rody_44
Premium Member
join:2004-02-20
Quakertown, PA
3 edits |
to fartness
Re: Snow on roof as insulation? I wont be leaving it this way but this is the flame i get just by turning my damper fan off. Nothing wrong with it but im wasting money. You shouldnt be smelling anything tho. But being you have a insert. The question would have to be asked does your exhaust run up your whole chimney and than where is your intake ran from? The same chimney or the outside. The installers tend to install pellet stoves the way people want it with no relation to the most efficient way of operating a pellet stove. In otherwords you have adjustments and use them if you are smelling something. There should be zero smell with a pellet stove. Turn your damper up (if you have one) or pellet feed down. The goal with a pellet stove is the hottest flame with the lowest amount of pellets. With inserts and running the exhaust into chimneys often pellets stoves are not capable of running higher pellet feeds especially when running the exhaust up the whole chimney which if your running the intake from the chimney is most likely how they installed it. |
actions · 2015-Feb-25 12:02 pm · (locked) |
 robbin
Mod
join:2000-09-21
Leander, TX |
to 18189353
I believe H_T_R_N  is correct. The roof deck should not be involved in the insulation calculation of a house with properly ventilated attic space. Now a conditioned, unventilated, insulated attic space is totally different. 18189353 - Since you are stating that you disagree you are the one who should validate your position with facts. |
actions · 2015-Feb-25 12:04 pm · (locked) |
rody_44
Premium Member
join:2004-02-20
Quakertown, PA |
to fartness
I do construction for a living digging in the dirt. All Year the ground was frozen solid to about 18 to 24inches deep. Now we have 12 inches of snow on the ground. If i move that 12 inches of snow now tho the ground is thawed. Not sure how that works into what you guys are talking about but somehow i think you guys will get the point.
Edit, Didnt mean to apply to the op with this one. that snow will melt way before the ground would thaw without the snow on top of it. |
actions · 2015-Feb-25 12:37 pm · (locked) |
ARRIS BGW210-700
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to fartness
I think we can all agree at this point that snow is/can be an insulator. However, the point is that insulating a non-conditioned space has no/negligible effect on the insulation value of the conditioned space.
If you have a vented attic, the temperature in the attic should be the same as the outdoor temperature. Insulating the roof deck (snow, in this case) only serves to insulate a space that is already vented and open to outside air, and does nothing for the conditioned space below the attic. |
actions · 2015-Feb-25 12:50 pm · (locked) |
| |
to robbin
said by robbin:I believe H_T_R_N is correct. The roof deck should not be involved in the insulation calculation of a house with properly ventilated attic space. Now a conditioned, unventilated, insulated attic space is totally different.
18189353 - Since you are stating that you disagree you are the one who should validate your position with facts. I stated everyone else disagreed. Reading comprehension isn't up to snuff on these forums.  I miss the Mike Homes forums. |
actions · 2015-Feb-25 12:52 pm · (locked) |
 garys_2k
Premium Member
join:2004-05-07
Farmington, MI |
garys_2k
Premium Member
2015-Feb-25 1:36 pm
said by 18189353:I stated everyone else disagreed. I don't. A *PROPERLY* ventilated attic would always be very close to the outside air temperature. In that case the snow on the roof, or snow on the tree in the back yard, would have equal impact on the heat flow from the interior of the house to the properly ventilated attic. Now, if that attic is not properly ventilated, meaning that (in the winter) heat from the interior of the house causes the attic air temperature to be above the outside air temperature, then sure, snow on the roof would likely cause that attic air temperature to rise even more and reduce heat loss from the house's interior. |
actions · 2015-Feb-25 1:36 pm · (locked) |
 your moderator at work
 hidden : Off topic
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H_T_R_N (banned)
join:2011-12-06
Valencia, PA |
to 18189353
