Unattended Space Heaters

My sister-in-law, call her Sue, rents a suite of rooms the basement of our house. She pays, but not the commercial value, and doesn’t chip in for utilities. She claims the rooms are uncomfortably cold all seasons of the year. She bought a portable Delongi oil filled space heater to warm up the rooms.

Now, all the fire and safety procedures I know about recommend turning off space heaters when you leave the house. Sue, however, believes it is fine to leave the space heater on unattended, just as long as the setting is turned to LOW. I told her could only keep it on all the time if the owner’s manual said it was safe to do so, but she’d thrown it out. I even called the manufacturer myself and they said the heater should be off when nobody was home.

I’ve had a long running battle telling her to turn off the space heater whenever she leaves the house. Either she really can’t remember to turn it off, or she decides to leave it on anyway. For awhile, last winter, I had to enter to room and turn it off myself everyday. After some terse and stern words she agreed to keep it off when she wasn’t home. She seemed to comply and I stopped checking up on her. I thought the trouble would end with winter. But, no, Sue is still “cold, uncomfortably cold” in the basement. She runs the space heater every day. Yeah, I know, it is August, but she says she is still cold in the basement.

I thought, however, she’d learned to turn it off when she left. I was mistaken. Occasionally one of our cats goes into her rooms and I need to go in to get the cat out. I still find the heater on from time to time. I try not to entering her space whenever avoidable, but she has proven to be untrustworthy in the past, and I think she is back in the habit of leaving it on 24/7.

So how can I get her to turn off the bloody thing whenever she leaves? I’m not her daddy and shouldn’t be the custodian of her heater. Words doen’t seem to last. I’m thinking about removing the heater from my house entirely. Let her be cold if she can’t operate equipment safely.

Or am I (the manufacturer) just overly cautious? Should allow her to run the heater when no one is home? She works 2:00 to 11:00 and likes to return to a toasty room.

My wife agrees with me, or so she says, but doesn’t want to confront her sister over the issue of the space heater. Sue also had an upstairs bedroom for a few months, but decided to move to the basement for more privacy.

I don’t know how safe it is to leave the heater running unattended (I wouldn’t do it), but would it be possible for you to turn the heater on for her about 1/2 hour before she comes home? That way, it wouldn’t be running all afternoon/evening and her room would be warm when she got there. Maybe if you all came up with a different solution, she wouldn’t feel the need to leave it running.

I use one and when I’m done in the room it’s in, it gets unplugged even though it has a tip-over safety switch.

This thread from Janurary might help.

We have one of the same oil-filled DeLonghi heaters for the bedroom in the winter, but it doesn’t get turned on until an hour before bed, and gets turned off after we get up. It’s the only kind of heater I’d buy - anything that glows red is not coming into my house!

I can’t imagine leaving it on all day! Can you imagine how much electricity it wastes heating a space with no one in it?

Honestly, if it were me in your situation, Sue would be getting a sweater and an extra blanket, or a new apartment. Screw the fire hazard and the gargantuan utility bills!

Or exchange it for a DeLonghi heater that can turn itself on.

The instruction manuals are accessible on the Delonghi web site. You might have to print pages out to be able to read them.

Relevant items, from safety page:

This is from their FAQ page:


If she doesn’t want you in her space, could you put the thing on a timer that would turn it on just before she gets home, and would turn it off when she’s not scheduled to be there?

Also, if this is a long-term living arrangement, would it be worth having a wall heater permanently installed, with its own thermostat?


Just Google the words ‘Fire caused by heater’ and you will come up with many examples of what you don’t want to happen to your home and the people in it. Show her a few of the more graphic examples. The closer they are to your location, the more it might sink into her thick brain that heaters left on are not a good idea.

We use heaters, too, and we don’t even leave them on while we’re sleeping. I turn the ones in our bedroom and our son’s bedroom on about an hour before we go to bed. The one in my son’s bedroom gets shut off when he goes to bed and the one in our room gets shut off when our light goes out. We dress warmly for bed and have a good goosedown comforter (and wool underlays on our beds), so we all stay pretty warm.


Don’t let her do it! We had TWO fires caused in my apartment complex last year by those goddamn unattended space heaters. Both apartments were completely gutted. I’m just grateful it wasn’t in my building.**

I’m going to check her room when I get home tonight. Hopefully, it will be off. If it is, I’ll say nothing for now. I’ll be out of town the rest of this week and Sue is taking care of the cat beasts. But that is just putting off the conflict.

I wonder if the local fire department would be willing to give her a “friendly” call about safety practices. I’m sure they’d rather prevent a fire then put out a fire, but I’m not sure if they do anything to help.

I’m not sure how much the space heater burns up in electricity. I’m guessing only $50 to $60 per month, but I’ve only been in the house a 1 ½ years, and she been there from the beginning, so there is no data to judge the higher costs against.

Thanks for the links, ** observer11 **. Maybe a wall unit with Automatic Temperature Shut-off would do the trick in the long run. Either that or find her a rich husband. (Sue would never consider a man as potential husband who didn’t have money. Any wealthy takers? She is pretty as can be outside the glamour professions, early thirties, but lacking basic common sense and susceptible to cold temperatures.)

Well, as to cost, space heaters are generally either 750 watts, or 1500 watts. If on 24/7 for a month, we’re looking at 540/1080kW hrs (for 750w/1500w respectively). I’m paying 8.75 cents/kWh, which would put the cost at 47/94 bucks a month. However, most of these things are on thermostats and don’t run full time. Plus we’re only talking about the hours when she’s not home. So let’s assume that the thermostat only kicks it on about 50% of the time, and it’s unattended 8 hrs a day. So then we’re only talking about 4 hrs/day difference, which comes to 8/16 dollars a month of savings.

Naturally, your electrical rates may vary.

Go halvsies with her on a small furnace that is hooked up to your gas line. A space heater is nothing to mess with. I’m sure she’ll opt for that over a cold basement (which should be her only other option).

My husband used one to warm the bedroom in his house before I moved in. The cat was singed one time. I told him after that first winter, it’s a new furnace or we’ll have to have separate living arrangements. I was freezing and scared of going up in flames!

What about a timer that would enable her to leave it plugged in but set it to turn on shortly before her arrival home?

Firstly, I read the title of this thread out of the corner of my eye as “Unattended Space Hamsters”, which was kind of cool.

Secondly, I’m in the “she should turn it off when she’s out” camp. And put on a sweater, look for an apartment, something like that. But the suggestion to get a heater with a timer might be a good compromise position for the moment.