Old house thermal imaging

[Ashful]

So, mfglickman's recent thread about her ca.1758 house pushed me to get around to something I'd been meaning to do for some time, and the weather this week was perfect for it: thermal imaging of our ca.1773 house.

The house was built in three parts, the oldest and largest being built between 1773 and 1779, a kitchen addition in 1894, and a family room and garage addition in 1994. That last addition tied what was left of the original summer kitchen to the main house, and is entirely open to the 1894 addition. On the first floor where the stoves are installed, the two additions make up one heating zone (whether we're talking oil or wood), and the original 1773 portion is a separate zone.

The 1773 portion of the house (majority of the house) is 18" stone walls with plaster applied directly to the walls. No insulation, aside from the R-value of stone, although the mass acts like a giant capacitor. The 1894 kitchen appears to be poorly insulated framed walls, possibly balloon framing later modified by the installation of a master bath suite in the second floor of this addition. The 1994 addition is modern construction, very high end materials, but lots and lots of windows.

Each of my stoves sits in an old cooking fireplace, 18" thick stone on three sides, the rear wall being exterior in both cases. The location of the fireplaces will be obvious in the photos of the exterior, as a good bit of heat telegraphs to the outside. The stove in the 1994 wing sits maybe 12" from the rear wall, but the stove in the 1773 wing sits only 3" from the wall.

This morning, I was forced to let both stoves go out for the first time in a while. When I came home 12 hours later, I found the new (read: "well-insulated") part of the house sitting at the thermostat's set point of 62F, with the oil furnace working to keep it warm. The old (read: "un-insulated stone") part of the house was at 66F - 70F, and shooting the IR gun at the walls revealed the stone walls all around the wood stove were still holding 79 - 80F.

That's the back story. Next installment... images!

 

[Ashful]

Sorry for the low resolution, but that's what this FLIR can do. Outside temperature was 16F at time of photos.

Image of the front of the house. Oldest part is on left, 1894 kitchen addition in the middle (right under cross-hairs), and 1994 addition to the right of that. The big hot spot between the 1894 and 1994 additions is the front entrance, which I can now see radiates quite a bit of heat!



Closer-up on left (older) half of house. Note I am currently missing storms on the two third floor windows and one second-floor window. I bet you can guess which by the temperature color! All of the stonework is warm, indicating thermal transfer thru the walls, but only around 20 - 22F... which ain't bad on a 16F night. Heck, the soil might keep it almost that warm without me doing any heating inside. The kitchen addition is suprisingly "cool" in color. Thinking about this for the first time now, I don't have an insulation problem there... I just have too many leaks! That kitchen is very drafty.

The other thing that surprised me is how much heat is trapped below the porch roof on the old part of the house. There are no lights or sources of heat in that roof, so it's all natural to the structure. I wonder if folks knew something about this in the 1700's, which we've forgotten today.



End of house, or actually the original front of the house. Again, note the way the porch roof above the first floor (and the porch floor above the basement walk-out), really holds in the heat. I'm missing one storm on the second floor on this side as well... guess which!



Back of the old part, showing pretty clearly where one of my woodstoves sits, in this case 3" from the other side of that wall. Outside of the wall in this area is 38F, according to the camera, which I hope might be set up at least half right. The two windows radiating like hell on the far left edge of this photo (just above the FLIR logo) are in the newest addition, and are better than average modern double-pane, but with no storm windows.



Photo of the rear of the middle (1894) kitchen addition. The hot chimney is our oil-fired boiler, and that glass door with sidelights that's radiating like hell is a high quality but somewhat worn-out double-pane, ca.1990. The wing on the right is the 1773 part of the house.



Photo of the same courtyard, but this time showing the new wing. The hot chimney hiding under the "32.1" on the thermometer is the same oil-fired boiler. The hot fireplace and chimney in the middle of the photo is the old Jotul F12, sitting about 12" from the inside of the stone fireplace wall. Note the new double-pane windows in this addition seem to radiate hotter than the 1773 windows with storms.


