James Freyr wrote:Is the garage climate controlled in any way?
Mike Haasl wrote:I wouldn't pack the 8.5" insulation down into 5.5" of space. So of the two options, I'd go with the R15.
A third pain-in-the-ass option would be to get the R-25 and split it down into 2/3rds and 1/3rd. Then you can do three bays with two bays worth of insulation. IF it splits apart relatively evenly. And if you don't mind making a ton of fiberglass dust as you tear it.
Travis Johnson wrote:
But I would not bother to insulate at all if you are not going to heat it, now or in the future.
Eric Hanson wrote:
I don’t suppose there is any chance that you could put in a small rocket mass heater is there?
John Weiland wrote:This will be a longer 'observational' post from some metal garage/barn building on our property over the past couple of decades and will include some comparison with our house. (I hope this is not hijacking Trace's original intent of the thread and hope it generates further discussion.) The house is ~1915 built, so before electrical/plumbing/central heating, etc. I suspect houses like this were built a bit 'drafty' due to the use of a central woodstove (cookstove) and the need for air exchange,.....but it should be remembered that winters here hover a lot of time around 0 degrees F. The house has some sort of newspaper-type bits for insulation that they must have used at the time of construction. We are even draftier than normal due to reasons I won't go into, but the house would be considered a compromise between 'tight' insulation and open; we definitely are burning more wood and fuel oil than we need to.
We have several small outbuildings that were insulated to varying degrees with the whole gamut of what's available, from that silver 'bubble wrap' type insulation to hard foam sheets to fiberglass bats. Animal stock live in these buildings and their own heat is the main source, although we've added greenhouse attachments to the buildings which add A LOT of heat of sunny days. The buildings cool down at night, but the immediate animal quarters provide an extra separation from the cold.
We had two steel post and beam buildings erected over time....neither of them insulated and neither have anything but the initial gravel/sand flooring upon which the structures were built. We do have chickens that live in them and fare pretty well, but these buildings are cold.....you could not in any sustained way work out in them in the middle of winter without space heating. Part of the reason I've not gone whole hog with insulation on these buildings is the chewing rodent factor. Because we have the stock animals and have lots of food in various parts of these buildings.....again, for reasons I won't go into.....rodents *will* find whatever bits fall here and there and will make a home where there is food. The damage from mice and rats has been enough on the little insulation that exists in the smaller outbuildings to have been a deterrent to insulating these steel buildings until something permanent is done about mice/rats/.....and English sparrows (aka, "rats with wings"...!)
Here's a more interesting observation. After the collapse of our 40 X 80 ft. quonset this past spring from excessive snow-load, we used the same builder who did the steel buildings to build yet another structure, this time 30 X 40. It's built on a 4 ft high pad of gravel and fill (county code for flood zone)....the pad extends 10 to 15 ft beyond the building perimeter and at the same height as the floor of the building as part of the code. This time, my wife wanted a warm building and we settled on the probable toxic gick selection of spray foam insulation along with a ceiling that is insulated above it. There are many doors and windows in this building because we anticipated that moisture would be an issue.....and it has been, but not enough for us to regret the decision. This is the first winter for this new building and we've already had many days around zero degrees F and some nights down to -20F along with unseasonably cold days. What is striking is how warm that new building is. In all of the other buildings, we are well into the period where water bowls freeze rather quickly and need to be chipped out and replenished once per day, sometimes more frequently. But in this new building, the water has never yet frozen. I will add that I installed a 5000W electric garage heater in that building and my wife said she's had it turned on for a bit when preparing food, but only on the coldest day so far....it otherwise stays turned off.
So I guess I'm pleasantly amazed at how 'self-heating', for lack of a better term, this new building is. I can't say how much might be passive solar from the building itself just warming from the sun, but we are at the worst time of year for that to have a major effect. I'm left wondering about the size ratio of buildings and the amount of 'pad' or ground on which they are built---Could geothermal explain some of the heat in this building even though it was not built with any deliberate attempt to capture such energy? As it is a new building, we have not ruled out installing some sort of wood burner....RMH or other such item....although the installation of food storage bins and electrical wiring are the higher priority at the moment. For us and maybe for others with animals to feed, the uneaten feed that falls here and there or gets left in bowls is cause for bad rodent issues.....which leads to destroyed insulation. I'd be curious as to other's solutions to this problem and use it as a heads-up to Trace as something to consider if there will be food around garage after the new insulation. Thoughts?
