Staying Warm While Living in a Tin Can/keeping Kathleen warm this winter

On my other thread about getting a permit for a PSP house, Dale suggested starting a new topic about keeping warm during the winter while living in a travel trailer (or other tin housing, such as a vehicle).  It looks like my daughter and I will be living in a 28' 5th wheel trailer (it's a 1989, so not terribly old) this winter, in Eastern Oregon, which can get pretty chilly.  It's parked for now on my mother and step-father's twenty acres of pine trees, close enough to their pump house to run an electrical cord, and, in warm enough weather, to have the trailer hooked up to a hose.  In freezing weather, though, I'll have to haul water in jugs, probably from the pump house.  I was planning on using a sawdust toilet, but it sounds like my step-father has figured out a way for us to be able to come in their house freely and use the second bathroom -- it has a door to the utility room, which has an outside door.  We'll also use their washer and dryer. 

We will definitely skirt the trailer with some kind of insulation.  I'm thinking straw bales or old hay, as those would be easier to come by than bags of leaves, but I'll check with my friends in town and see if they have any leaves we can have (I've gotten leaves from them before for our garden).  We'll have to enclose under the bedroom of the 5th wheel, and I want to have a doorway on that and use the space to store my tools that I'll need access to. 

There is an almost-new propane furnace in the trailer, but I'd rather not use it any more than I have to.  If it's possible to do it safely, I'd rather have a small rocket stove -- I was thinking about taking several buckets of our clay soil up there to use in the construction.  But it will have to be SAFE.  I got a carbon monoxide detector yesterday, and will also get a smoke detector, but still!  Safety first, when it comes to wood stoves in travel trailers!!!

Okay -- backing up, Dale asked for some details. 

Yes, the trailer will be staying in one place all winter.  It came with the part of the hitch that bolts into the pickup bed, but not the plate for under the bed (that had been welded into the seller's pickup, which was totaled when the transmission seized up as they were towing the trailer down the road!  The trailer has a couple of dents in it, but no serious damage) -- I couldn't find anyone willing to install the old hitch!!  So a friend's husband towed it for us, and if we ever move it again, we'll either have to ask someone to tow it for us, or pay $600 or so to get a hitch installed in my pickup!

There is a soft spot in the trailer floor, so I'm going to put plywood down on the whole floor.  I was thinking about putting half an inch to an inch of insulation down under the plywood, but don't know if I'll be able to afford to buy that before I need to do the work (I've already got the plywood).  I hate carpet, so plan to just stain and polyurethane the plywood (already have the stain and poly from another project) and have a wood floor. 

We also plan to get a big tarp and cover the trailer for the winter, maybe stretching the tarp out to the sides sort of like a porch so we have a bit of snow-free ground to use.  I was thinking about piling straw up there under the tarp, both for insulation and to make a bit of slope to the roof in the hopes of helping snow slide off. 

We don't need to keep the trailer really warm -- I prefer temperatures in the sixties to sweltering hot!  And at night I don't care if it gets down to freezing, except that I don't want our canned food (and a couple of house plants we'll be keeping) to freeze up.  We have plenty of warm blankets, and have lived quite a few years in the Interior of Alaska in cabins with no electricity or running water, and a barrel stove for heat. 

My daughter is mentally handicapped (autistic and mentally retarded), with some health issues as well.  She has several auto-immune conditions:  celiac disease; vitiligo (loss of pigment in patches of skin); and lupus, or something close to it.  She functions on the level of a three-year-old (she's actually 31 years old now), although thankfully she doesn't need as much watching as a three-year-old would need.  Other than that, we are both in pretty fair shape physically. 

Back to the trailer, I have some clear plastic that I bought last winter to put over some of the windows here in the house, and didn't get to it what with Grandma having a heart attack and then dying.  By the time things settled down again, it was almost spring and no point in putting plastic over the windows.  So I though I'd put some of that over the trailer windows, and maybe also the roof vents.    We probably won't be running any water in the trailer so won't have to worry about plumbing freezing up.  Hopefully I can disconnect the kitchen sink drain to have it empty directly into a bucket, which will be emptied by hand.  (I've lived with that kind of set-up before -- just have to remember to check the bucket under the sink before each use!)

