How many space heaters to keep house from freezing?

Coal eh?

Quick tip, a desktop computer is, from a thermal perspective, a space heater somewhere in the range of 250w (typical cheapo) to 1kw (high-end gaming PC). You have to run them flat out to get the full capacity of waste heat out of them - you can use a benchmarking/stress testing tool to run the CPUs and GPUs flat-out, or do something more productive, like a BOINC distributed supercomputing task, or if there are no more helpful options, mine cryptocurrency.

In reply to tr8todd :

These are all good points, I had not thought about filling the tubs and sinks.

I hadn't thought about it too much but the boiler does pretty much always bottom out around 50F when it's off.  Both the hot water circulator and the house circulator were on, effectively heating the house slightly using the "heat" in the basement and water supply.

I didn't realize it would still circulate.

Is the boiler like a typical hot water heater system?  Does it have a port where you can you just put in a supplementary heating element for $10 and plug it in?

For future reference I wouldn't hesitate to run a couple (reasonable quality, in good repair) electric space heaters in this situation.  Place them away from combustibles on a hard surface floor.  Those things have gotten a bad rap, but they start fires because people are stupid, not because they burst into flame if you look at them funny. 

You're not trying to make it comfy, just keep it above freezing.  Set all your faucets to drip, it will keep the pipes from freezing.

In reply to ProDarwin :

It does not have a port but they make some that get plumbed into the line.  They are certainly not $10 and would require 240 to be run.  

We planned to install a few electric baseboards throughout the house because it would save us a bunch on insurance.

I bought the boiler I did because you can get an oil burner for it.  I have all the parts except the special door.  I had planned to modify the one I have but this might motivate me to order one.

Too funny.  I gave advice and woke up to a cold house this morning.  Ran out of oil in the night.  Turns out being home for 4 weeks recovering from surgery with the heat cranked instead of heading out to work every day actually burns more oil.  Who would have thought?  Had to run out to work early but finally got the oil company on the phone.  They might be able to make it Saturday.  Turned on a small 1000 watt heater, opened the shutters on the sunny side of the house before I took off.  When I left it was 52 degrees.  When I got home it was a balmy 36 outside, and downstairs of my house got up to 62.  Grabbed 10 gallons of diesel and got the boiler fired up before dinner.  Yeah, warm house, warm shower before bed.  Expecting 6 to 10" tomorrow so probably going to have to make another diesel run.