Re: Snow on roof as insulation?said by 18189353:said by H_T_R_N:Care to elaborate? I would love to hear how a properly functioning ventilation system in the attic space will allow the snow on the top of the roof to become involved in the insulation calculation of the conditioned space. I doubt you will respond with a serious answer, but I have to ask. said by 18189353:It's pretty simple really but very enjoyable to watch. Not sure simple is the word to use, sad is the word I'd use, but it is interesting to watch, I'll give you that. said by 18189353:I'm guessing it's so hard to make a simple point because it's invalid. Everyone else is either wrong or you are. It's pretty simple really but very enjoyable to watch. Did you just avoid the question or not see it? You need to validate your position with facts before anyone here will even engage you further. Take that anyway you want. Wait there was a question? There is this little thing called a '?' most people use when asking for a reply. » lmgtfy.com/?q=does+snow+ ··· ing+heatRead some, retain, and then come back. |
actions · 2015-Feb-25 2:11 pm · (locked) |
1 recommendation |
to garys_2k
said by garys_2k:said by 18189353:I stated everyone else disagreed. I don't. A *PROPERLY* ventilated attic would always be very close to the outside air temperature. In that case the snow on the roof, or snow on the tree in the back yard, would have equal impact on the heat flow from the interior of the house to the properly ventilated attic. Now, if that attic is not properly ventilated, meaning that (in the winter) heat from the interior of the house causes the attic air temperature to be above the outside air temperature, then sure, snow on the roof would likely cause that attic air temperature to rise even more and reduce heat loss from the house's interior. So by *PROPERLY* you mean fantasy? Even new houses built with spray foam insulation that are so tight they need make-up air brought in are getting ice dams this year. Is this a hypothetical discussion or is there some reality to it? Maybe I missed the fact it was purely hypothetical/fantasy. I apologize if that's the case. |
actions · 2015-Feb-25 2:35 pm · (locked) |
H_T_R_N (banned)
join:2011-12-06
Valencia, PA |
H_T_R_N (banned)
Member
2015-Feb-25 2:48 pm
said by 18189353:So by *PROPERLY* you mean fantasy? Even new houses built with spray foam insulation that are so tight they need make-up air brought in are getting ice dams this year. Is this a hypothetical discussion or is there some reality to it? Maybe I missed the fact it was purely hypothetical/fantasy. I apologize if that's the case. Do you have some reference for this ice damming in properly built homes? I can assure you my home and every one around here, save for a couple very old homes have a full coating of snow and have since the snow fell some couple months ago. Did you read any of the links google gave you? while some of them are not pertantiant some have some good info. |
actions · 2015-Feb-25 2:48 pm · (locked) |
Scilicet (banned)Spaced Out
join:2005-04-11
Aurora, CO |
to H_T_R_N
Yes, Yes, Yes and YES! Snow is 32 degrees. Insulation from anything colder. |
actions · 2015-Feb-25 2:48 pm · (locked) |
garys_2k
Premium Member
join:2004-05-07
Farmington, MI
3 recommendations |
to 18189353
said by 18189353:So by *PROPERLY* you mean fantasy? Even new houses built with spray foam insulation that are so tight they need make-up air brought in are getting ice dams this year. Not fantasy at all, my new 2014 house is having no ice dams, but in any case ice at the edges of the roof may have nothing to do with poor ventilation or high attic temperatures. I have ice in my gutters from solar induced snow melt on sunny days where the air temperature is still below freezing. Sunlit snow can melt from the additional radiant heat from the sun, the water naturally moves down hill and, while the sun is shining on it, runs off and soaks into the snow that fell there. When the sun moves to a different part of the sky, or sets, and no longer heats that area of the roof the water will freeze in place. Since the water has been moving downhill, and the snow pack there has been soaking it up turns into a solid mass of ice. Areas of the same roof, same house, where the sun doesn't get to (north faces) have NO ice at the gutters. It's strictly solar warming that is causing this ice. |
actions · 2015-Feb-25 3:13 pm · (locked) |
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lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
