Hello All & Merry Christmas !

My girlfriend has a small 880 sq. ft. modular home in southern Sierra Mountains , California

She has a small natural gas heater that the blower is no longer working ..... She has been looking for a replacement with very little luck.

We have been looking at portable propane heaters ? and small electric heaters and are just not certain which way to go ?

Any advice on a solution ? greatly appreciated ! I just don't totally trust her home electric system as it's 60 + years old

The temp can get into teens overnight ...... Thank you !

Depends on the type of "Portable propane" heaters you're referring to. Some can be very dangerous in an enclosed area. Any chance of having the electrical system inspected and or Upgraded with a new line and possibly going to a heat pump ?
I heat my 1200 Sq ft shop with 2-4 1500W oil filled radiant heaters but it is extremely well insulated. Normally only get up to 4 in jan- - feb.
each heater pulls 12.5A full bore but they do cycle on & off.

Electric blankets for sleeping are another option for o/nite

880 square feet is about a decent sized garage. Even in ND that size garage only takes about 25,000 BTU/hr. That would mean a unit like this.

Space Heater

Of course, if you wanted more heat, just get a larger one.

Two plug in radiator heaters and a couple ceiling fans to dissipate the heat will probably do the job. Cheap, easy and she likely already has the ceiling fans (any fan, really)...

Small mini+Split may work. Easy to install and safer than a portable. But that goes n
Back to your trust of the electrical system.

Look into a Toyo Laser 531.

I have a larger one in my shop, love it!

I also installed a Laser 531 in my home about a month ago. ( the aging boiler in the basement gave up the ghost last season)

Toyos are VERY efficient.

How dependable do you see your electric grid to be in the future? In most cases, electric space heaters are much more expensive to operate than gas. There are calculators on line where you can estimate your costs each way. Dependability and operating costs would seem to be at the top of the list.

We have a geothermal system and a couple of propane space heaters. We LOVE the propane space heaters. They really warm our old bones and do it quickly.

Look up the Mr Heater line of propane heaters - I've used one indoors without problems.
I'm disposed against electric heat due to operating cost and power failure in stormy times.
A proper gas furnace would be best, I think - sounds like she'd have to run propane if there's no NG service.
Wood heat is dead-reliable, but that means installing a wood stove & maintaining a supply of dry wood.
Whatever you do, have proper ventilation.

I would look into a high efficiency mini split for configured for low temps.

It would probably be wired directly to the panel and lower the risk of electrical issues.

Have someone look at the current heater. There is a a small heat switch/thermal switch that is usually the issue. the switches are inexpensive and I bought mine by the dozen because they are known to go bad.

Like topside said. Mr Heater are indoor capable.

I just used a Mr Heater Heater in a friends greenhouse while I got the electrical squared away.

I bought the one that uses Two 1 lb canisters then added a filter and long hose kit. The long hose lets you hook it to a 20lb or larger tank (the tank should be placed outside) and the filter keeps the oil that is present in refillable propane tanks from messing up the heater. Has a low oxygen shut off and did a bang up job. No electric required but electric can be used to power a fan to boost it's efficiency.

Just an FYI hope it helps.

How have heating fuel prices been going up there? Here it's being priced out of the market so I'd guess California is the same.
How often is the heat needed? I'd be tempted to go electric. Did you check if you could replace the blower? Usually that's a pretty cheap option if you can find the part or find a place to fix the motor.

For Christmas among other presents you can get her a CO detector.

What is the altitude there? Some gas heaters don't work well above a certain altitude.

7000 Ft. ........ she's aware of this problem and has decided to go with couple electric heaters and get someone to check out

the fan for replacement / repair ........... THANK YOU ! to everyone contributing their knowledge on her problem

Electric base board heater might be another option once the electricals' checked out