Dale, have at it with your ideas, even if they aren't so pretty!  (Although, I probably will try to pretty them up if it's possible -- it's hard on the morale to be living in a place that's ugly.  I've got to put new fabric on the horribly dingy cushions in the dinette, and make some curtains for the windows, and do some painting, and make the place as cute as possible, or spending a whole winter or longer in it will make me horribly depressed.  It's just one of those woman things, I guess!)

Kathleen

  Dale here.

    Hello Kathleen. It's getting pretty late so I won't finish this tonight. Just letting you know that I'm onto it. No research to be done because all of this is in my head so I'll have a snooze and then get going.

Been there done that... but my 5 year old son (now 25) is not HC. I do have an autistic son now (12) though... Anyway, I don't know how cold it gets there. We just used the propane. I spent $30 to $40 a month to heat, fridge, cook and have hot water.... all propane. Same size and style RV, my son in the part over the hitch and the "living room" was my room. The water heater was an "on demand" and I modified a timer thermostat to work on 12 volts DC. I also had a truck camper (unheated) that my son used as his play room. I didn't do anything to it at all and we were comfortable. Just about anything you have planed will help. I think if you are putting hay on the roof under plastic (I might use Tyvec over polytarp) I would cover as much of the roof as I could if it will take the weight. I have heard that doubling the roof insulation is as good as closing up a 6foot hole in the wall... might be lighter to put a bale at either end (maybe one in the middle) to hold up a 2x4 ridge. then use fiberglass or better yet Roxul insulation to cover the rest. The Roxul is supposed to handle getting wet better than fiberglass and not be as hard on the hands, lungs, etc. It does cost a little more though... I just got some because it will take the high heat in my RMH... and I will use it to redo my kitchen oven as well. As you only have 15A power... if you want to cook with it at all I would suggest an induction cook top. No fumes, but fast like gas and most are max 1400watts... leaving some left over out of that 1800watts 15amp will allow.

I'm not experienced with how cold winter gets in some parts of the world, would it be possible to insulate the hose running from the pump house?

maybe some of those straw bales you're going to use around the sides of the trailer?

As far as climate, we are in the high desert -- the record low for this area is twenty-five degrees below zero, F.  Hopefully it won't get that cold this winter, but the potential is there.  It probably wouldn't last too long, though.  The coldest it's been since we've lived here, about eight years now, is twelve below zero, and it was only below zero at night for a few nights.  Average winter night lows run in the single digits to the teens. 

I don't know how much sun will hit the trailer during the winter.  I'll get up there on Tuesday to put the plywood floor down and do some cleaning, and will see if we can figure out how much winter sun we'll get.  They have a lot of pine trees on their property, and there's a hill to the south of their house.  It's not really high, but the house is right at the foot of the hill, and my step-father has been regretting locating it there, as it doesn't get much sun in the winter.  So hopefully he thought of that when he positioned the trailer! 

Thanks for the tips so far!  I will have to come back and re-read them more thoroughly when I have more time -- right now my daughter is waiting (impatiently) for her bath, and I have to finish cleaning the house as there are some more people coming this afternoon after church to look at the house.  Been too busy this week to even think about cleaning!!

Kathleen

I can't emphasize strongly enough the importance of adequate clothing.  Wool or silk clothing (you can sometimes find wool and silk clothing at Goodwill or other thrift stores near wealthy neighborhoods) or modern thermal clothing ($$ ). Long johns.  Stocking caps.  Gloves or mittens.  You might also consider purchasing good-quality thermal sleeping bags for each member of the family if you can afford them, they are just a good emergency supply to have in case you're unable to keep the space heated for some reason (illness, power failure, etc).   