to robbin
said by robbin:I believe H_T_R_N is correct. The roof deck should not be involved in the insulation calculation of a house with properly ventilated attic space. Imagine a warehouse with R1000000000000000000000000000 insulated walls and floor, with no windows or doors. But it has a huge roof with only R10000000 insulation value and "properly ventilated attic" that you personally designed. Do you really believe that you can store huge pots of boiling witches brew inside that warehouse forever, with no heat loss through the ceiling/attic/roof? It is a rhetorical question.  |
actions · 2015-Feb-25 3:55 pm · (locked) |
1 recommendation |
Termites
Anon
2015-Feb-25 4:18 pm
Snow tells you alot about your home,have you noticed some of the Roof doesn't have snow?or its melted in spots... » www.energysvc.com/index. ··· sulation |
actions · 2015-Feb-25 4:18 pm · (locked) |
lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
to garys_2k
said by garys_2k:Areas of the same roof, same house, where the sun doesn't get to (north faces) have NO ice at the gutters. It's strictly solar warming that is causing this ice. Sensors placed right on the roof surface will occasionally detect moisture under the accumulated snow, even at night. Most of the time, the moisture is simply absorbed by the snow above. But under some conditions, the moisture will coalesce into larger water droplets, and eventually start flowing down the roof surface. |
actions · 2015-Feb-25 4:31 pm · (locked) |
garys_2k
Premium Member
join:2004-05-07
Farmington, MI |
garys_2k
Premium Member
2015-Feb-25 5:29 pm
said by lutful:Sensors placed right on the roof surface will occasionally detect moisture under the accumulated snow, even at night. Sorry, but that does not mean that the attic is being warmed by the insulated space below its floor. It only means that something melted the snow. If the attic is properly ventilated it will pick up very, very little temperature increase from the insulated house beneath it. Of course some heat will always move from the warmer side of the attic floor/house ceiling to the colder one, that's what heat does. But with enough ventilation to carry that heat (in the form of the boundary layer of warmed air, coupled to the insulated surface) away and replace it with fresh, unheated air from the outside the net temperature gain is very small. At equilibrium the bulk temperature inside the attic may be very slightly higher than the outside temperature, but the heat loss keeping the temperature down is due to the mass exchange of air, not conduction through the roof. Ventilation is the key, not the total heat conductivity of the roof (with or without snow). Anyway, "moisture under the accumulated snow" is NOT the same as the attic being so warmed by heat escaping from the insulated space that it melts the snow. If you have a properly ventilated attic it will be too cold to melt the snow (assuming the outside temperature is below freezing), so melt must be occurring from other sources (like sunlight). Water can take some time to freeze, especially if the bulk snow is very close to freezing itself, so it can stay wet for quite a while, even at night. |
actions · 2015-Feb-25 5:29 pm · (locked) |
| garys_2k |
to lutful
said by lutful:Imagine a warehouse with R1000000000000000000000000000 insulated walls and floor, with no windows or doors.
But it has a huge roof with only R10000000 insulation value and "properly ventilated attic" that you personally designed.
Do you really believe that you can store huge pots of boiling witches brew inside that warehouse forever, with no heat loss through the ceiling/attic/roof?
It is a rhetorical question. Of course you'll have heat loss to the attic, but with proper ventilation that heat gain in the attic will be overwhelmed with the fresh, cold air from the outside. The attic temperature will stay very close to the outside's, close enough that snow on the roof will have no impact on the heat loss from the inside of the warehouse. |
actions · 2015-Feb-25 5:31 pm · (locked) |
H_T_R_N (banned)
join:2011-12-06
Valencia, PA
1 recommendation |
to lutful
No one, including myself ever claimed that there would be no, none, nada, zip, zero loss. The sole reason and purpose of attic venting is so that the heated moist air that does get into that space is able to be carried out by the ridge vent and not permit that air from heating up the roof.