Photo of more glass work on the new wing.



Photo of my crappy, poorly insulated, garage doors. That garage is likely only 50F inside, if not cooler. The thing that really caught my eye was the hot spots at the bottom of the walls, likely concrete block under the stucco.



Looking at these photos, I do not see any major insulation problems. After reviewing them, I think my troubles are more related to drafts than conduction. I'll get some indoor photos to try and prove that.

 

[ArsenalDon]

and now some of the same pic please...just regular pics? I am fascinated by your descriptions, have been for a while now...I want to see the outside and inside of your home

 

[Ashful]

and now some of the same pic please...just regular pics? I am fascinated by your descriptions, have been for a while now...I want to see the outside and inside of your home

Hah! I suspect the regulars here are flat out tired of looking at it. I posted several photos when begreen and I were debating where to put my second stove. I'll have to dig them up and repost tomorrow. Now... I'm off to bed!

 

[jdp1152]

So the moral of the story here is that your newer, well insulated house, leaks far less heat than you stone house? That's what I'm seeing.

 

[eyefish2]

I question your comments about the porch roof and porch floor really holding heat? I see these colors (porch and floor) being darker meaning they are cooler. To me, it seems these are cooler because they are away from the house. I would not think your structures exterior to the house would help it hold heat too much (theortically yes to some degree, but not that much). The higher temp below these indicates to me that your heat source is at that level. Very good IR pics of your house in the winter. Great pics and great interpretation.

 

[ailanthus]

Very cool pics, and a beautiful home.

I think it would also be helpful in terms of things you can easily change, to do the same thing from
the inside preferably on a windy day. That's the best way to pinpoint drafts and locate areas to caulk/spray foam, etc.

 

[jharkin]

I'm impressed that your roof shows up stone cold. If I could get somebody to flir my place is bet the roof would have some warm spots.

 

[EatenByLimestone]

How well does snow stay up on the roof? I can tell my warm roof spots from where the snow melts first.


Matt

 

[Ashful]

So the moral of the story here is that your newer, well insulated house, leaks far less heat than you stone house? That's what I'm seeing.

The first photo shows that the walls in the old part of the house is radiating much more than the new part, but the old single-pane divided-glass windows (with storms) are clearly better than the new double-pane windows (without storms), in terms of purely radiated heat.

I question your comments about the porch roof and porch floor really holding heat?

I was probably not clear in what I was inferring here. The I was guessing that the amount of heat radiating thru the stone wall should be roughly the same all over, as the house was roughly the same temperature indoors on all floors. However, it's clear that the exterior walls are warmest below that porch roof, so my guess was that the porch roof is limiting the amount of wind or some other factor, keeping the outside wall just a little warmer in that area. Now that you mention the possibility of a localized heat source, the second floor baseboard radiators would be roughly at the level of that porch roof.

I think it would also be helpful in terms of things you can easily change, to do the same thing from the inside preferably on a windy day. That's the best way to pinpoint drafts and locate areas to caulk/spray foam, etc.

Did this last night. I'll try to get the photos uploaded tonight.

I'm impressed that your roof shows up stone cold. If I could get somebody to flir my place is bet the roof would have some warm spots.

Yeah, I'm not sure what to make of that. It's a metal standing-seam roof, over plywood, over an old cedar shake roof on firring, so there's not the typical roof rafter heat lines you would see on new construction. Then again, I don't see that on the new part either, where the roof is typical "architectural" asphalt shingles on plywood. The old part of the house has the attic finished, and kept at 62F (unless a guest is staying up there), whereas the new part has un-heated attic space.

How well does snow stay up on the roof? I can tell my warm roof spots from where the snow melts first.

Interesting question. I have some photos of the house the day after snow, but they're from a sunny day, when melting may be caused by radiation of sunlight. I have some photos of the house in snow at night, but they're from the night it snowed, no time to show much melting. Also, that metal roof is so steep and slick, not much snow sticks to it in the first place.