For most of humankind's time on the planet in cold climates folks didn't heat the living space.  Fires were for cooking or heating the people sitting near the fire.  Folks wore a lot of clothing even indoors and slept in beds that were either in a cupboard or had thick curtains.  We may need to emulate these old-timey ways again.

    I'm back.  Dale here.

  I see that you had quite a bit of input, much of which will be helpful.  Remember we talked about putting this in the frugality section?  I had planned on writing one of my giant editorial style tips concerning outdoor living and nomadic living complete with funny anecdotes and horror stories . But since we started ....

    The straw bales on the roof are exactly what I had in mind when I suggested you to get some. They should be stacked only one layer deep and then you can put a small amount of loose straw along the peak to give it some slope . You don't want to put too much weight up there. If the roof is very weak it might be wise to only use loose straw which is fluffed up.

  I'm going to assume that you are dealing primarily with dry cold which is good. This is much easier to deal with than if you were being rained on all winter. If there is an adequate supply of inexpensive straw, I would suggest opening plenty of bales and jamming lots of the material under the trailer. Hopefully it has been sited so that water doesn't accumulate but even if there is a little accumulation  this will still keep the floor warm although it would eventually rot out the trailer. These things don't have much inherent value so your main issue is not freezing this season. A plastic vapor barrier, laid along the ground would prevent the straw from wicking moisture from damp ground. If bales are cheap and abundant you could stack them around the whole unit up to the bottom of the Windows. This assumes that your tarp would keep them dry. I think the whole thing would look much like the way they set up bales when selling Halloween pumpkins.

    Vermin will always seek out warm places in the winter and you will need to place lots of traps. Cats might help in this regard.

  Regarding your heating system.    If you're putting a big tarp over everything, it's absolutely vital that you make sure the propane chimney can vent to the outdoors beyond the tarp. If there are separate chimneys for your stove and heating system both need proper ventilation. I like the idea of heating this thing electrically.

    Remember what Ludi said about heating the people? There are several types of electric heater, some of them heat the air and allow it to immediately rise up towards the ceiling.  Baseboard heaters do this and they are a very poor choice for your situation. You want the type that radiates or shines on to your body. This feels just like sitting in front of a fireplace. In many trailer situations there is huge temperature stratification. Someone on a top bunk may be quite warm while the person sitting at the kitchen table has cold feet. The radiant heater reduces this problem. Good units have numerous temperature settings and they have automatic shut off safety switches so that if it is tipped over it shuts down. Don't get an old heater that doesn't have this feature since it's quite likely that you or your daughter will knock the heater over occasionally.

    Ventilation is absolutely vital particularly when it's damp outside. The big tarp will interfere with your ventilation so you'll need to throw the doors open and open the Windows occasionally to allow moisture to flow out.  If you get your hands on some cheap wool blankets they could be hung along walls and over  unused Windows. Not only will these add to your insulation value, they will also absorb plenty of unwanted moisture. If you had 100 pounds of these, they could absorb about 35 pounds of water and still not feel wet. If they're placed on hooks and easily removable they could be taken outside and dried occasionally. Even in cold winter weather they will  lose lots of moisture if the relative humidity is low. Alternatively the blankets could dry in your mother's house. Many homes lack  moisture in the winter so there's a possibility that they could just be hung rather than put in the dryer.  The moisture in your home comes from two primary sources. People breathe out moisture and the propane stove produces lots of water vapor when in use. Therefore, the best time to ventilate is when you're cooking. But I think with electric heat which tends to dry things out you may be just fine.

    If you're able to do the underfloor straw thing there'll be no need to use carpet underlay. I only suggested that in the other thread because I thought you might be mobile.

    Good night and good luck.  Dale

   I know that you're keen to build a rocket stove as are half the people on this forum. But given that you have available electricity and the two of you are trying to squeeze into a trailer, this might not be the best time for that.

