| Author | Message | ||
| Bob Wood so cal (4.63.41.14) Rating: |
can anyone please tell me approx how long a 30 lb cylinder will last when using a 35K/BTUH propane furnace in near freezing weather? thanks in advance, bob | ||
| TWO DOGS (66.90.214.184) Rating: N/A |
20 gallons will last 'about' a week if you keep thermostat at 68 drgrees....kind of a 'how long is a piece of string' question....depends on LOTS ,insulation,air leaks,warmer in the daytime | ||
| Scott Whitney (66.82.9.37) Rating: N/A |
30Lbs is about 7Gal. Won't last long if your furnace has to run much. My 35KBTU, running at about 50% duty cycle, will suck down 20LB bottle in no time flat when it is really cold. But then again, I've got more insulation now than I did last winter, so we will see. But like 2Dogs sez, a lot of factors to consider: size of space you are heating, insulation value, thermostat setting, day time highs, shade or sun, color of coach etc. If you are going to be in sub-zero temps for very long, you may want to get a 100# cyl. and set it next to your coach. Saves a lot of trips to refill. Scott | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
thanks guys. my bus will be halfway decently insulated, i'd like to do the spray foam, but $ is kinda tight, so styrofoam with spray foam around it is probably how i will do it. bus is still empty, looking forward to the conversion part. getting her roadworthy now is where i'm at, filters and fluid changes, then gearing. all the best guys!!! bob | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
also, i don't plan to do much sub zero camping... but you never know! thanks again gentlemen. l8er, bob | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
You know Bob, I did the math on my bus, and the cheapo styrofoam isn't so cheap after you add it up. I'm not quite ready to insulate yet, but I think I'm going to pony up the dough to have mine sprayed. Gary | ||
| TWO DOGS (66.90.217.188) Rating: N/A |
I always go by gallons....easier for me...but 30 pounds ....a day...maybe two...I have 66 gallon tank in the Eagle...and ...am hopeing for a month.... | ||
| JC Barnett (12.220.190.142) Rating: N/A |
There is 96000 BTU's in a gallon of propane. If the 35000 BTU furnace burner stayed on for 1 hour it would use 1 gallon of propane. | ||
| Peter Broadribb (Madbrit) (216.67.210.100)
Rating: N/A |
Bob, Give the styrofoam a miss, not much R-value in that. Save a little money and use Tuff-R or one of the similar products of the Isocyanite foams from Dow or Atlas. You get around 6.2 R-value per inch and it costs $12.80 per 4x8 sheet. If you need it thicker, then its cheaper if you buy 1 1/2" or 2" thick rather than doubling up on the sheets. If money is tight, then start at the back and insulate the bed and bath areas and get them near completion as best you can, so you can use the bus, then as money comes, you can continue towards the front. Peter. | ||
| Sam Sperbeck (206.230.105.230) Rating: N/A |
Hi JC Barnett, You must be useing the new math they are teaching in school today. If one gallon of propane has 96,000 BTUs, how can a 35,000 BTU furnace use one gallon of propane in an hour? By the math I was taught 96,000 divided by 35,000 equals 2.74, or a 35,000 BTU furnace will burn for 2.74 hours on one gallon of propane. Did you leave out a conversion factor that I am not aware of? Thanks, Sam Sperbeck La Crescent, MN | ||
| Scott Whitney (66.82.9.31) Rating: N/A |
Also, remember that just cause the fuel has given up its heat value, does not mean that you enjoyed its warmth. A fair bit of heat goes out the exhaust to "heat the neighborhood". A furnace, with a heat exchanger, is less than 100% efficient. Wonder if someone could design a furnace/water heater that used the furnace exhaust heat to help heat domestic water. .. Scott | ||
| jmaxwell (66.81.44.183) Rating: N/A |
Thnks Sam, glad someone else took the same class as I. Perhaps he was factoring efficiency and such, which is actually somewhat indeterminate without instruments when it comes to rv furnaces, but nevertheless, has no relationship tothe basic gas consumption of the burner. I believe Dometic claims 85% burner efficiency and about 70% BTU delivery. As I recall I read these figures for the Suburban line. My experience with the Suburban line is that the actual BTU delivered output is on the order of 70% of the burner output, the 85% figure. So, what starts out as 35K ends up as approx. 21K delivered into the area being heated. The Hydroflame claims slightly better efficiency, but I don't know that to be a fact and note that in the high end S&S applications of Hydroflame they have installed 2 and sometimes 3 units to heat a 40' unit. | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
thanks evreryone for the info! i had not heard of the isocyanite foam boards, sounds like a winner. all the best! bob | ||
| Geoff (Geoff) (66.238.120.64)
Rating: N/A |
How much R-value do you need in a bus? When I was building my interior I had some 1/2" styrofoam glued to the rounded corners of my ceiling and I could touch it and feel no heat coming through when the hot summer sun was shinning on the outside (the bare metal next to the styrofoam would burn your hand). That is not to say I didn't put as much insulation as I could fill in the gaps, but sometimes I think we get carried away on trying to achieve the highest R-value when it isn't necessary. | ||
