u/Responsible_Ad8233

My home gets extremely cold in the winter due to poor insulation. My electric bill was 700$ in December to warm a 3 bedroom house with 1 person living in it to 50° Fahrenheit. So my primary objective is-

1. Cheap to free creation of heat (I have no money)

2. Keep my pipes from bursting ( I have a crawlspace/basement I can access from inside the house that I can crouch-shuffle thought easily enough.)

3. Prevent a flame from being inside the home or cause noxious/dangerous fumes (Id probably burn my house down if I used a diy heater)

My plan is to heat stones specifically Concrete Retaining wall block from home depot in my fire pit outside, (I have 100 gallons of used motor oil I'd use as fuel) then bring them inside and place them in a metal basket (picture a kids shopping cart sized object made of bar stock) and let the heat radiate off the stones to heat the rooms i need. The basement/crawl space is w35' x L25' x H3' and the bedroom is w10' X L15' x H10'

Concerns/advice/ better solutions are all appreciated.

I've got a bunch of used oil (100gallons) but don't particularly want to use it directly in the home to heat the place because I'm really just there to sleep and I don't want to get carbon monoxide poisoning in my sleep from a bad flute job or accidentally set the place on fire diying a oil heater. I'm thinking use the oil outside but to heat up some rocks or something then drag those into the house so I can sleep without worrying the place is going to burn down.

Any recommendations? Is this a problem a medieval peasant figured out and I'm just to big for my britches to figure it out?

edit: a key piece of information I forgot to add was I need to be able to prevent the pipes from freezing in the basement. last year my house got down to 20° Fahrenheit at some points before I got my emergency heater "fixed"