John Weiland wrote:Trace, one more consideration of a 'tweener' variety....somewhere between a proper RMH and a standard woodburner, just in case you wish to experiment down the road. I'll bump this thread to get started (you may have to scroll to the top of the thread to see the build):
The design met with well-deserved criticism for lack of engineering detail, but it does function and was simple to install. It is still working and is still sitting, as a prototype, in a drafty, uninsulated building. I fire it up everytime I go out to do some little item in the shop there and only when the temperature outside is below 10 degrees F. (not unusual for me to be out in that building when it is -20 F). It is, as was noted by Peter vdB, essentially a batch-box rocket heater....not a rocket *mass* heater since there is no mass that it is heating. It is relatively compact since the horizontal exhaust portion is just long enough to get outside of the building before turning upward into the main exhaust chimney. (The chimney is now as high as the roof lip and the system does 'pull' better than before.) Part of the reason for reviving the thread was your comment about fast heating. Since my building here is uninsulated, it's not a fair comparison....I can only go with what the magnetic thermometer on the barrel reads. That said, when I fire it up with a good fire build (good dry kindling and/or cardboard scraps), the barrel will be at 800 - 900 degrees F within 10 min., often sooner than that. If I stoke the box with additional wood and adjust the door opening 'just so', it will hover between 400 and 600 degrees pretty steadily depending on the amount and quality of the wood still in the burn box.
The convenience of your torpedo propane unit is obvious and I certainly understand your reasons for wanting to go that route. But if you wish to dabble with the RMH concept in different forms, just thought I would add this here.
Travis and Mike, thanks for additional input on our insulated building....I will be monitoring the temperature throughout the winter. The south face of that building is shown below and we hope to add a long, maybe 8 - 10' wide sunroom addition on this side that will encompass the far walk-in door and the large garage door---that way on sunny days, we can open those doors and capture extra passive solar heat.
Eric Hanson wrote:Trace,
Yeah, ok, I get that the RMH in the garage is pretty far fetched. My thinking was that if you could heat some mass—as opposed to air—the mass alone could provide some heat that would not simply rush out the door every time it gets opened.
If you don’t mind me asking, where are you located? -30 is awfully cold, but I have been there as well. I grew up in central Illinois and we regularly got temperatures that sank to the -20 to -25 territory. I had a beloved outdoor cat growing up and one year he was sleeping in an old pet crate (used to transport medium sized dogs in a plane in the 1960s. Inside the crate we put a laundry basket lined with an old sleeping bag. We put an old blanket over the whole thing to give a sort-of door to the crate. But it was still probably -10 at the warmest inside the crate. My solution was to add 3 1-gallon jugs of water (they were old milk jugs) filled with hot tap water. We stuck these jugs just behind the laundry basket.
An hour later I went out to check on my cat. I pulled the blanket back, stuck my head in and was greeted by a blast of 90 degree air and my cat was purring loudly! The next morning the temperatures had dropped to “only” about 60 degrees. The hot water had more than held up all night.
My point in all of this is that a hot mass can really store heat a LOT better than air can. This is an important component of the RMH. I know that this is still likely far fetched, but is there any chance that you could heat a mass to leave inside the garage to slowly radiate away it’s heat?
This is really just me spitballing but I think that s heat radiating mass is great way to store heat. Water has an amazing heat capacity so some hot water is a 5 gallon bucket with lid attached would store and slowly release a generous amount of heat. I had neighbors (that sadly moved—I really liked them!) that had chickens outside their house in a little hutch. They were using the deep litter method to heat the chickens on cold nights (which around here is more like 10 degrees), but this technique was not really working. I told them about my cat and suggested the 5-gallon bucket of hot water with a lid and they were sold! They continued to use a 5-gallon bucket with a lid until they moved. Their chickens were happy!
Anyhow, another long winded post and take it for whatever you think it is worth.
Mike Haasl wrote:I guess I don't see how putting 1,328,994 BTUs* of heat into barrels each day and then letting it bleed out into the garage and out the door when it's open, would be a viable solution. You'd basically be heating the garage daily in case you need heat. And dealing with freezing and pumping and a lot of complication.
I'm thinking it's much better to just come up with a space heater that will quickly heat the space for those times when you need it. And maybe a bit of mass, or insulation, or an easy way to keep it burning through the night on -40 nights. Is your garage open to the roof decking? And do you have soffit vents that are open to the interior of the garage? If so, you have a continuous leak of air so the insulation may not do as much as it would in a "tight" building.
*made up number