| mark (66.43.13.31) Rating: N/A |
Hey, Gary... How much did you figure it would cost to use the 'cheapo' styrofoam to insulate your 'bird? I think that it should cost MUCH less than the sprayed in stuff. Albeit, maybe not as much R value, but still very effective. I am using 2' x 8' x 1" styrofoam panels which I will 'foam' around to acheive the effect that I feel should be adequate for my needs. The panels are only $3 each. When doubleing them up for a two inch thickness, I figured that I could insulate the entire interior walls for around $100! (I'm going to settle for the orriginal roof insulation - not a full timer - just weekends and summers) Anyway, I think styrofoam is a viable option, especially if one uses spray foam to seal it in, and for a relatively low cost. I had reservations at first about using styrofoam, but then came accross the topic here on BNO a couple of months ago regarding this very thing. And yes, if I recall correctly, you yourself provided the information that I was looking for! (As to whether it was dangerous or toxic in the event of a fire etc.) Anyway, I've started with the insulation and it's working out great...and for very little $$ See Ya' mark 75 gillig 636D | ||
| Mallie (65.38.24.88)
Rating: N/A |
The short answer is about 13hours of total run time. Not for sure what you have but I would guess it is a 5 gallon fuel capacity. That is 30/ divided by 4.24pounds per gallon = 7 gallon times 80 percent capacity would be about 5. But what ever it is you can make it simple by knowing that you have 91,500BTU per gallon or 21,500BTU per pound. And realize that your 35k furnace probably only delivers 60 to 65 percent of the heat to your coach. | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
Our design requirements are pretty different. I need every smidgen of R-Value I can come up with, and then some. Our bird will see 115+ weather frequently, as well as sub-freezing (I work in Mexico and Michigan). i AM insulating the roof, it is probably much more important to me than the walls. Also, everything the birds are 26" on center. Which mean a LOT of wastage. I'm finding a different price than you have: http://www.lowes.com/lkn?action=productDetail&productId=15358-23946-15358 At $6.85/sheet Just using Square feet, I have about 650 square feet, a 4X8 Sheet has 32 sq feet, 650/32 = 20 sheets or so. Multiplied by 6.84 is like $140, except I am working with 2" so, more like $280. Then you factor in the wastage, you add say 30%, you end up at around 360. for about $100 more, I'm pretty sure I can have it professionally blown in, and it will be a better job. But again, it doesn't sound like your needs are as great as mine. I wish I could take the cheap route--But for around $500 for a good insulation job, it'll be worth it. Gary | ||
| TWO DOGS (66.90.218.141) Rating: N/A |
MALLIE 30 pounds was the initial question..or....I'm just too tired ... | ||
| Sam Sperbeck (206.230.105.230) Rating: N/A |
Hi Mallie, It seems we are getting some conflicting information in this thread. JC Barnett states that there are 96,000 BTU per gallon of propane and you say 91,500 BTU per gallon. Which is right? Also there are 30 # of propane in a 30 # propane tank so the 80% full factor doesn't enter into the equation when calculating the number of gallons in a 30 # tank. I agree with Scott that 30 # of propane will not last long in 40 degree or lower weather. Thanks, Sam Sperbeck La Crescent, MN | ||
| Mallie (65.38.24.88)
Rating: N/A |
Thanks Sam ,,You are right it is 7 gallons,, was thinking total capacity, water gallons. BTU can and will vary some in but very little. Technically 90k to 93k. 91,500 BTU per gallon is the figure we use in HVAC. http://www.patioheat.com/ApproximatePropertiesofLPGas.htm But what is a few btus,, 96k is close enough. And as been expressed in this thread, insulation begins to pay off quick if you are heating a bus in the very cold. | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
Gary- please tell me where you can get the insulation blown in for $500. i can't get the kit for much less than that. thanks! bob | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
One thing that may be being missed is the fact that Gary is talking about sub freezing temperatures and Bob about near freezing temperatures which cah easily change to sub freezing weather. At those temperatures, propane starts loosing its ability to change from a liquid state to a gas, and all of a sudden you may have no heating at all. I Believe in most northern areas, there is a mixture of propane and butane utilized, and I have no idea of what the btu properties of that mix is. I do know that it is not wise to come north with full propane bottles and expect to have heat at sub freezing temperatures. I do not believe I would even consider building a coach for operation in the northern winter climate without a diesel fired furnace. Electric heat only may not be sufficient as you may not have enough power available to provide the heat required to stay comfortable in freezing or sub freeing weather. However, I believe I would pick electric over propane, since you can run your genset 24/7 (if you do not have shore power) to generate electricity, and you would have a large fuel tank of diesel that would be relatively easy to get refilled in most areas without moving the bus. Richard | ||