   Here's a simple way for you to have some thermal mass so that you can sleep with the heat off but still have some residual heat. Get some used firebricks and stack them directly over top of whatever stove burner you use least. While you're cooking and ventilating you could also have this burner on low and the bricks will heat up. If the heat isn't needed immediately and the bricks aren't too hot they could be covered with a towel to save the heat until later.

   If you absolutely have to have a rocket mass heater I would build it small and portable, probably a gravel filled unit as pictured on one of the YouTube videos. You'd want to put concrete blocks or some other shoring under the floor if you're putting anything very heavy in a trailer. Again, I wouldn't build a rocket stove just yet.

I was kind of thinking the same thing about the rocket stove, at least for now.  I do think I'll keep looking for the parts needed to build one, just in case it becomes necessary, though.  The place where I was thinking about putting it would be better used with a chest of drawers there.

Ludi, thank you for the advice on warm dressing -- we do pretty well at that, having, as I've mentioned already, lived in Alaska in small cabins for quite a few years.  I've even worn a balaclava to bed at times!  We don't have silk long underwear, but do have some long underwear that's pretty adequate.  We each have a couple pair of boots that are good for the Interior of Alaska so should deal with anything we are likely to ever see here, and if our feet start getting cold, we do wear those inside the house. 

We will both sleep in the 'upstairs' bedroom, so I can be sure that my daughter is staying warm enough (she has a tendency to kick her covers off).  Tuesday when I go up there to work on it, I'm going to toss the dirty old mattress and examine the bed platform -- I'd like to put both our twin mattresses in there, with a shortened bookcase between them for a little bit of privacy and extra storage.  But if that won't work, I'll figure out something else. 

I just mentioned the 'straw on the roof' idea to my mother -- she thinks it's a good plan, but wonders if the roof would be strong enough to hold bales?  We could put flakes up there instead. 

Kathleen

Bubblewrap window blinds may have already been mentioned somewhere:  http://mtbest.net/bubble_glazing.html

I plan to do this on our bedroom windows, because they are horrible.

plastic wrap or bubble wrap all the windows because they will be leaky

if it has a roof style AC cover that throughly I like to use the big rolls of shrink wrap

skirting that keeps the wind from getting under the floors is vital both because it will reduce your heating bill and it will help keep pipes from freezing

if you are parked in a place with good electric service electric heat can be better than propane particularly if the propane heat is not vented (unvented heaters release a lot of water vapor)

A blanket hung like a tapestry over the door can reduce drafts

careful with flames in there trailers burn fast if they catch

resting the weight on cement pads (can just be blocks) or lumber and taking the wheels off makes it less scary on a windy night

and just in case I recommend buying a t least four trailer anchors and tying the thing down not that sever weather is real likely here on the wet side but its relatively cheap insurance

My step-father doesn't want me to use electric heat, although I do have one of those little oil-filled heaters that I could use temporarily if for some reason the propane heater quit working (it's nearly new, so hopefully it won't give us any problems).  In fact, I'm going to offer him a hundred dollars a month towards the electric bill, even though I'm sure we won't use anywhere near that much, if he'll just turn THEIR heat up enough that my mother isn't freezing all the time!  I'm sure the propane heater is vented, so hopefully we won't have to worry about excessive moisture, but it's so dry here most of the time that extra moisture indoors can be a good thing.

My step-father used to deliver and set-up mobile homes, and he set the trailer up on cement blocks, but I don't know if the tires are still resting on the ground -- or at least he set the jack legs on blocks.  I haven't seen it since it got moved to their place, so am not exactly sure what he did.  Anyway, I'm sure he's made it stable. 

We often get high winds here at the house, but their place is much more sheltered, between trees and hills.  I don't know if the trailer will need to be tied down there or not, but will ask my step-father what he thinks.  If it was here, I'm sure tie-downs would be a very good idea.

Bubble wrap and a blanket over the door are both excellent ideas, too.  And we will definitely be skirting with something, even if only straw bales. 

I think we are going to be pretty comfortable this winter, actually!

