"Moving Heat" : Convection Air Currents in Your House

[SmokeyTheBear]

The Hubs made a Baltic Porter as the Christmas Beer this year. A few have "come out of the bottle" already. He says it's good.

Didn't I just see where you were bottling that a short time ago? Where did you get your stale beer to make the porter with or is this an imitation porter? Real porters were made from stale (old) beer at one time. I'm going to try some old wasail recipies this year I have a couple of different ales to use.

 

[SmokeyTheBear]

Joe, we are just having a normal hearth.com discussion. We welcome a good lively discussion. It helps get the cobwebs cleared out of our former functioning gray matter. Besides stirring the pot is what some of us do to get a discussion going. Wait until about the first of February when we are trying to find a nice way to tell folks to actually clean their stoves instead of just the burn pot.

 

[Harvey Schneider]

Hey, I didn't say one thing about in this particular situation I just laid out the three ways energy gets transfered.

All bodies above absolute zero radiate, no "glowing" needed, and what constitutes a significant amount varies .

Didn't mean to pounce on you. Perhaps I'm a little cranky today.
I was trying to relate what I've learned from designing aircraft probe de-icers to the issues related to stove heat distribution.
Yes, everything in the universe above absolute zero radiates energy, that is it glows. The amount of energy transferred at ambient temperatures in a home will not be noticed.

 

[becasunshine]

I just want to pop back in here to thank everyone, each and every one of you, for participating in this thread. I absolutely *love* this discussion. It's making me think, in both pragmatic and theoretical realms, and I love that. Value added, I'm picking up tips along the way, things that we can actually use- true value items.

Joe, I need to go back and read your response for detail. I'm in the middle of a couple of things here and I need to give your response the attention it deserves.

Smokey, I *think* it's a Baltic Porter, and we made it from a kit that we bought at a local home brew/craft brew store. I guess then it would be a "faux porter" because there is no stale beer involved. I will pass this information along to The Hubs (just about the time I make his head explode with spray foam and caulk) just for effect. I will also make sure that I know what kind of beer it is.

I have largely stopped drinking alcohol not because of any belief system or issue, but because one beer/drink/glass of wine puts me to sleep, and two beers/drinks/glasses of wine propel me straight into a hangover most of the time. I don't even have to go to sleep and wake up to get to hung over. =/ I find that I feel better, overall, when I don't drink alcohol at all.

When I do have some of Hub's beer, it is *very* good! and I do help bottle it, and I stand patiently with him at the home brew store when he chooses his kits, and I listen attentively to him discuss his ideas and his outcomes... you get the picture.

Harvey, interesting points- all of this talk of conductive energy transfer, radiant energy, etc. I think it has a practical application here in a specific way: the brick, block, lathe, plaster walls are COLD, even in the heated interior. The interior walls in the perimeter of the house are COLD to the touch during the winter, especially during the coldest times, and during the summer during very hot spells, the interior walls on the south/southwest exposure are downright toasty. This has to be affecting our heating and cooling costs...

Back in a bit- please continue- I am loving this discussion!

 

[Lyndon Fuller]

Ok so I will pipe in with my two cents about moving heat around my house. So every year I forget what works best and mess with it until I get it right.I have 12ft ceilings I'm my bed room and if I do nothing it will 74 in my living room and 61 in the bedroom. My house is wide open rancher for the most part. My bedroom is right off the living room and can be 12 degrees different easily. Every year I try moving the heat with ceiling fans and it never works. Even though I hate the noise and the cold air blowing in to the living room it is the only way to heat up my bedroom. Small 8in fan at bottom of the door blowing into the living room from bedroom can get the bedroom with in two degree of the rest of house. Works like a champ.

I love this thread, in a lot of cities, mine being Boston MA the city comes out and does an energy audit and one thing they offer is a 75 percent rebate on insulation, also huge rebates on replacing furnaces/boilers etc , I strongly advise you checking with your local city hall before you spend >

 

[Harvey Schneider]

all of this talk of conductive energy transfer, radiant energy, etc. I think it has a practical application here in a specific way: the brick, block, lathe, plaster walls are COLD, even in the heated interior. The interior walls in the perimeter of the house are COLD to the touch during the winter, especially during the coldest times, and during the summer during very hot spells, the interior walls on the south/southwest exposure are downright toasty. This has to be affecting our heating and cooling costs...

