Are you kidding? These enclosures let in so much air!!

100% correct
 

As much as I love all things electric, Toymeister is 100% correct here.
The only way to get effective heat from an electric cart is to draw directly from the battery bank at whatever your cart's voltage is, with as Toymeister mentions, much larger/thicker wires. There are only so many BTUs you will get from a 12VDC circuit before your heat source is burned up wires.

How many people had/have a gas stove? Who has run the 18,000BTU oven while boiling water on a 14,000 btu quick burner, heating pasta sauce on a 10,000 btu burner without a second thought in their 10x12 galley kitchen?

Remember, a standard gas range is not vented to the outdoors.

A tiny little 4k propane heater won't generate enough CO in a leaky golf cart to put a mouse to sleep.

If you want a great heater you need the propane heater. I have one and it works really well.

I'm interested if it's still available
 

I'm interested in the heater if it's still available for $35.

I have a Coleman golf cart heater that I’ve used for 15 + years . I can assure you that your concern is a non issue for reasons already stated by other posters . The Coleman heaters are the best with two heat settings but unfortunately, they are no longer available UNLESS you can find a used one on EBay , Amazon, etc…..

Be advised , though, that the battery powered ignition on the Coleman’s do fail BUT they can be ignited by using a long stem butane lighter some use to light the barbecue grills.

There is an alternative to the Coleman and I’ve included an image of that unit . They are sold at SPARR or ACE and run about $100 .

For me, they are worth their weight in gold ! I just used mine during an early morning tee time yesterday morning !

Try Electric Clothing
 

I bought my wife a rechargeable heated vest that she wears under her jacket. She still works and needs to go to work in the chilly mornings. She plugs a USB battery pack in every night and keeps that in the vest pocket. Keeps her warm enough she says.

It mounts in drink holder and flame has cage around it. It if it get jarred it will cut off. Hitting bump will sometimes cut it off. Only thing un-nerving is not knowing out to operate it. I’ve been here 8 years and only three days where I wish I had Heater. But I grew up in northwest Missouri.

I got a gas heater from Lowes or Home Depot for $70 dollars a Couple of years ago. I've used it around 3 times. My Colman stopped working so got this one. In 16 years I have used a heater about 10 Times. When it's cold outside I dress heavier.

Heat up some large rocks in your stove then put them in your cart, should last a couple of hours.:icon_wink:

Electric v propane heater
 

I use propane. It is safe IF you anchor it well so it doesn't tip over going around a curve and fall out of the cup holder. also the CO or CO2 concern while it is burning should not be a problem as the sunbrellas are not sealed very well and let enough air in. If you are concerned put a shim in your front windshield to let in a little air (kinda defeats the purpose of the heater though). If you leave your propane on while golfing in and out of cart make sure you zip up the sides at least enough to keep the inside warm and so the wind doesn't blow the curtain onto burner to start a fire.
Using a 12v/110 inverter you may be able to run a small electric heater. the inverter should have a fuse so you don't blow the main cart fuse. Make sure you get the proper rated inverter for the heater in amps. Don't over work the inverter by drawing too much current. You will be limited in wattage. Carts are just not designed to be heated, they don't have the wiring, fusing, and to leave a heater on while not running strains the battery. The air flow in a cart is not meant to be sealed so the air easily comes in cracks and spaces. the golf cart is not insulated.Any heat is easily dissipated quickly below 40 degrees.

I added a cigarette lighter plug wired directly to the battery.
I have a 12v electric car blanket that I plug into it. Warm enough to counter the chill when it's dark out.