Consumer reports rated space heaters for safety in their November issue. I am no longer a subscriber, but can access it through our library online - your library might have the same option. Or perhaps someone here is a member and can give you the info on their suggested best and safest models.

https://www.consumerreports.org/space-heaters/space-heater-safety-tips/

Is there a reason the room doesn't have heat? Is it just the expense? I'd look into extending your existing technology, be it hot air or baseboard or whatever, or look into another option such as radiant floor heat or a heat pump unit, to provide more substantial and lower risk source of heat.

Those other heaters scare me. I have a quartz heater that I use in my craft room (it's in the lower level that we don't heat) but only when I'm consistently in the room to keep an eye on it, never as an "automatic" source of heat.

What type of heat plant do you have for the main part of the house? Can it be extended to heat the guest room?

If you cannot extend the existing house heating system to the room you could use a ductless mini split system for that room. That would eliminate needing the air conditioner in the summer since a mini split functions both as heating and cooling.

Also, I thought mildew was a function of moisture more than heat. I understand raising the temp will lower the humidity, but if you could just lower the humidity more, you might avoid needing to heat it and have no mildew issue.

I highly recommend asking your HVAC service technician if his company would do a whole house survey. The president of the company I use did this for me and planned out changed to the system that have made a world of difference.

Susan is in a century old house. The wiring is maybe not up to standard of today. I would leave the door open, and set a fan in the doorway to do an air exchange.

Moni

PS, I think, she uses a stand alone wood fired heater in the main part of the house.

Lots of places have this same problem. They make an electric wall heater with a digital setting. We had one when I was a kid(not digital) in my grandmothers room. She was always cold. Worked great!

This one can be installed in the wall between studs. It's rated for commercial applications. Electric wall heater

I agree that you need to address the moisture issue. Does the dehumidifier not do enough? That is, you're worried it won't be enough or you already have mildew again?

On dive boats, they use these dehumidifier bags. I do as well.....along with a fan to create air circulation, it draws air across the room and out a vent...in my vault room. I have a humidity sensor that automatically controls the fan.

Annie, that's an interesting point. I could put a dehumidifier in there in winter. They generate some heat on their own, and yes, the lower humidity should take care of the problem.

Watchmelol, I never heard about a mini split, but I can ask my heating guy about it, especially if I ever have a guest in there in winter.

Olychick, I'm at the library regularly and I think I can access Consumer Reports from there. I'll check it out!

My house is a c. 1850 farmhouse. As long as I've been here (since 1975) we've never had heat upstairs. When we heated with wood (until a couple of years ago) we got sufficient heat through the floor grates, but now I'm using the oil burner instead. I pre-heat my bedroom with an electric radiator, and turn it off when I go to bed.

Thanks, everyone!

I saw only the first six posts when I wrote mine, above. This house is um . . . unusual. Most of the walls don't have studs, as the house is a double plank construction (wide hemlock planks). In this rural area, my HVAC service technician's company is himself. I don't have mildew yet; I was just planning ahead. But I think the dehumidifier might be all I need. Thanks again!

Olychick, the CR report you linked is much more extensive than what's available in the Nov 2019 issue. All they listed there are the names of the top 3 in various categories. I had to flip through the magazine 3 times to find it; that's how small it was.

We have a small space heater we use in the bathroom only when it's very cold to take showers but I could never use one to heat a room where I either wasn't going to be in it constantly to supervise or especially not to fall asleep in.

Running just a dehumidifier in the room should help with the humidity/mildew. They can kick out a little heat too.

Up here in snow and cold country, I have trouble with mould in the basement and in some unused rooms in summer, and use dehumidifiers.

But in winter our houses get really dry as the cold air coming in can carry only very little moisture and when it gets warmed sucks up all of the moisture that it can find, so they tell us that many of our houses have lower relative humidity than the air in the desert.

o j

chipotle, that's strange, no? I wonder if their online report is more extensive than the magazine? I can't access the full report or ratings online because I don't subscribe, so I just figured it would be available in the magazine.

I wonder if until something more permanent could be worked out, a marine mold/mildew buster might work in one room for you. Do I understand this is the only room upstairs that has a problem?

My BIL keeps something like this on his boat in winter. It's moored, floating, in an unheated boathouse. Bedding, windows all stay fresh and dry and I think he's said it costs about the same as leaving on a lamp. It's on all winter other than those few nice days they find to take it out and run the heat. It doesn't have a fan so not much to break, it just emits a barely noticeable slight heat that manages to move the air a bit.

Marine style mold mildew preventative

A humidifier doesn't work well in cold areas. When I lived in northern Oklahoma we had a full basement with humidity problems. The humidifier would freeze up in the winter, as we didn't have a heat/ac outlet down there.

Moni

Morz, that is a very interesting contraption! I wonder if it would work in my small bathroom, which, even with a fan, has a tough time drying out after showers.

I have a pick-up truck that sits outside year round in our rainy damp climate. It gets driven once in a while, but sometimes not for a month at a time. The interior used to get mildew on the cloth seats in the winter until I bought one of those marine fans and put it inside. I keep it plugged in all the time and it never gets mildew inside now. The cord just goes out under the door with no problem. It's a much smaller space than a bedroom, but I would think two of them might be effective. They are silent and draw very little electricity. MIne has been running almost continually for maybe 4 years with no problems at all.