Of course it does. Any surface that is different in temperature from the air will set up a convection current in the air. That convection, couples the energy of the air to that of the surface. In that way it transfers heat into or out of the air. That convection is what causes drafts. If the wall is cold the draft is downwards, if the wall is warm the draft is upwards.

 

[Toddvt]

I like to use the fans i have built in place. Now i need to work on installing a thermostat on the pellet stove and some extra relays to turn the air handlers off and on as needed.

 

[Crazy Ivan from CT]

clear plastic over the windows even more modern ones helps

That works bigtime on drafts if you cant afford to re insulate!

 

[Countryboymo]

It has been in the teens and low 20's over the past 12 hours and my energy monitor shows two defrost cycles and other than that no heat strip use along with over a dozen heat pump cycles. The heat pump and air handler combined draws 3.5kw on average in the winter at 240v which is a ton better than 10kw of strips.

 

[becasunshine]

Temps are starting to drop here. We finally fired up the stove tonight.

I pulled a few random switch plate covers, plus a couple in which I remembered that the hole in the wall was rather generous. I bought some more spray foam today and I'll work on the larger gaps tomorrow, but for the most part, The Hubs is right: the gaps around the electrical boxes aren't large enough to work with the spray foam. Honestly, when I installed the insulating inserts behind the wall plates, I was working on getting through the process rather than examining each and every insert vs. the smaller gaps around the boxes. IIRC, the inserts covered the gaps. I only remember one box in particular where the hole in the wall was like a cave, and I had to piece together some additional material cut from overlapping inserts (double switches) to fill in the gap around the box- it is almost too big for the wall plate. I'll foam that one tomorrow.

In discussing the envelope, we realized that we'd failed to check the closet lights to see if there are big gaps around those boxes. The Hubs is going into the attic, pull back the insulation and check those fixtures. He's going to re-check the main fixtures up there as well. It's been a few years since we looked at them, so he's going to check them again to make sure that we've sealed them up appropriately.

I swear, sealing the gas water heater vent to the wall has helped with the draftiness in the house.

 

[becasunshine]

Joe, that was a great synopsis. We are still working on the sealing end of the equation. I agree with you, stopped is stopped. So we are working on stopped.

We can't do much about the brick/block/lathe/plaster walls. My understanding is that the construction isn't conducive to blown in insulation. So we'll work on what we can.

The attic is sitting at R49 plus the tented (attached to the rafters) radiant barrier. I have to admit, it's tempting (to me, anyway) to go all R-ONE THOUSAND! R-ONE MILLION! in the attic but for our environment we are probably right about at the sweet spot for ROI with attic isulation.

Maybe we can work on the insulation under the floor... We are going to pull back all that insulation in the attic and in the crawl space and make sure that the ducts are sealed as well. The ducts aren't as critical right this minute because we are using the pellet stove much more than the gas furnace, but we need to check those ducts before the cooling season.

 

[becasunshine]

OK, question, building guys- the HVAC tech re-sealed our gas water heater vent to the plaster wall with a dark gray mud type substance that took about 45 minutes to dry.

He also put the same sealant around the top of the furnace exhaust vent because it is right underneath the water heater vent.

I should have checked this more carefully while the HVAC tech was here, but I just now checked the underside/bottom of the furnace vent- and the sealant has aged and somewhat disintegrated there as well. There is a gap in the wall where it appears that a chunk of plaster has fallen out.

What is the name of this sealant? We can patch this ourselves if we know what we need to use.

EDITED: I think I've got it- furnace cement. Furnace cement? That's what I bought, anyway!

 

[Madcodger]

That should do it. Likely one tube is all you need.

 

[becasunshine]

That should do it. Likely one tube is all you need.

Yeah, I thought so as well- but one of our Big Box Home Improvement Stores didn't have it at all- and the other one had two buckets on their shelves, in half gallon sizes. That, incidentally, is the same size that our HVAC service tech went out and picked up to do the initial repair (he had used the last in his truck and needed to replenish.)

We are expecting the Arctic Blast here within 24 hours, so I purchased one of those half gallon buckets. Thank goodness it's cheap.

