Non-linear heatloss? What am I missing?

ChrisJ

I've been spending a lot of time trying to learn about thermodynamics and the heatloss of my home. The EcoSteam is really cool because I can watch how much heat I'm putting back into the building. Though it may not be exact, I'm betting it's very close.

I'm hoping maybe someone can shed some light on something I've noticed in my home, repeatedly regarding heatloss being non-linear.

If I setup the EcoSteam to work perfectly at a 20F ambient temperature it will work great during most of the winter. However, it seems that as it gets colder out my home's heatloss goes up more than it should. This becomes very apparent below 10F but really gets going below 0F. Around 0F my heatloss seems to be around 10,000 btus higher than expected.

My understanding is losses through solid objects such as walls and glass is linear so my best guess is infiltration?

Is heatloss through infiltration linear if we do not include effects of wind? My house is incredibly drafty due to many 150 year old poorly made windows, 3 doors and 3 very drafty crawlspace doors which I plan on fixing.

All of these observations were done at night so sun isn't a factor.

What am I missing and is it predictable? I understand this is not an exact science but I'd like to better understand what I'm seeing.

Jamie Hall

I don't know what your are missing -- but I've noticed the same thing. With about 10 years of data now, the best fit for my oil usage in gallons per day is 0.895 (for the water heater!) plus 0.249 times the degree-days for the day (that's the linear part) plus 0.0069 times the square of the degree-days. And I have no idea why...

ChrisJ

I love it when I'm not alone!

KC_Jones

Chris I see something similar. I don't have nearly enough data to talk about the exact temperature, but I did notice my EcoSteam needing the heatloss bumped up when the temps got really low. Again at night and with similar wind conditions to the higher OAT. Like I said I don't have the hard data other than seeing the house start losing temp until I gave an increase to the programmed heat loss in the EcoSteam unit. I would adjust mine and then give it a day or so and it seemed to work out, but now that the temps have warmed I have pushed the heatloss back down again and everything is fine. Honestly if I lived alone I probably would have left it alone since it was only a short time. This happened in February and, well let's just say the data I have I consider an out liar because of the severe weather. It is a bit curious though.

Jamie Hall

It would be an interesting academic puzzle except for one thing: I'm on "automatic" oil delivery, and the oil company uses a linear relationship to figure when I'm going to run out. Which means that they underestimate my usage on really cold days... which means the only times they run me out -- or threaten to -- are when it's really cold out.

Grr...

MarkS

@KC_Jones, Chris is testing an EcoSteam software update that lets you bump the heat loss curve up or down when the outdoor temperature is below or above temperature limits that you select. I think it's working well enough to release into the wild, if you want to give it a try.

Mark N

Doesn't heat loss follow a curve, therefore it is not linear.

BobC

Jamie,

i solved that by putting an elapsed time meter on my old AFG oil gun, I kept a daily log with DD and hours run. I was on will call and I made the call when I was down 150 gallons - I was never off by more than 5 gallons.

Bob

KC_Jones

I am game Mark. Chris and I compared notes on this the other day I just kept forgetting to mention it to you. Not sure if we will get much more cold weather to test it, but there is always next year. I am honestly and truly impressed with how well the system does work. There are so many variables in system design, house design, location orientation...etc. that it blows me away how well it has been working straight out of the box and with minimal tweaking on my part. I check it all the time just to watch it doing it's thing, but I have barely had to touch any of the settings since installation. This morning I had to change the system shut down temperature since I had it too low (55), but that was a dummy on my part.

bob_46

some thoughts , longer burner on time as we approach design means more combustion air equals more infiltration. I live in a solid masonry house no insulation in the walls . When it's really cold direct sun against the walls seems to make a big difference , I think it reduces the ∆T across the wall. I also think the mass of all the masonry gives walls a flywheel effect compared to a frame wall full of insulation.

ChrisJ

bob said:

some thoughts , longer burner on time as we approach design means more combustion air equals more infiltration. I live in a solid masonry house no insulation in the walls . When it's really cold direct sun against the walls seems to make a big difference , I think it reduces the ∆T across the wall. I also think the mass of all the masonry gives walls a flywheel effect compared to a frame wall full of insulation.

@bob

I don't have masonry walls, but on buildings that do can it be assumed the walls could also do the exact opposite if you have an extremely cold night and then a rapid warmup the next day?