Mom did some looking at the trailer today, and discovered that the sofa I wanted to take out to make room for my sewing machine has got a water tank and some other stuff underneath it, so I guess it will have to stay.  I'll have to figure out some other way to have the sewing machine in there -- it's a bit difficult, because you can't just set a treadle machine on top of a table!  Also, it's four feet wide when the top cover is flipped down for more work space (and the cover has to be flipped down in order to get the sewing head up out of it's storage compartment).  I'll have to do some measuring Tuesday while I'm up there.  If I get rid of the sofa cushions, though, maybe I can put my sewing supplies storage unit and another storage unit that I need on top of the sofa platform!  It's going to be interesting, anyway!

Kathleen

Fill that water tank its a nice size thermal mass

Brice Moss wrote:
Fill that water tank its a nice size thermal mass

Good thought!!

Thanks!

Kathleen

This may not be acceptable for some but  different strokes..

There is a whole LOT of styrofoam  tossed into landfill. I have been collecting the boxes used to ship live fish, lobsters etc. in  and have lined one room with the lids (top side facing into room so the cavities make a dead(ish) air space. Even the floor where possible. It reflects light like crazy! and it's warm to step on after the floor outside the room, although the room is unheated.. The area where the door swings is a bit problematic and I am just using the thin white sheets that often come with apple boxes to cushion the apples when boxes are stacked one on the other. It's all put up with pieces of double sided (carpet) tape.

I am setting it up as a greenhouse and the inch or so thick insulation should mean that since it's a small room (used to be a bathroom) I am hoping that a crockpot filled with water and left on will keep it warm enough through the night and other times the wood stove isn't on. The plants will go right into the boxes, which should also help to keep them snug. Some boxes have been cut and used to line the walls. Haven't been able to figure out how to do this without making a mess. 

If this eventually gets extended out into the rest of the house then I will likely cover the styro with some sheets or something, but the light it reflects is helpful for a grow room.  It can be painted too, but some paints will melt it. I think most latexes are fine. That might be a fun thing to do. I used to try to think of things to do with the packing that came with TVs and things and always thought you could make some funky art  with them.

I know that if it catches fire it is entirely evil.  If it catches fire then I will have other things to worry about.  I'm not worried about outgassing. The stuff in the room is all food grade, I also have a bunch of styro recycled from gift shops (all that fragile stuff gets packed in it) that's getting stuffed into bags and put in the crawl space or perhaps even in the attic. It's light enough that I can handle it, and packed in there enough that it should help a lot even if it is full of airspaces.  Big sheets get used and fitted together like jigsaw puzzles.

There are likely other places with an abundance of this stuff they are tossing away which can be repurposed..I even snagged some sheets from a lumber yard that were about 4 feet by 3 feet that they were tossing out as it was just packaging.

When I'm done with this place then it can all go to the landfill if needed and nothing lost as it was all headed there to start out with.

Anyway, it was just a thought I wanted to share in case it might be of use. It's not fun being cold.

Pam wrote:

I am setting it up as a greenhouse and the inch or so thick insulation should mean that since it's a small room (used to be a bathroom) I am hoping that a crockpot filled with water and left on will keep it warm enough through the night and other times the wood stove isn't on.

I guess it depends on how cold it is outside... But the 1Kw baseboard in our Bedroom (180 sqft) ended up wired 120v instead of 240v. This means it was only using 250w to heat our room... which it still managed to do... it was "on" a lot more than a 1kw would normally be though   anyway, our crock pot is 200W, if your's is similar it should have no problem heating a bathroom sized room.... In fact, I would put a baseboard style thermostat (they are cheap new or free used... the box to put it in costs more)  in line (middle of an extension cord works great) to make sure it doesn't get too hot. In general I have found most portable heaters are too powerful. I look for the smaller ones (power wise) and run them on low.... sometimes I disable the high setting so I don't have finger trouble... I have found that 400W is all I have ever needed. This is what the 5 fin oil filled heaters do on the lowest setting (400/600/1000W). If there is a 7fin model, (600/1000/1400 I think) it can be modified down to 400 by cutting out one of the fins wires on the 600w circuit. (each fin is 200w) In fact a 7 fin model could be reassembled into 3 heaters....  but I would rather leave them as the extra fins not being used act as mass to smooth out the heating cycles. But where space is consideration, a two fin (or three) heater could easily be made.... In fact the two fins could be mounted on the wall flat. to save even more space.