 

[Lake Girl]

Great thread folks. Beca - sorry to hear about your block wall story. Recommendation on the baseboard chaulking? That is one of my big complaints with our living room - that draft at the floor/wall transition. Plan on running masking tape on the wood flooring to keep that edge clean. We have to redo footings of the crawl space at our house. The sections we have redone to date are insulated more efficiently. Guess who's job that was It helps when it -26F like this morning.

Smokey, thanks for the builditsolar site - lots of great simple ideas for efficiencies. With the current temps, Hubby was just mentioning again that we should have built the in-ground house at our other lot. No electric to the site so the $10,000 that Hydro One wanted would be going to solar arrays.

 

[Harvey Schneider]

That is one of my big complaints with our living room - that draft at the floor/wall transition.

One of the causes of cold interior walls is attic air coming down through the holes drilled for electrical wires. Plugging the holes at the top with electricians putty (a non hardening clay) can significantly reduce those drafts. It can also be used to seal leaks around ceiling fixtures.

http://www.idealtruevalue.com/servlet/the-52462/Detail?gclid=COK4uonEnrsCFepQOgod3jYArQ

 

[Lake Girl]

No attic spaces in our house but plan to start looking at those electrical fixtures, plugs, etc. Thanks for the tip on the clay...

 

[becasunshine]

The Hubs is in the attic, gettin' crazy with the spray foam. Me? I'm doing just the opposite- I'm downstairs with all the windows opened and the exhaust fan in the laundry room sucking all of the stale, moist air out of the house. Opened the cell shades today and the windows were wet. Time to circulate some air and get some moisture out of the house, before the Arctic Blast arrives tonight. I know, this is counter-intuitive, but I will do this at least a few more times over the winter- the air out the entire house thing.

Also vacuuming one last time in case we lose power tonight/tomorrow. And laundry. We already have the kerosene stove and the Mr. Heater Tough Buddy ready. So this means we're gonna dodge the bullet, Central VA- nothing but rain for us. If we'd done none of these things- ICE-POCALYPSE.

 

[becasunshine]

Great thread folks. Beca - sorry to hear about your block wall story. Recommendation on the baseboard chaulking? That is one of my big complaints with our living room - that draft at the floor/wall transition. Plan on running masking tape on the wood flooring to keep that edge clean. We have to redo footings of the crawl space at our house. The sections we have redone to date are insulated more efficiently. Guess who's job that was It helps when it -26F like this morning.

Smokey, thanks for the builditsolar site - lots of great simple ideas for efficiencies. With the current temps, Hubby was just mentioning again that we should have built the in-ground house at our other lot. No electric to the site so the $10,000 that Hydro One wanted would be going to solar arrays.

LakeGirl, the caulk in between the quarter round and the hardwoods definitely seems to be helping.

We used caulk that goes on white but dries clear. It's barely noticeable to the eye. It is paintable when that time comes. I recently painted the baseboards so we should have a little bit of time on that.

I can definitely tell a difference in the draftiness.

I read recently that builders/trim finishers do not recommend caulking baseboards and quarter round to the floor. I tried to dig around to find out why. The only explanation I could find is that hardwoods expand and contract with temperature and moisture- so caulk can crack and separate and look like crap. There has to be some exception for old houses, lowered floor lines due to refinishing and settling, etc. We had to decide. We decided on clear caulk. The caulk we chose (latex with a silicon component, but still paintable and washable) touts "excellent flexibility" so perhaps cracking and separating won't be a huge issue in this application.

I guess that when the time comes, if it comes (and with caulk, that's probably a given) that scraping it out and replacing it will be oodles of fun- but for right now it's stopping the draft.

We need to address our crawl space as well. We have R19 under the hardwood floors/subfloor in the crawl space but I understand that the R value in that place needs to be higher.

I don't think we can seal this crawl space because of the re-drawn flood plain lines. FEMA would frown upon it, I'm afraid.

-26? I won't complain. I had every window in the house opened, and the whole house exhaust fan running, until about an hour or so ago. One last airing out of the house before we get this "winter weather," whatever we get.

 

[becasunshine]

OK, BUILDING GUYS AND ENGINEERS, ANOTHER QUESTION PLEASE:

The Hubs used spray foam or caulk around the electrical boxes in the attic that he could reach.