ChrisJ

Surely someone has an idea of exactly what's going on, no?

Jamie Hall

BobC said:

Jamie,

i solved that by putting an elapsed time meter on my old AFG oil gun, I kept a daily log with DD and hours run. I was on will call and I made the call when I was down 150 gallons - I was never off by more than 5 gallons.

Bob

I'd try that -- but if you do the math you will see that I can go through 50 gallons of oil on a cold day without thinking about it. The will call has a three day window... too close for comfort. We used to have -- before the EPA got after us -- a lovely 2,000 gallon underground tank. I'd like to have something like that back, but with the environmental regs involved I simply can't afford it, and I can't find room in the basement for even another 330, never mind 2,000 -- besides, even if I could it would take up a lot of otherwise useful space!

Robert_25

Perhaps as the delta between room temperature and the outside temperature increases, the air exchange through the building also increases. Stack effect of the building, plus increased combustion air requirements (and whatever the draft control passes up the chimney) all have a cumulative effect. My days of record fuel consumption are never on the coldest day of the year...it is when the temperature is below zero and we are blessed with a 15-20 mph wind. -30 and calm is nothing compared to -15 with roaring wind.

icesailor

@Jamie Hall:

""" I'd like to have something like that back, but with the environmental regs involved I simply can't afford it, and I can't find room in the basement for even another 330, never mind 2,000 -- besides, even if I could it would take up a lot of otherwise useful space! """

Roth/Schute PE tanks are square and take up less space while containing more fuel than standard steel tanks.

Fred

@ChrisJ , could the fact that it takes more energy to maintain temps of radiator runs/risers on outside walls (especially if they are uninsulated) have anything to do with it?

ChrisJ

Fred said:

@ChrisJ , could the fact that it takes more energy to maintain temps of radiator runs/risers on outside walls (especially if they are uninsulated) have anything to do with it?

Hi,

I highly doubt it. 10K btu/h is a lot to lose through insulated piping especially with the amount I have.

I could see maybe a 1-2K increase but not 10K.

Fred

ChrisJ said:

Fred said:

@ChrisJ , could the fact that it takes more energy to maintain temps of radiator runs/risers on outside walls (especially if they are uninsulated) have anything to do with it?

Hi,

I highly doubt it. 10K btu/h is a lot to lose through insulated piping especially with the amount I have.

I could see maybe a 1-2K increase but not 10K.

Maybe it's a combination of several small environmental changes rather than any one issue. Some heat loss through outside radiator runs, colder air entering the structure when doors are opened, colder air whereever there is infiltration, change in chimney draw, others?

Rich_49

Air In / Air out . Air sealing and ACH are the factors you are looking at . Wind and differing barometric pressures have a huge effect on heat loss

ChrisJ

Rich said:

Air In / Air out . Air sealing and ACH are the factors you are looking at . Wind and differing barometric pressures have a huge effect on heat loss

@Rich

Is it safe to assume then, that the more drafty a house is, the more non-linear it's heatloss will be?

icesailor

I've always thought of heat loss like the weather. The higher the High and the lower the LOW, means the highest winds. The colder the low, and the colder the High, the harder the cold wind will blow. The higher the wind blows, the lower the outside pressure, and the harder the inside higher pressure, tries to equal the lower and colder outside.

Because wind speed isn't constant (it often doesn't blow at night when the sun is on the other side of the earth where it is windier) heat loss isn't linear in a measurable way. It will put computers into chaos.

ChrisJ

@icesailor

I'm comparing nights with similar calm windspeeds. For example, at least what I've observed is typically after the temperature stabilizes late at night winds die off almost completely.

icesailor

We sailors like to say that the wind goes down and the wind comes up when the sun comes up.

In the Northern Hemisphere, when you face South, the wind clocks to the left and flows to the right. It "bends" over the land. It bends to the right over the land. You want to go left/Port to be in the right side of the lift. If you want to be fast.

ChrisJ

icesailor said:

We sailors like to say that the wind goes down and the wind comes up when the sun comes up.

In the Northern Hemisphere, when you face South, the wind clocks to the left and flo

@icesailor

Eh?

I most often get wind out of the North \ North West. Sometimes, I get it out of the South though.

What's flo? Isn't she with Progressive?

