Diesel vs. Propane Heater for Emergency Heating During Winter Power Outages?

I live in Canada, where winters can be harsh, and every year we experience at least one long-duration power outage. I have pets (aquarium, finches, and snakes) that require a minimum temperature to survive.

I’m looking for a reliable off-grid heating solution to keep the main living area (kitchen + living room, ~500 sq. ft.) at around 16°C during outages.

I do have a small 4kW generator, which I plan to use to keep small appliances running (e.g., lights, aquarium heater, maybe a space heater). However, I’d prefer a dedicated heater that doesn’t rely on electricity to handle most of the heating.

I’m currently hesitating between two options:
- Mr. Heater Big Buddy (propane)
- Vevor 8kW Diesel Heater

I’d love to hear from those who have used either of these (or similar models) about:
- Reliability: Which performs better in extreme cold?
- Fuel Storage & Availability: Which is easier/safer to store long-term?
- Efficiency & Runtime: Which provides better heat output per gallon/lb of fuel?
- Safety: Any major concerns (e.g., ventilation, carbon monoxide, fire hazards)?
- Ease of Use: Which requires less maintenance and is easier to set up?

I’m open to other recommendations if you think there’s a better solution. My priority is safety, ease of use, and ensuring my pets stay warm.

Any advice or personal experience would be greatly appreciated!