 

[begreen]

How did you get the flir photos? Was the camera borrowed, rented, bought or did a pro come and check the place out? Have you had a blower door test done on the house(s)?

 

[Ashful]

I borrowed the FLIR from work, where I do a little bit of thermal imaging work as part of my job. It's not one of the real high end models, but I heard that even this little one costs something like $12k - $15k, more than this homeowner is going to spend on a camera!

Was just discussing the blower door test with my wife. I think that's the next step, but we're so swamped with projects at the moment, it might be a while before we move on that.

 

[begreen]

Thanks for sharing the images. They are quite informative. Yes, a house that size has to be a full time job. Just keeping it all clean would drive my wife nuts.

 

[Lumber-Jack]

I did a quick search on(broken link removed to http://www.shopflir.com/c1038/infrared_cameras.php). Oh boy, are they ever expensive! The resolution size of your images are 250X187, unless you've post edited them that would mean the camera that you took them with would be in the $6,000 dollar range.
I see the highest resolution IR cameras they have (on the website I linked) are only 640x480, and even with those I read in the specs that the sensor is only really 340X240. I guess those IR sensors must be pretty expensive to make? With the super megapixel sensors they have on regular digital cameras now a days, those tiny resolution sizes they have in those cameras seem a little inadequate, especially for the prices they are quoting. Of course I know almost nothing about IR cameras.

 

[Ashful]

These were taken on a FLIR T250, which I don't see as a current model on their web site. I'm not really sure of the price, as I didn't buy it, but I had heard it was over $10k. In any case, I suspect a large portion of the cost can be attributed to low manufacturing volume. Aside from the IR sensor, they're really not much more than a mid-grade digital camera, with the most poorly designed battery I've ever seen in my life (notorious for randomly falling out).

 

[Lumber-Jack]

Found it on a search. Looks like the price you were quoted was correct. (broken link removed to http://www.shopflir.com/p8171/flir_t250.php)

 

[jharkin]

These were taken on a FLIR T250, which I don't see as a current model on their web site. I'm not really sure of the price, as I didn't buy it, but I had heard it was over $10k. In any case, I suspect a large portion of the cost can be attributed to low manufacturing volume. Aside from the IR sensor, they're really not much more than a mid-grade digital camera, with the most poorly designed battery I've ever seen in my life (notorious for randomly falling out).

I don't know if it still holds today but back when they where only used by the military for night vision the sensors had to be cryogenically supercooled.

 

[Ashful]

I don't know if it still holds today but back when they where only used by the military for night vision the sensors had to be cryogenically supercooled.

A little off the topic, but there are two basic types of IR detectors: quantum (require cooling) and thermal (do not generally require cooling). The quantum detectors have higher sensitivity and speed, but the thermal detectors have flatter gain across the spectrum. The quantum detectors used to require liquid nitrogen or some other super-cooled liquid for their cooling, but often now use electronic cryogenic coolers, which are obviously more convenient (unless your facility is already plumbed for Nitro). FLIR makes both types, the T250 being an uncooled model.

 

[begreen]

These were taken on a FLIR T250, which I don't see as a current model on their web site. I'm not really sure of the price, as I didn't buy it, but I had heard it was over $10k. In any case, I suspect a large portion of the cost can be attributed to low manufacturing volume. Aside from the IR sensor, they're really not much more than a mid-grade digital camera, with the most poorly designed battery I've ever seen in my life (notorious for randomly falling out).

The FLIR unit has a bit more in it than a digital camera. There are several things working together in this unit. IR filtration, IR thermosensing, IR image processing, thermal info overlay, and they do this in color, not monochrome. Their units seem a bit overpriced, but it's a small market with limited sales.

 

[tfdchief]

Joful, what a beautiful home!

 

[Ashful]

These are the two photos of most interest to me:

The stove which is much closer (3") to the stone wall reads only 38F on the outside of the wall, whereas the stove that's much further (12") from the stone wall reads 49F on the outside. I guess the big wall is a decent heat sink, on a night when it's 16F outside.

