Insulation req for winter? & how big your heater/btus?

[nearhomeless]

I'm looking seriously at living out of a school bus "four seasons" style and am trying to figure out some way to minimize the fuel needed for heating, if not immediately, then at least after the first year. (I might have to make do at first) I'm in Minnesota and it gets cold here. Has anyone had any success in adding insulation and how much did that change your needs for heat? I would think it hard to put more than an inch or two of styrofoam and wonder if it's even worth it, and other methods being much thicker and impacting liveable space more than i'd like.

And with or without insulation what size heaters did you need to stay warm in various types of weather? Did you burn cords of wood or hundreds of lbs of propane or what? I'm trying to figure out what it will actually 'cost' to stay warm to figure out how much propane I have to get if I only go into town 1-2x per month for instance (and lack a large residential tank), and what the cost is vs going with other types of heat.

[paul iossi]

the highest r value insulation is cheap in the long run, probably a thincoat of spray foam to seal everything and then go from there.
if you're going to be stationary for the winter talk to the propane company about a 500gal pig and their fill service.

hint; if you put your location with your header info, it's easier for members to relate pertinent information such as used parts and climate advice.

[nearhomeless]

Cant head south. My dad is in a nursing home and I have to be within range to deal with his needs, even if i'm near-homeless myself. So have to stay here.

[SeanF]

1. Metal is great at conducting heat/cold, and the exterior metal skin and interior metal skin are connected with...metal. So even if there is insulation between the metal skins, it doesn't do much. If you leave the interior metal skin in place, consider that when the heated air in the bus comes in contact with the cold metal skin, the heated air will drop its moisture onto that surface. Even moreso if you're heating with an unvented fossil-fuel-burning appliance....blue-flame heaters, catalytic heaters, etc....those add moisture to the air.

2. Heat travels three ways...convection (moving air), conduction (through solid materials), and radiation (like standing too close to a campfire). Loss of heat through conduction will be a big enemy, since a school bus is a big steel tube. You need to stop the heat in your air from escaping via the steel structure.

3. School bus windows are notoriously drafty (loss via convection), so at the very least most of them should be skinned over, even better, removed and replaced with insulation & then skinned over. The front area of the bus will be a major heat sink... it is difficult to insulate properly, and there's a lot of glass (no insulation value). Think about a heavy blanket to block off the front, or a real framed-in wall with insulation.

4. You will lose a lot of heat through the floor (made worse by the fact that the heated air in your bus will want to hover up at the ceiling). If possible, consider blocking off the under side with straw bales or some other method to stop air movement. It is also possible to insulate the floor from the outside...I think some here have done it.

You can go bananas with insulation, but at the end of the day, it is difficult to get a bus well-insulated. Some here have spent REAL winters in their buses....hopefully they will chime in. It is said that you can't have too much insulation, and to an extent that is true. But if you mega-insulate the bus and still have the stock windows in place, all of the insulation will be for nothing.

Lastly, consider that different fuels have given BTUs per unit. Depending on your location & situation, it may be cheaper to heat with one fuel over another. Here's a link that shows BTU contents for different fuels, even for different wood species, types of coal, oils and gases.

Ugh, I'm rambling.
Good luck with everything, hope this helps
Sean

[SeanF]

The outer & inner layers of the insulation sandwich are foil-faced, cotton-based insulation:
http://www.bondedlogic.com/insulator.htm

The inner "meat" was R-Tech rigid EPS:
http://www.insulfoam.com/

The links have specs/r-value info.

Those insulations are relatively benign (as far as insulation goes) with their content and manufacture, and they made (IIRC) in Arizona. So I was sorta buying locally-made products.

The bus is fine in cold weather, but I don't deal with "real" winter, so who knows for sure. If I were planning on spending winter in the north country, I would (or would have):
1. Walled off the front/driver's area. Currently there is a heavy quilt that blocks off the front when heating or cooling. A real, framed-out wall with insulation would have better insulating properties.
3. More insulation for the floor, and/or radiant tubing within the floor.
4. Bigger propane heater, bigger or more tanks for same. Or a big woodstove.
5. Double-pane windows, possibly.