Rich_49

Check this out . Same house with different ACH values , all else remains the same . One is leaky , the other , not so much

Rich_49

Here is the same house with P#@s poor air sealing . I used the detailed versions so everyone can see that R values , windows , all that stuff is the same . Infiltration becomes a HUGE factor in design .
I met a contractor on a job one time that designed a really decent system but it did not work well during conditions lime you describe . I'll give you a guess at what the problem was . Builder screwed up all the details and did not seal because , ready , " that's the way we have always done it " . Homeowner thought they were getting the best house and actually ended up with average . Don't worry though , it was all built to code . Right insulation R values , right windows , right doors , terrible envelope details at sills , around windows , around doors , at sheathing joints .
Poor **** undersized and had no idea . House as a system guys .

Only one file , sorry about the second upload .

ChrisJ

@Rich

Is there an easy way to see how the homes compare over a wide range of temperatures

I.e. 40f, 20f, 10f, 0f etc?

I had no idea you were in NJ.

Rich_49

Best and Average construction at 40* F , same house . Are you in Jersey also ?

icesailor

ChrisJ said:

icesailor said:

We sailors like to say that the wind goes down and the wind comes up when the sun comes up.

In the Northern Hemisphere, when you face South, the wind clocks to the left and flo

@icesailor

Eh?

I most often get wind out of the North \ North West. Sometimes, I get it out of the South though.

What's flo? Isn't she with Progressive?

Its still out of the West.

"Flo" is Flow. Because HH.com crashes regularly for me. Locks up my computer. Now, it saves what you are writing so you can go back and fix things.

ChrisJ

icesailor said:

ChrisJ said:

icesailor said:

We sailors like to say that the wind goes down and the wind comes up when the sun comes up.

In the Northern Hemisphere, when you face South, the wind clocks to the left and flo

@icesailor

Eh?

I most often get wind out of the North \ North West. Sometimes, I get it out of the South though.

What's flo? Isn't she with Progressive?

Its still out of the West.

"Flo" is Flow. Because HH.com crashes regularly for me. Locks up my computer. Now, it saves what you are writing so you can go back and fix things.

Nor-easters come in from the North East. We get them quite often and the wind is always from the North East.

Never the West.

http://en.wikipedia.org/wiki/Nor'easter

icesailor

ChrisJ said:

icesailor said:

ChrisJ said:

icesailor said:

We sailors like to say that the wind goes down and the wind comes up when the sun comes up.

In the Northern Hemisphere, when you face South, the wind clocks to the left and flo

@icesailor

Eh?

I most often get wind out of the North \ North West. Sometimes, I get it out of the South though.

What's flo? Isn't she with Progressive?

Its still out of the West.

"Flo" is Flow. Because HH.com crashes regularly for me. Locks up my computer. Now, it saves what you are writing so you can go back and fix things.

Nor-easters come in from the North East. We get them quite often and the wind is always from the North East.

Never the West.

http://en.wikipedia.org/wiki/Nor'easter

The wind starts in the West. When the front develops, it is to the West. As the low develops, the wind bends into the southeast, then East as the high and low interact with each other. The higher the high pressure, the more air falls out the high to feed the low. If the high is West of you, and the LOW is East of you, the wind will be from the West, or some variant. To be a "Northeaster", the wind goes from SE to East, then NE, it has to snow for a certain amount of time. Then, after the front goes away to the NE, the wind will swing around to the NW and blow. One set of weather comes from the Pacific Northwest. From across the pacific. The other East Coast weather comes from storms made up off Cape Hatteras, NC. All influenced by the Canadian Artic High.

ChrisJ

icesailor said:

ChrisJ said:

icesailor said:

ChrisJ said:

icesailor said:

We sailors like to say that the wind goes down and the wind comes up when the sun comes up.

In the Northern Hemisphere, when you face South, the wind clocks to the left and flo

@icesailor

Eh?

I most often get wind out of the North \ North West. Sometimes, I get it out of the South though.

What's flo? Isn't she with Progressive?

Its still out of the West.

"Flo" is Flow. Because HH.com crashes regularly for me. Locks up my computer. Now, it saves what you are writing so you can go back and fix things.

Nor-easters come in from the North East. We get them quite often and the wind is always from the North East.