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actions · 2015-Feb-25 5:55 pm · (locked) |
| H_T_R_N |
to Scilicet
said by Scilicet:Yes, Yes, Yes and YES! Snow is 32 degrees. Insulation from anything colder. Stop. Haven't you been warned enough already? |
actions · 2015-Feb-25 5:56 pm · (locked) |
lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
to garys_2k
said by garys_2k:The attic temperature will stay very close to the outside's ... If you monitor actual temp at these different locations in a typical home throughout the winter months, you will notice that a-d varies with snow on roof, among many other factors. a) middle of attic space b) soffit vent c) ridge or highest vent d) roof surface, far away from any vent e) a few feet above roof surface, far away from any vent e is coldest d is higher than e b is higher than e c is higher than b a is warmest |
actions · 2015-Feb-25 6:25 pm · (locked) |
garys_2k
Premium Member
join:2004-05-07
Farmington, MI |
garys_2k
Premium Member
2015-Feb-25 8:10 pm
said by lutful:...you will notice that a-d varies with snow on roof, among many other factors. For sure, the largest one being wind. But what counts is whether or not the snow on the roof materially impacts your "a" temperature, that in the middle of the attic. With a properly vented attic (may or may not represent a "typical home," some of those were poorly built) the difference between a and e will be quite small, independent of the amount of snow on the roof. Note that with NO snow on the roof it will be subject to more solar heating (especially a dark surface), but whether you have half an inch or a foot up there it wouldn't make a material difference in the net heat loss from the house's conditioned space. |
actions · 2015-Feb-25 8:10 pm · (locked) |
lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
lutful
Premium Member
2015-Feb-26 12:38 pm
said by garys_2k:For sure, the largest one being wind ... a properly vented attic I will try one last time to use "common sense" to make an important point. Imagine a cold night with ZERO wind. There will be ABSOLUTELY NO AIR FLOW through the attic ... ... UNLESS some heat escapes from the living space.  |
actions · 2015-Feb-26 12:38 pm · (locked) |
garys_2k
Premium Member
join:2004-05-07
Farmington, MI
1 edit
2 recommendations |
garys_2k
Premium Member
2015-Feb-27 2:41 pm
said by lutful:... UNLESS some heat escapes from the living space. And it will, and the amount is easy to calculate. Say you have a 1000 sq. ft. attic with a total R40 (drywall, insulation and air films) on its floor, the living space below it is 70F, the attic interior is 10F. Heat loss from the living space to the attic is: Q = 1000 X (70-10)/40 = 1500 BTU/hour That heat, in a properly ventilated attic, will be lost to the outside (which may be at 0F) by convection through the vents. But if the attic was NOT ventilated it can allow the attic temperature to go so high as to allow condensation on its colder surfaces, leading to rot, mold and deterioration. The point of proper ventilation is to carry that heat away WITHOUT it needing to conduct through the roof's surface and possible snow cover. In other words, if snow on the roof IS helping trap heat in the attic (and materially affecting your heating bills) then you have inadequate insulation and/or ventilation. You CAN have the snow reduce your heating bills but if you do then you are almost certainly having much bigger problems. Let's take our attic example and assume there was no ventilation. Let's say the roof has a 4:3 pitch, so its area is 1250 sq. ft. and with no snow its net R value is 4. In this case the unventilated attic would be about 14.4F, the house would be loosing about 1390 BTU/h. With snow let's assume the roof's surface has a net R45, the house would now be only loosing 789 BTU/h, but the attic temperature would be 38.4F. Clearly likely to cause serious condensation issues and structural damage. The point of ventilation is to keep the temperature very close to the outside's temperature, to protect the roof's structure from moisture damage. That's why the (conventionally insulated attic's) mantra is to insulate the attic floor and ventilate the space, to keep the roof's inside surface dry. The reduced heat loss through the roof in that situation also can help prevent ice dams, but since those can also be caused by sunlight induced thawing, nothing you do in the attic could completely eliminate that. TL/DR: Yes, attics absorb heat from the house and that heat can travel through the roof. Depending on that to heat the attic by limiting ventilation, and allowing the attic to warm enough to reduce the house's heat loss, is a very bad thing. |
actions · 2015-Feb-27 2:41 pm · (locked) |
fartness (banned)Donald Trump 2016
join:2003-03-25
Look Outside |
fartness (banned)
Member
2015-Feb-27 9:50 pm
I don't know what size the chimney pipe is that leads from the pellet insert, but let's say it's 4 inches. If it got clogged and it's now 1 inch diameter, how would that affect the fire? |
actions · 2015-Feb-27 9:50 pm · (locked) |
H_T_R_N (banned)
join:2011-12-06
Valencia, PA |
H_T_R_N (banned)
Member
2015-Feb-28 7:16 am
If the flue was the only means for exhaust then the flame would be reduced. |
actions · 2015-Feb-28 7:16 am · (locked) |
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Termites to fartness
Anon
2015-Feb-28 9:37 am
to fartness
said by fartness:I don't know what size the chimney pipe is that leads from the pellet insert, but let's say it's 4 inches. If it got clogged and it's now 1 inch diameter, how would that affect the fire? yes it would and dangerous. |
actions · 2015-Feb-28 9:37 am · (locked) |
lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
to garys_2k
Unless you run a fan, you can't create sufficient ventilation on really cold and windless nights. Also, some obscure laws of physics will not follow the airflow to the vent.
a) The living space + insulation material together becomes a "black body" and radiates some energy in proportion to indoor-outdoor temperature difference.
b) R value drops with attic temperature, because of convection loops through the insulation material.