| TWO DOGS (66.90.216.27) Rating: N/A |
BUTANE FREEZES....NO LONGER MADE...PROPANE O.K. | ||
| Mallie (65.38.24.98)
Rating: N/A |
Actually Richard Butane is the one that will quit flowing at 32 degrees. It also has over 100kbtu per gallon. Home tanks were buried. Propane has a boiling point of a minus 44degrees. Unless you are in very cold it will have sufficient pressure. | ||
| Sam Sperbeck (206.230.105.230) Rating: N/A |
Hi Mallie, Thanks for the clarification on the heat value of a gallon of propane and the link to the chart showing the properties of LP gas. That is way more information than I will ever remember but it is interesting to learn anyway. Thanks, Sam Sperbeck La Crescent,MN | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
"Gary- please tell me where you can get the insulation blown in for $500. i can't get the kit for much less than that. thanks! bob" By finding a local contractor that is on a job, and when I'm ready drive the bus, all prepped. over to the jobsite and getting it shot. It would take a little finagling, but I have a few contacts with local contractors, I bet I can geet it done in the $500 Neighborhood. Now, that being said, I follwed a link posted on BNO to: http://www.gumpydog.com/bus/index.htm Now, you all may be familiar with Craig's site. This guy is so meticulous, he makes me look like a hack. Craig, if you are a member of this list (Craig S?) I bow to your superior perfectionisim. In any case, he is using Polyisocyanurate insulation, the same basic stuff as the blown-in. I am actually thinking about changing my plan and going that way instead. Even a step futher, by installing a layer of reflectix in between the two layers of polyiso. I think this layup would even exceed the R-Value if blown-in, and the highest possible R-Value is my my goal. Gary | ||
| FAST FRED (63.234.20.127) Rating: N/A |
For severe winters an oil furnace is the only way to go. With 50 million homes heated with oil the Gov makes sure the price is as low as can be. Propane or other gasses have no such lobby and are stupidly waisted in making electric , so vary greatly in price and avilability. Oil furnaces can be complex nucances to maintain , but for loads of work you can make them sing. Would not be shipmate with one ,( again) but have seen them make domestic water , pre heat gen set or coach engine , co generate with noisemaker , and even heat towel racks . But most use a huge amount of electric for batteries to provide for many days. The furnace electric must be added to the fuel pump , circ pump , and frequently heat exchanger blower motors. Hurricane has fine marine units , but the lack of reliable electric during hard winter storms makes my choice a Dickinson oil fired range. No electric , start it in Oct & shut it off an May, with an oven hot all the time & a 4 burner cooking area warm all winter. Propane is great in RV noisemakers (gen sets) for cooking and absolutly great for a fridge. But for other than ocasional few weeks costs too much for all winter. MY Opinion only, FAST FRED | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
I'm planning to recycle the automotive-style heaters that came in my bird. I'm planning to use a webasto or similar diesel-fired boiler to keep the heater cores flowing with hot water. gary | ||
| TWO DOGS (66.90.210.43) Rating: N/A |
Fast Fred...sounds great...in yankee land....try to buy "heating oil" someplace else... | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Thanks for setting the record straight Mallie. I recall many years ago the problem was severe for those people travelling in motorhomes from Florida to Michigan. I even had troubles getting adequate heat in Motels in South Carolina if we had a real cold spell. I assume that butane is no longer supplied for this application. Richard | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
i will probably avoid the really cold weather as much as possible. i think the propane unit will be ok. sure would be nice to have a webasto! already have the fuel tank... oh well! all the best gents! bob | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
also, good idea on the "contractor on the job" angle, hadn't thought of that. wish i knew someone in that field. bob | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
Yeah, but here I am changing my story, talking about going with polyiso and Reflectix. That's OK, I guess I always have liked to execute a plan at the same time as I am making it. Gary | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
hey, as long as the plan gets executed. around here, we call that "on the job training". lately, all i do is plan. and plan. and plan. i want to get those tools back in my hands! i almost wish i could re- gut my bus, to have something to do... catcha later, bob | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
come on up to the bay area, I have a shop fulla tools and a skinless bus. Gary | ||
| Scott Whitney (66.82.9.13) Rating: N/A |
Come on over and help me! Got lots to do! How are you at cabinet making? : ^ ) Scott | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
