cold - the water line runs right on top of the baseboard,   
Two years ago, we installed heat pumps and a generator to back the system up in the event of power outages - quite frequent here in the Hudson Valley.   But since heat rises, the mini-splits weren’t heating the air near the floor, and when it got really cold we supplemented that heat with the boiler and the baseboard heat.  That worked fine.
But last year we were advised to stop using the boiler, which is quite old, because it was on the verge of cracking.
Sure enough, we had a pipe freeze and leak last week in the water line.  
I’d been thinking about getting an electric mini-boiler just to run the first floor baseboard zone, but hadn’t known enough to make a decision.  So, I’m serious about that now.
My plumber, after he’d repaired the water line, suggested just keeping a fan running to blow ambient warm air over to where the line runs.  And he added that since we’re not here most of the time, a mini-boiler wouldn’t ever come on if the thermostat was set for a temperature lower than what the heat pumps were delivering, which would mean that it would have to be set higher than that and would therefore be running all the time, and that would be very expensive.
What I forgot to mention to him is that we have a Nest thermostat, which enables me to keep it set low most of the time and to be able to remotely raise the temperature when the weather gets really cold.
Perhaps he’s right about the fan, in terms of preventing frozen pipes.  But there’s still a need for baseboard heating to supplement the heat pumps just in terms of comfort levels on the first floor.  The baseboard infrastructure is there, and it seems like a waste not to be using it.  
Can anyone suggest what technology and brands of electric mini-boilers would make sense?  
Many thanks in advance.

Hot_water_fan

A small electric boiler would be fine! Also consider just installing electric baseboard - same efficiency, less complexity.

mattmia2

Could put a fixed thermostat set at 40 or so near where the pipe that freezes is and put it in parallel with the room thermostat.

Not sure what the "on the verge of cracking" means. Usually that would be a replaceable part like the refractory or the vent. Might want a second opinion from a good oil burner tech on that.

hot_rod

If the fin tube is in place and not leaking, adding an electric boiler would be easy enough. Probably not the most cost effective energy? A gas, LP or oil boiler may be a better long term investment?

Thermo 2000 has some very nice electric boilers in all sizes.

wwwthermo2000.com

Jamie Hall

Check your energy prices very carefully. In your area you may find that the energy cost of replacing the oil boiler with an oil boiler will be much less — like as much less as a third — of the cost of putting in an electric resistance boiler — and probably not much more, if any more, than running the heat pump to keep the base temperature of the house.

Which is what I would recommend. Figure what size oil boiler you need and install it in place of the old one. Set its thermostat at 45. Let it run.

GroundUp

If electric rates are at an acceptable level, electric boilers can be a fantastic option for things like this. Electro Industries is easily the best electric boiler on the market in my opinion, and I've got hundreds of them in service with only a handful of repairs needed in my 15 years of using them. It'd be simple enough to use your Nest to turn it on remotely, or have a separate thermostat for the electric boiler only located down at a lower plane to maintain temp below the heat pump's level of effectiveness. I've got a couple set up like this in hunting cabins. Otherwise perhaps a large ceiling fan to push some heat downward?

Hot_water_fan

If the goal is to protect pipes in 1 room, I wouldn’t spend much money on a boiler here. This is a cheap fix and heating 1 room to 50F or whatever you decide will be minimal. Or you could drain the pipes.

Jamie Hall

Electric rates where our OP is located are not at an acceptable level — somewhere around $0.30 per kWh at last count, and going up. Again. A really good heat pump will break even with oit, more or less, at that price — but a straight electric boiler will be a nightmare.

I still would ask: what is the reasoning behind not replacing the old oil boiler… you can even run it on a generator when the power goes out (which it will, at oh dark hundred and 10 below) if someone is available to get the generator going. And you won't freeze the plumbing.

Hot_water_fan

@Jamie Hall you gotta think of total cost of ownership here. No doubt oil is cheaper than electric resistance per MMBtu. But how many MMBtu are we expecting to keep 1 room above freezing? Spending$10k to save $50 (purely made up numbers) makes no sense.

hot_rod

It sounds like a two story house with hydronic heat that is still a viable system? So a new boiler takes the ineffective mini splits out of the way.

Put your fuel costs into this calculator

https://coalpail.com/fuel-comparison-calculator-home-heating

Jamie Hall

I guess I'm a bit paranoid sometimes, @Hot_water_fan — but I've seen one too many houses become a total loss because the plumbing froze. The scenario goes like this: cold weather. Power fails. Electric heat. Plunging freezes. Power comes back on. Heat comes up. Plumbing thaws. Three days later someone notices that there's water coming out from under the front door.

Total loss. True, it doesn't happen every year. In the last five, there have only been three in the area we live in.

For a total loss of about 2.6 million dollars…

Now having oil rather than electric won't necessarily prevent that — but unless it is just one room (as you suggest) and no plumbing elsewhere, you can't run enough electric heat on a normal generator to avoid the problem. Of course, if you are out of town and don't have someone to check on the house… you're toast anyway. Your Nest or other 21st century magic wizard may tell you that your house froze — after the power comes back on and your wi-fi reboots — but unless you can get there in two or three hours… hope you have a boat.