Never the West.

http://en.wikipedia.org/wiki/Nor'easter

The wind starts in the West. When the front develops, it is to the West. As the low develops, the wind bends into the southeast, then East as the high and low interact with each other. The higher the high pressure, the more air falls out the high to feed the low. If the high is West of you, and the LOW is East of you, the wind will be from the West, or some variant. To be a "Northeaster", the wind goes from SE to East, then NE, it has to snow for a certain amount of time. Then, after the front goes away to the NE, the wind will swing around to the NW and blow. One set of weather comes from the Pacific Northwest. From across the pacific. The other East Coast weather comes from storms made up off Cape Hatteras, NC. All influenced by the Canadian Artic High.

Fair enough,
But as far as my house is concerned it's coming from the North East.

icesailor

@ChrisJ:

"" Fair enough,
But as far as my house is concerned it's coming from the North East ""



http://www.aos.wisc.edu/~sco/clim-history/stations/msn/madwind.html

Mark Eatherton

Chris J contacted me off line on this issue. I explained to him that there are basically three ways to compound infiltration.

1. Natural air changes, compounded by wind. (load calcs take this "normal" infiltration into consideration. Wind raises it significantly.)
2. Mechanically induced infiltration from exhaust fans, fuel consuming appliances etc.
3. "stack effect" which is the warm moist air rising, in a multi story building.

Item number 3 is probably the largest culprit in Chris' situation. It is a balloon framed 2 story house with poor fitting single pane windows, LOTS of them. As the temperature differential is increased, stack action increases, and adding heat to the space compounds the stack action even more.

Ballon framed homes are really a challenge to control infiltration in and I am not ware of a good way to insulate the exterior walls, short of opening wall/ceiling and installing fire stops in the balloon frame so that cellulose can then be blown in, and even then, expect to "lose" a bunch of insulation to unseen cavities, etc.

Chris said he could actually feel and see the draft rising in the stairwell of his home. Perfect candidate for stack action induced compounded infiltration.

Thanks for reaching out Chris. I wish I had the time to read all of the interesting posts here on the Wall. Sadly, I don't :-)

ME

icesailor

@Mark Eatherton:

Well, those old dead guys knew all about infiltration in their uninsulated homes. They always added a little bit for the unknown. Sort of like Jimmy Buffet's "Peanut Butter Conspiracy" song. Always leave a little extra for later if you need it.

Balloon framed houses are a bear and if you don't know what you are looking at, you can be screwed. Colonial Post & Beams keep everything in the room from the bottom sill to the nest floor above. The floor beams are all notched into the sill beams. Anything built after that, Greek Revival, Victorian up into the 1930's can be balloon framed. If you go into a cellar, and see that the floor joists are uneven on the bottom but straight across the top, and the joists have their bottoms notched so that all the ends are equal distance, its balloon usually framed. You can't see the ceiling/first floor connection but the wall studs run from the foundation to the roof sill plate. With a "Ribbon" let into the stud (Usually 2"X6" or more) to hold the floor joists. The joists are notched on the ends to equal a set dimension because the joists aren't equal width. An important function of the joist was to be pinned to the stud. That was supposed to keep the wall from "ballooning" out. Never cut a ribbon in a balloon framed wall. That's where "Fire Stops" came in. If you had a fire in the cellar, the draft brought the fire to the top floor and set the roof on fire. SO, fire stops on each floor. Don't cut out the fire stops.

Its too bad that the old IBR heat loss and piping design courses aren't offered anymore. I can't even find the new compressed books anymore. But they explain the whole process. Something I never see in any heat loss program on the market. The Slant-Fin heat loss explorer covers it all with no explanations of how the conclusions are reached. The whole concept is like blood pressure. Too low, and it leaks out of the cells. Too high and it blows them up or blows through veins and arteries. Just right, and everything works. Heating a building is like that. You have to give it enough pressure to keep it from collapsing from too much going out. Same with cooling only opposite. Too much trying to get in.

ChrisJ

My house was built sometime in the 1860s and there are likely no firestops. I don't think firestops started until much later.

I don't have diagonal sheathing or subflooring either as those also came out later. Nothing more than diagonal braces in the corners and the ribbon the second floor sits on. You can see the studs in the basement sitting on a 4x4 sill an the joists are notched to sit on the sill and on the foundation.