I'm wondering if it's worth playing with some shielding between the stove and wall. Not much room there on the new install, and I fear a user-designed shield placed that close to the rear of the stove may inadvertently cause damage to the stove, by trapping and reflecting more heat at the back than the designer ever intended. Sure would be nice to limit what heat I'm contributing to the great outdoors, though.

 

[Ashful]

I think it would also be helpful in terms of things you can easily change, to do the same thing from the inside preferably on a windy day. That's the best way to pinpoint drafts and locate areas to caulk/spray foam, etc.

Here we go... on a fairly cold night. Can't remember how much wind there was last night, but it was maybe 10F outside at the time.

First shot shows where the cold air blows out between two cabinets, right in front of the sink. The cabinet surface is reading 54F at that spot, and given the rest of the cabinet is around 70F, the air coming out is MUCH colder than 54F. This is my wife's excuse for not keeping up with the dishes this week.



Next is a cold cupboard. When we open these things, we always feel the cold, not so much draft as just cold. Hearth Mistress has the same cupboards.



Cold kitchen window:



One of our many leaky doors, although interesting enough, this is not one of the very old doors. I'd put this one in the 1930 - 1950 time-frame, not 1700's. It's interesting that the cracked panel in the lower right is almost not visible without the camera. It's a very tiny crack, just enough to slip a sheet of paper into. The dark cold is oozing in thru that crack, and all around the perimeter. The hot stripe to the left of the door is a pipe inside the wall, supplying the second-floor radiators. I almost drove a screw thru this pipe when installing motion detectors, but felt the warmth thru the plaster at the last second, and realized what must be hiding in there.



Yet another leaky door, this one the original front-door of the 1773 wing. This photo shows a pipe running under the floor just inside the door, feeding first-floor radiators.



Another very old exterior door, this one the basement walk-out. There's a cord of wood piled just outside.



We have 7 exterior doors on the first floor, and one very large and old walk-out door in the basement... we're fighting a losing battle.

More to follow, but these were the most egregious examples.

 

[ArsenalDon]

The first photo shows that the walls in the old part of the house is radiating much more than the new part, but the old single-pane divided-glass windows (with storms) are clearly better than the new double-pane windows (without storms), in terms of purely radiated heat.

I was probably not clear in what I was inferring here. The I was guessing that the amount of heat radiating thru the stone wall should be roughly the same all over, as the house was roughly the same temperature indoors on all floors. However, it's clear that the exterior walls are warmest below that porch roof, so my guess was that the porch roof is limiting the amount of wind or some other factor, keeping the outside wall just a little warmer in that area. Now that you mention the possibility of a localized heat source, the second floor baseboard radiators would be roughly at the level of that porch roof.

Did this last night. I'll try to get the photos uploaded tonight.

Yeah, I'm not sure what to make of that. It's a metal standing-seam roof, over plywood, over an old cedar shake roof on firring, so there's not the typical roof rafter heat lines you would see on new construction. Then again, I don't see that on the new part either, where the roof is typical "architectural" asphalt shingles on plywood. The old part of the house has the attic finished, and kept at 62F (unless a guest is staying up there), whereas the new part has un-heated attic space.

Interesting question. I have some photos of the house the day after snow, but they're from a sunny day, when melting may be caused by radiation of sunlight. I have some photos of the house in snow at night, but they're from the night it snowed, no time to show much melting. Also, that metal roof is so steep and slick, not much snow sticks to it in the first place.

View attachment 91007

What a beautiful home! I understand it must be tough fighting the drafts...but your home is gorgeous!

 

[nate379]

Wow that's a huge house. You have a big family?

 

[Ashful]

I once did! Several early deaths and a few generations of only children really whittled it down, though. The place is not as big as it may appear, in fact very average, compared to the McMansions they were throwing up everywhere ten years ago. This one has more character, though.