The #1 thing you need is insulation and leak sealing as Ecnerwal discusses at length.
You should also review the performance of your heating system. I had a gas boiler growing up. It needs to refill itself with water from time to time. It's also important not to block baseboards - they need air circulation if you want them to work.
But I mainly want to talk about tripping circuit breakers
Tripping circuit breakers is SUPER BAD. It means you are already overloading your electrical system and you need to stop Right Now. My winter cottage has 30A/120V service with only two 20A circuits for the whole house. Yet we have had three breaker trips in 15 years because we know where our circuits are, how much power they have, and how much power our stuff takes.
the circuit breakers turn themselves off (5-6 times per day, usually).
And you resetting them over and over is you actively trying to burn your house down. When a breaker trips a second time in a year, you stop using the circuit until the problem is identified and permanently resolved.
I am pretty close to trying some propane powered indoor space heater, but I do worry about safety with anything like that.
No, trust me... you do not worry about safety. Why start now? LOL
Figure out your circuits, then figure out your loads.
So that's what you do. Take a few hours and shut off breakers one at a time, and see which lights and outlets die. The lights aren't consequential but you should know every socket and hard-wired heat making appliance (so microwave etc.). This outlet is on circuit 3, this one is on circuit 7 - or you can name them like Thor, Hulk, Ironman etc. Your call.
Then, look at your appliance' name plates and see how much power they take in amps.
- Newer refrigerators are too little to matter.
- Cell phone chargers, cable box and TV are too little to matter.
- The clock on a gas range is too little to matter.
- Anything that just doesn't make much heat is too little to matter.
- Inkjet printers don't matter. Lasers do.
- PCs vary a lot.
- Microwaves and hair dryers can be 1800 watts (15 amps).
- Space heaters are all 1500 watts (12.5 amps).
- Other heat making appliances vary between 5 and 12.5 amps.
If you can't be bothered looking at nameplates, you can get a "Kill-A-Watt" home energy monitor for $30 and it will tell you what the appliance is taking right now (which doesn't necessarily mean what it always takes). Put a Kill-a-Watt on a PC and note the amps. Now start up a graphics-heavy game and note the amps again. Surprise!
or if some smart device turns itself on
If a high load device is under automatic control, you need to figure like it's on all the time.
Then think about amps when you use your loads.
The circuit breaker handle states the amps the circuit can safely handle - it is 15 or 20. Hopefully no fool enlarged the breakers improperly.
Think about every load active on the circuit before you switch on anything else. That space heater is 12.5 amps which pretty much dominates a 15A circuit. It can share a 20A circuit with a few small things but not another space heater.
If you want to make toast and there's a space heater on that circuit, well, the nameplate or the Kill-a-Watt has told you the toaster is 7 and the heater is 7 or 12.5. So 7+7 works so set it to low.
If you're putting 2 space heaters on 1 circuit you are pulling 25A on a 15A or 20A circuit, which rhymes with "I WANT to burn my house down".
It's like this except a modern fridge and freezer are only 1's. And you have 15 or 20 per circuit instead of 7.
How are you paying for all this stuff, anyway?
Let's face it, Mr. Moneybags. You obviously have GIGANTIC electric bills from all this electric toaster heat. And you're spending money on gas. And now you want to be buying 2-3 of those propane bottles per day per heater at $5 a pop?
See, that doesn't make any sense. Plenty of $ for gas and electric but not a penny for insulation or sealing or fixing your furnace or better yet, get a modern heat pump?
https://www.youtube.com/watch?v=7J52mDjZzto
Because they're really quite good now.
And I bet you have months with nearly $1000 heating bills. Heck, a DIY mini-split is less than that, you could install one a month. Now you need a little bit of A/C skills and you're not allowed to play with Freon directly, but they have that figured out.
https://www.youtube.com/watch?v=Kd092alkeaE