When the outdoor temp is FAR below freezing, increasing the attic temperature will help on both counts. The negative side effects (mold, ice dam, structural damage, etc.) can be avoided by still staying below freezing.
The physics is quite complex but snow on roof certainly lowers energy consumption for a typical home in a cold climate. People in eastern Canada can verify it on their monthly gas bills this year. |
actions · 2015-Feb-28 9:49 am · (locked) |
garys_2k
Premium Member
join:2004-05-07
Farmington, MI
1 recommendation |
garys_2k
Premium Member
2015-Feb-28 11:13 am
said by lutful:Unless you run a fan, you can't create sufficient ventilation on really cold and windless nights. I would like to see a cite from a reasonable source backing that up. The entire point of a large enough ventilation area to floor area ratio is to do exactly that, allow natural convection to take place even without wind. said by lutful:When the outdoor temp is FAR below freezing, increasing the attic temperature will help on both counts. The negative side effects (mold, ice dam, structural damage, etc.) can be avoided by still staying below freezing. Right, but that would take an active temperature management system in the attic with fans, shutters, sensors. Great in theory and maybe worth doing a cost/benefit analysis, but not something we have in residential construction right now. said by lutful:a) The living space + insulation material together becomes a "black body" and radiates some energy in proportion to indoor-outdoor temperature difference. OK, so heat transfer is not just via conduction but also via radiation. Again, if your point is that a warmer roof underside will reduce heat transfer I agree with you; my point is that that warmer roof underside can lead to very undesirable consequences. It's great to have lower heating bills that a poorly ventilated attic can provide, but you have to accept the health risks of the mold and inevitable structural damage that can take place because of it. said by lutful:The physics is quite complex but snow on roof certainly lowers energy consumption for a typical home in a cold climate. Modeling the house/attic/outside space problem isn't that hard, at least to the extent necessary to reach reasonably accurate conclusions (NREL has good models), but once again: if a "typical" house is getting a meaningful heating cost reduction because of a snow layer on the roof it very likely is also getting damage from condensation onto the structural members of the attic, particularly the roof deck interior. The physics is clear enough: If a layer of snow is helping to keep your HOUSE warm it's also keeping your ATTIC warm, and that warm attic can result in condensation and rot. If your attic insulation and ventilation are "adequate" then your attic will remain cold and any layer of snow will have at most a negligible impact on your heating bills. It's that simple. |
actions · 2015-Feb-28 11:13 am · (locked) |
lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
lutful
Premium Member
2015-Feb-28 1:33 pm
Assume these 4 homes are same size, have same amount of insulation on ceiling and walls, and are located in same Northern Ontario village. Assume homes 1A /1B have "open concept" attic design which does not let snow fall onto the insulation. Homes 1A/2A roofs are clear of all snow. Homes 1B/2B have snow on roof. We have ensured same airflow across the attic insulation layer and it is a very cold night. Which home will use the most energy? 1A Which home will use the least energy? 2B. But what about 1B and 2A? Which one will use less energy? |
actions · 2015-Feb-28 1:33 pm · (locked) |
H_T_R_N (banned)
join:2011-12-06
Valencia, PA |
H_T_R_N (banned)
Member
2015-Feb-28 3:42 pm
said by lutful:Assume these 4 homes are same size, have same amount of insulation on ceiling and walls, and are located in same Northern Ontario village.
Assume homes 1A /1B have "open concept" attic design which does not let snow fall onto the insulation. Homes 1A/2A roofs are clear of all snow. Homes 1B/2B have snow on roof. We have ensured same airflow across the attic insulation layer and it is a very cold night.
Which home will use the most energy? 1A
Which home will use the least energy? 2B.
But what about 1B and 2A? Which one will use less energy? If they have the exact same insulation and ventilation they will use the exact same amount, if all other things are the same. I will be interested in your explanation of how one uses more then the other though. |
actions · 2015-Feb-28 3:42 pm · (locked) |
I miss the Mike Homes forums.