Hey Scott, No fair. I beat you by six minutes. On a more serious note, I need a cabinetmaker too. Gary | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
hey, me too! i'm not too good at cabinetmaking. i did do a lot of the gutting though, no experience necessary for that! i plan to learn as i go, and to learn all i can. my carpenter buddy who is helping me with the conversion moved to AZ, (right down the street from my place up there)and i will be too fairly soon. if you lived closer i would come over and help you... at least help empty aluminum cans... hehe. sounds like we are all in the same boat guys! all the best, bob | ||
| jim mci-9 (209.240.205.60) Rating: N/A |
boat????? i got 1.. may need it later.... we've had over 8 inches of rain in the last 12 hrs.....gonnabe interesting.......... | ||
| Scott Whitney (66.82.9.38) Rating: N/A |
Hey Gary, That is weird, when I replied to the post no one had responded to Bob's "offer" yet. But I see your post did, indeed, beat mine. I must have dilly dallied on confirming the post. . . Scott | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
Yeah, that happens to me all the time, I was probably confirming, just as you were opening the thread. Gary | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
ya gotta be fast on the trigger round these here parts... hehe. catcha later guys, need me some shut eye. all the best, bob | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
ps. hey jim stay dry... | ||
| Peter Broadribb (Madbrit) (216.67.212.123)
Rating: N/A |
Gary, In reply to your Monday 11.59am post. Reflectix type insulation will only work with an air gap. Most of the packaging actually states this. I spoke with a dealer about Dow Tuff-R and Atlas and he said that it is cheaper to install in the thickest sheets you can get it in one go. For example, if you need 2" of insulation, using four 1/2" layers will be a lot more expensive than buying one 2" sheet. Also, he said that because you would have all those extra foil outer coverings, you would have a slightly better insulation than the single sheet. Not sure about that, but who am I to argue........ LOL. I am concerned about this commercial spray-in stuff as to whether the operators know how to do it. Apparently, if it is applied wrongly or they use the wrong product, it can have little or no R-value at all. Peter. | ||
| Bob Wood so cal (4.63.41.14) Rating: N/A |
don't laugh, i'm putting one of these pellet stoves in my new house... http://www.warmingtrendsstoves.com/parlourgnome_ps.html | ||
| FAST FRED (65.154.176.240) Rating: N/A |
Here in SW Florida my neighbors use oil for heating domestic water , and have no problem with home deliverys. The untaxed farm fuel is the same fuel , although a bit more expensive (its diesel fuel & filtered cleaner than house goop). Here the Propane is $1.75 a gal , untaxed died fuel $1.12, considering there are sooo many more BTU in the heavier oil its a bargan if loads of heat is needed 24/7. Simplest I have seen was a used house wet furnace outside the coach , hooked up with hose to a dual pass set of 1 inch heat pipes.Orig the owner had dual setup (ran down both sides of coach) but it was too warm . There was no way to get the "anticipator" in the thermostat set right. Removing one side & just having the water make a pass from the rear & back , thru the finned tubes worked well. CT doesn't get very cold seldom much below Zero, so the two pipe system might be better "up North". FAST FRED | ||
| Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A |
"Reflectix type insulation will only work with an air gap" I have used acres of reflectx, particularyly on my Cinder-Block house, where we furred out, used Reflectix and sheetrocked. In a normal situaton, you're right. I've actually had many arguments (Who Me?) with skoolie builders that wanted to glue the reflectix to the ceiling, and screw paneling over the top. I told them they were wasting money on the reflectix. In this case the reflectix would be a uniform "Spacer" between the layers of polyiso. I don't thing the foil back of the reflectix will conduct too much heat between the layers of Polyiso. http://www.dow.com/styrofoam/na/iso/tuff_r.htm Actually, this page doesn't exactly show any advantage to a double-thickness, actually in the "New R-Values" column it's less, but that might be a rounding error. The deal with the 2" stuff is it's VERY rigid. I have some pretty tight radiuses in my ceiling. My one negative on the blown-in stuff--I have to basically have 100% of the shell done in order to have it done. That's tough on the project schedule. I'm going to start costing out my "New" Idea and see what the cost is. Gary | ||
| Buswarrior (Buswarrior) (64.229.208.148)
Rating: N/A |
Hey FF! The Orion V transits at work, circa 1991, have radiant heat down both sides, and a heat exchanger in the rear mounted transit AC unit, ducted through up high behind the ad signs. Lots less maintenance than what the under floor fans and heat exchanger need due to crap sucked down through. Great warmth in those. I'm after some of the radiant heat radiator pipes for mine. Local bus heavy repair company has some pieces lying around. Only need the power for the Webasto burner and the circulation pump to stay warm. happy coaching! buswarrior |
