Heating Garage /Semi Insulated

Seems a few of us have the same idea. I am also looking for a garage heater with the following specifications:

1. I live in NE Ohio which is in zone 5. It doesn't get super cold, but I would like to maintain at least 50-55 degrees F during the winter to keep the cars comfortable in the morning.
2. 2 car, single door garage. Garage is attached and around 525-550 sq ft, with 12 foot ceilings.
3. Garage door is brand new, 2 inches thick and R12 insulated. All edges are sealed.
4. I am pretty sure the walls and ceiling are insulated because our main bedroom is above the garage, and the bedroom floor is warm and the room has stayed warm during these past few colder days.
5. There is a single exterior door that needs to be replaced because it is older and is on the south side of the house (the frame is starting to go). This is currently covered because of a few small gaps.

With that said, I have found a few options and am leaning towards electric. I do have natural gas but I don't like the idea of punching a hole through my wall for ventilation. I found this one to be well rated

$240 Fahrenheat FUH Electric Heater for Garage, Factory, Basement, Warehouse, and Outdoor Use, Beige

https://www.amazon.com/Fahrenheat-FUH54-240-volt-Garage-2500-5000-watt/dp/B0000AXEZV

What are everyone's thoughts? Should I just get a natural gas heater?

 

Super low tech solution, but I use a pair of these to heat my garage:
DeLonghi TRD40615T Full Room Radiant Heater

$130 De'Longhi Dragon Oil Filled Radiator Heater, 1500W Electric Space Heater for indoor use, portable room heater, programmable timer, full room heater with safety features, TRD40615T

https://www.amazon.com/dp/B00FT5VAWI/ref=cm_sw_r_cp_api_kGgtAbCV0NTQN

They are silent and programmable, there is a more expensive one with electronic digital thermostat if you want it to be more automatic. These ‘Dragon’ heaters put out noticeably more heat than a normal electric radiator heater.

My garage is a about 575sq/ft. It has insulated twin doors, on a non-insulated wall, side walls are concrete with the back wall insulated living space. The roof is half insulated, under a living area, and half not insulated under a flat roof deck.

With below freezing temps outside and both heaters on max it is more than comfortable to be in the garage with jeans and a T-shirt and can actually be difficult to wear long sleeves.

Pro is they are portable, inexpensive and silent, so you can use them for other things if not needed in the garage.

Con while being efficient, they take a little while to heat up a space and they do use floor space when in use. Not a big deal if you set the timer or turn them on in advance, but don’t expect to turn them on going into the garage and have it warmed up in 15 min.

Note that to use 2 you will need 2 available circuits in the garage.