Note, this would void the warranty .... 

  Your stepfathers concerns may simply be about the price of electricity. So, you agree to pay any increase in their bill. Alternatively, you could log the number of hours you're using the heater. A 1000 W heater consumes  1 kWh of electricity every hour. Thus the name. . A 500 W heater uses 1/2 kW per hour and a 1500 W heater uses 1.5 kW per hour. Grade 2 math.

  Now you just need to know how much they're paying per kilowatt.

If you are running the whole camper through  standard outlet instead of an RV (30 amp) you need to be careful to keep the total load on that cord/outlet under about 1500w note that one standard space heater draws that much. Your stepdad may be opposed to electric heat because too much load would create a fire hazard in the house end.

A thought that comes to mind is that if you can make some sort of enclosed porch area for a sort of airlock so the wind doesn't whip into the house every time you open the door that would help a lot.

Someone on another thread somewhere said that they could get 8 foot pallets from a car dealership. If so, you seem handy enough that it would be a relatively simple matter to make something of the sort.

Pallets can translate into nifty little places like this http://www.instructables.com/id/Pallet-Playhouse/   (though that one isn't typical)..the tiny house guy has a series of posts on building with pallets starting with this one.
http://www.tinypallethouse.com/2008/08/build-the-shipping-pallet-floor/   Although his orientation is to building on trailer decks, it usually isn't too difficult to level an area for such a project.

My only suggestions; if you decide to give this a go  try very hard to get 1) same size and style  pallets and 2) if there are lots, then select out the good ones and don't bother with the ones with broken bits and 3) avoid the ones made out of hard wood. Those are almost impossible to nail or screw and take ages to do anything with. Everywhere I've been there are lots that clearly have only been used once, those are the ones I aim for. It's a lot nicer dealing with what is basically new wood.  The ones that are painted  are likely ones that the business  will be returning to their supplier for recycling as they are charged for them and you don't want them anyway.

I've never been lucky enough to find 8 ft pallets but maybe haven't been looking in the right places! They would make life easy. You could fit one smaller one to allow for a recycled window...Stuff them with straw clay...or even just straw since it's a bit late in the season to be messing about with clay slurry.. and tack a plastic tarp over to keep everything dry and windproofed.....

btw you can get free tarps from lumber yards..the lumber is shipped wrapped in them and all the lumber yards seem to throw them away. Some will have pinholes, most,  rips and tears..the guys are seldom careful about unwrapping the lumber since the tarps are on their way to the dump but sometimes they will help get one or two off with a minimum of damage. I've never got one that hasn't had a lot of usable tarp. If the pieces are long enough you can fold them over so only the solid coloured underside shows  and the printed part is on the inside so you aren't splattering advertising all over your house.

Brice Moss wrote:
If you are running the whole camper through   standard outlet instead of an RV (30 amp) you need to be careful to keep the total load on that cord/outlet under about 1500w note that one standard space heater draws that much. Your stepdad may be opposed to electric heat because too much load would create a fire hazard in the house end.

Always look for a space heater with a low setting. 1500/750 is common (1400/700 in Canada) or 1400/1000/600... I like the 1000/600/400 ones though as I have yet to have a room require more than 400w. With 400w a microwave (up to 1000w) can be on the same circuit... not sure about a toaster.... and most toaster ovens are too much. Cooking with a crock pot is a great idea with only one circuit. Also remember this circuit is running the well pump as I recall. I would get grumpy if I had to reset a breaker every time someone flushed too. Starting current can be quite high on a pump.