My dreams, which will likely never happen are to have the aluminum siding and clapboard pulled off, new Anderson 400 series WoodWright windows installed, firestops and insulation done and new sheathing and siding.

icesailor

Many Greek Revival homes had a 2 or 3 foot knee wall on the outside wall parallel to the ridge beam. The second floor joists sat on the ribbon. If the wall was especially long, they would break up the space into rooms. On walls coming off perpendicular to the outside walls, they often had steel/iron brackets made by blacksmiths with the ends flattened out. One end was lagged to the top plate and the other was lagged to a floor beam. . To keep the top part of the wall from bowing out from the downward and outward pressure of the rafters.

Don't cut out the iron strap/rods.

Oh the things I've seen. FWIW

ChrisJ

icesailor said:

Many Greek Revival homes had a 2 or 3 foot knee wall on the outside wall parallel to the ridge beam. The second floor joists sat on the ribbon. If the wall was especially long, they would break up the space into rooms. On walls coming off perpendicular to the outside walls, they often had steel/iron brackets made by blacksmiths with the ends flattened out. One end was lagged to the top plate and the other was lagged to a floor beam. . To keep the top part of the wall from bowing out from the downward and outward pressure of the rafters.

Don't cut out the iron strap/rods.

Oh the things I've seen. FWIW

No ridge beam and no knee walls. I think my dad said the rafters are a 9/12 so fairly steep roof though not crazy.

Not Greek Revival, I think if anything it's probably classified as Colonial.

The only strange thing I've noticed vs other balloon frame diagrams I've found online is, even though I can see the studs sitting on the sill in the basement, I can't see down the walls from the attic. All you can see is a double top plate.

Floor joists are 24" on center and studs appear to be approx 19" on center though both joists and studs aren't exactly evenly spaced. All lumber is full dimension and appears to have been cut with a circular saw. Lumber is of course also rough cut. Nails are type B cut nails.

As I said, no ridge beam, rafters simply sit against eachother and there are purlins run across them as the house previously had metal or slate roofing.

BobC

I have a 1918 balloon framed house and it's sometimes like heating with screen doors in place of the normal doors when the winds begin to howl. I have open bays in the attic which I have closed off as best i can but the real problem is the 12ft wide dormers front and back. Unless you want to tear down the ceilings on the first floor (I did install r19 when i gutted the kitchen 35 years ago) your SOL.

Maybe some small turbines in the wall cavities?

Bob

icesailor

Old houses are fun to look at. See how the old guys did it. I probably get as much pleasure at looking at old house construction as Steamhead gets from looking at old antique steam systems and what makes then run.

You can't see down the balloon framed wall from the top because the top plate is there for the collar ties and rafters to sit on. The below ceiling is connected to the bottom of the collar ties. Is the sheathing run vertical/top to bottom? Slate roofs are very heavy. Is the attic floor boarded? Are they wide pine boards? People take those boards up CAREFULLY to get the old pine and make things out of them. Cabinets and floors. They replace the boards with 5/8" plywood and insulate the ceilings. The only way you can get that special old pine board look is to have it on a floor for 100+ years. I've worked with guys that specialized in dismantling old barns in Vermont just to get the sheathing wood. They'd get over $10.00 per board foot for the wood.

ChrisJ

icesailor said:

Old houses are fun to look at. See how the old guys did it. I probably get as much pleasure at looking at old house construction as Steamhead gets from looking at old antique steam systems and what makes then run.

You can't see down the balloon framed wall from the top because the top plate is there for the collar ties and rafters to sit on. The below ceiling is connected to the bottom of the collar ties. Is the sheathing run vertical/top to bottom? Slate roofs are very heavy. Is the attic floor boarded? Are they wide pine boards? People take those boards up CAREFULLY to get the old pine and make things out of them. Cabinets and floors. They replace the boards with 5/8" plywood and insulate the ceilings. The only way you can get that special old pine board look is to have it on a floor for 100+ years. I've worked with guys that specialized in dismantling old barns in Vermont just to get the sheathing wood. They'd get over $10.00 per board foot for the wood.

No sheathing at all, just clapboard. Whoever built the house wanted it to breath.

Half of the attic floor is kind of boarded, not sure what they are other than old and not really nailed down. The sill is cedar, that much I know but I don't know what the house is framed out of other than it's incredibly hard to drill or nail things into.

Our second floor flooring is beautiful quarter-sawn yellow pine. Not sure what the first floor flooring was, but it might have been oak.