Or I would not do a bus at all, and start with a box truck instead. Much easier to insulate due to flat surfaces and right angles, the driver's area is already separate, and the box construction is fiberglass, which as far as insulation goes, has a few advantages over a steel skin.

When it comes to insulation, more is better; the R-values of any insulation are simply added together when there is a sandwich. Wood, glass, steel, air gaps within walls...everything has an R-value. (Google provides.)

But the interior cannot be air-tight, since regular air changes are necessary to stay healthy (and alive). But do make it as airtight as possible, and then control air flow/air-changes with fans & vents. I also think a vapor barrier is key, especially if heating with a non-vented propane combustion appliance (since the combustion of any petroleum product produces H20).

Yes, making the deck a monolithic thing to serve as additional roof insulation is not a bad idea at all.

As far as rollover safety...I can't really say how much was lost when the interior metal panels were removed. The first two panels over the driver's area are still in place...so that MAY help in such an event. I would guess it's not as strong as a stock school bus, but still stronger than a typical store-bought RV. I'm OK with it, but I also never carry passengers.

Sean

[SeanF]

Hey I thought of doing radiant floor tubing too! You could run it past your wood stove for night time and bad weather, and a solar water heating device for daytime use. My dad has just built a house with radiant underfloor heating and I've been trying to think of was that it could be incorporated into a bus. Another major advantage is if you actually use your clear water as the heat transfer liquid, then you have a dual-use system and can maybe save some energy/fuel on water heating when in a cold enough area to want to be running your heating system constantly.

Any other thoughts on this?

I haven't given much thought to in-floor radiant heating. But if & when I build another home - on wheels or otherwise - it will be a consideration.

Thanks for the insulation details. What sort of temperatures have you experienced? Below freezing? I think I remember seeing a picture of your bus covered in snow... how cold roughly were those conditions and how comfortable were you?

Coldest overnight outside temp ever was 12 degrees F(!) in Why, Arizona not far from the Mexico border. The charcoal heater was going nearly full blast and had to be restoked often through the night. At some point I let it go out and the temperature inside the bus went down to the low 40s. Which, considering everything, isn't so bad.

The usual coldest winter temps I've seen were daytime highs in the low 40s, lows around freezing/upper 20s. The charcoal heater was always enough to heat the bus; just had to have a fan going to move the air. Restoking the little heater every 4-6 hours was the only hassle, especially at night. Solution is a bigger stove with more capacity, or a propane heater (I did the latter).

[SeanF]

Originally Posted by joshoisasleep

Cool this is really good info. So walling off the front drivers compartment, better insulating the floor... any other "weak spots" you would imagine you bus has after those two?

Windows probably present the next largest heat loss. One problem with the standard household curtains/curtain rod is that they leave a gap of a few inches between the curtain and the window. This allows warm air to enter that gap, which cools and descends, bringing in more warm air, which cools and descends...creating a loop. So IMO it's important to have either curtains that are flush with the window, or for "real" cold, maybe even foam pieces to go over the window opening, or into the opening if they are recessed at all.

Other than that, keep all of your water plumbing within the heated/insulated envelope of the bus. I think there is a temperature at which propane will no longer flow (or flow happily) so that may be a consideration as well.

[nearhomeless]

Thanks Smitty, actually yes that looks like useful information.

That's one reason i'm planning on not really running much in the way of piping or wanting to use flexible tanks or direct feed from and draining to portable tanks and other workarounds, I want something that can safely freeze without busting pipes or which if something does bust it's so cheap it's no big deal.

Mostly I was looking for personal experiences of people who camped below freezing, what their heater size was, and how quickly they went through 20lb propane fillings to get some rule of thumb.