Thank you all for the good information.  The space heater I have is one of the oil-filled ones, and it does have a low setting -- do you think it would be all right to use it?  I don't plan to rely on it, but we are planning to go back up there this Friday and Saturday to finish cleaning and getting the place liveable, and I haven't filled the propane tanks yet.  It's getting down into the teens and twenties at night, so we'll need at least a little bit of heat. 

Any ideas on taking out the existing sofa?  It's a hide-a-bed, with all the metal parts underneath -- I didn't take a flashlight with me yesterday, but it wasn't immediately obvious how to disconnect the thing and remove it. 

Making a 'front porch' is a very good idea, especially since the door is facing more or less north (I think it's actually facing NNE).  I won't be able to make anything very big, because they put the trailer right in between some trees and there's not a lot of space between the trailer and the trees, but I should be able to go out four feet or so. 

Kathleen

Kathleen Sanderson wrote:
Thank you all for the good information.  The space heater I have is one of the oil-filled ones, and it does have a low setting -- do you think it would be all right to use it?  I don't plan to rely on it, but we are planning to go back up there this Friday and Saturday to finish cleaning and getting the place liveable, and I haven't filled the propane tanks yet.  It's getting down into the teens and twenties at night, so we'll need at least a little bit of heat.

What size is the heater? I have seen three sizes, 5 fin and 7 fin (mid thigh high) and a short one (not sure how many fins). The tall ones are 200W per fin... so the 5 fin one does fins 2&4(400w), 1,3&5(600w) and all for 1000w. At 400w, there is 1400w (11.66A) left on a 15 amp breaker... The 7 fin ones are generally 600/1000/1400. The low setting leaves 1200w (10A) for whatever else. Remember, everything puts out heat that uses power, including people and animals (a dog would be helpful... I have read that lap dogs were bread to keep laps warm). Other things that will be drawing power besides the water pump might be a battery charger... propane heater probably runs on 12v.. mine did. Computer, phone(or it's charger) and sound. A two way switch such as the ones used to allow two switches to control the same light, could be used to force the heater off when using a kitchen appliance (microwave for example).

Just as an aside, even though there will be 12V lights that run off the battery, they will take more of the ac power to run than low watt ac lights plugged direct. Also, as I recall, all my 12v lamps were incandescent and led replacement bulbs may not exist for them. All of the battery run bits are taking power from ac too. If the battery circuit is designed just right (don't hold your breath), some of the intermittent use things will use more than the charger can supply dropping the ac required, but generally, it would be designed so that ac covers everything plus charging.

Should you ever get solar pv panels then use 12v dc over 120v ac.

Any ideas on taking out the existing sofa?  It's a hide-a-bed, with all the metal parts underneath -- I didn't take a flashlight with me yesterday, but it wasn't immediately obvious how to disconnect the thing and remove it. 

the one I have taken apart, just had 2 or 3 screws at either end. They are sprung, be careful, as they expect the weight of the mattress to counter act the springs. I think... take the mattress out, refold and tie together with chicken wire before removing screws is what worked for me. Go slow, look carefully, be safe.

Late to the party......but the single most effective thing I know about for making a RV more comfortable for long-term living and Winter use is attaching a shed to the door. It becomes a “mud room” where a wood stove can be used without messing up the RV. Boots, coats, firewood, etc can also be kept there. This also cures the moisture problem in the RV as the wood stove cooks out all moisture. Remember to drink enough water as it cooks the water out of the inhabitants also. But what a difference it makes over the crummy heater a RV comes with.
Some sort of rocket stove in the shed would be nice to reduce wood consumption. Long burn times are essential however as the RV is not insulated well and quickly cools down. A mass heater is usually not an option unless the RV is going to be stationary. Water as mass in a tank is an option as it is easily filled and drained. A tank under the RV and surrounded by straw bales might work good. Or a large bladder bag full of warm water under the RV. This could be rolled up for moving. Rodents might be a problem.