We have four closet lights and three ceiling fans that could not be accessed through the attic. None of these fixtures are inset. The closet lights are the classic pull chain fixtures into which one screws a bare light bulb, which hangs down from the fixture. The bulb can obviously dissipate its heat into the conditioned envelope below.

The ceiling fans are flush mount with a collar or a "beauty rim" that covers the base and the screws, where the base meets the ceiling. Obviously not inset. Both the motor and the light fixture are hanging down into the conditioned envelope of the house, where they can dissipate their heat. There are no transformers involved in these fans. One fan has a post-market (Hubs installed it) antenna for a wireless remote, but there is no transformer associated with this antenna.

We don't have a FLIR camera. I asked about renting one but our local Home Depot does not stock them in the rental tool area; evidently Home Depot tool rentals in other states carry them. =/ =/ So, without that tool, we are using the little hand held infrared thermometer to do a quick scan for air leaks.

When we shoot the IR thermometer at the place where the ceiling fan base (sans beauty rim, that was pushed down and out of the way) meets the ceiling, we can see that the temperature is slightly higher at that point in the ceiling, in each room, than it is on the rest of the ceiling. There is as much as a 4' - 5' difference in temperature, with the highest temperature right where the ceiling fan base meets the ceiling. This is true even for fans that Hubs was able to reach and seal from the attic. There is no transformer up in that space above the fan; there is no light bulb up there; there is no motor in that space either. We have no other explanation than that the ceiling fans are acting like little chimneys and drawing conditioned air out of the house and into the attic. Even the fans that are now sealed from above appear to be collecting and holding heat underneath this fixture- or perhaps spraying foam around the outside of the box didn't seal the fixture completely.

Interestingly enough, light fixtures such as the dining room chandelier- not, apparently, drawing air. The temperature where the fixture base meets the ceiling is within a degree or less than the temperature of the rest of the ceiling.

The thing about the ceiling fans acting as little chimneys- not the fans themselves in terms of their function, but the actual hole through the ceiling acting as a chimney- this might be confirmed by what we saw in the attic. When Hubs pulled back the batting insulation over the area of the ceiling fans, it was a bit dirty, and the dirt corresponded to the space between the floor boards of the attic, i.e. there was air movement at the ceiling fans. Air was being drawn upward through the underside of that white insulation, and the insulation became discolored in a pattern that exactly matched the gaps between the floor boards directly beneath that insulation.

This pattern was not apparent in other places in the attic.

Hubs caulked around the perimeter of the light fixtures in the closets with the same clear caulk we used around the baseboards. We couldn't think of a reason why not.

Hubs is using that gray "pool noodle" rope-like foam insulation that comes in a pre-packaged roll around the base of the ceiling fans, where they meet the ceiling. He's stuffing that cord of insulation around the perimeter of the base, closing the gap between the base and the ceiling.

We can't think of a reason NOT to do it; the motor isn't up there, the light bulb isn't up there, there is no transformer up there. We don't see a need to provide an escape route for heat to dissipate.

I'm asking- perhaps a few moments too late, as my husband has been diligently stuffing foam cording insulation around ceiling fan bases for the better part of an hour- if there is any safety reason why we should NOT do this? We can't think of any reason, and there's obviously an air flow issue in those areas.

If there's a reason, please tell us.

If not, well, the house temperature has gone up one degree in the past hour, since Hubs has been stuffing "pool noodle insulation" around the bases of the ceiling fans, with nothing else running but the pellet stove. So there's that... BUT ONLY IF IT'S SAFE.

 

[SmokeyTheBear]

I would expect the temperature above any operating fixture, be it a fan or light to be higher than several inches away from the fixture on the conditioned side of the fixture because it is close to a heat source and the heat is not being dissipated through a hole in the ceiling. I would expect the temperature to taper off the further you looked to the sides away from the center of the fixture.

As for it being safe depends upon the exact temperatures over time and the materials involved.

What happens in the case of recessed lighting is that insulating those needs to take into consideration the considerable amount of heat produced in a small space that must be dissipated.

ETA: A number of newer fixtures, some lights, and even some motors shut down when temperatures get above certain temperatures in a fixture. I have 4 (used to be 5) three light spot fixtures that have temperature sensors. A lot of CFLs have temperature sensors as well.

 

[Bruins4877]

Wow...I'm glad I found this thread. I have been lurking it for the past few days and have done quite a bit of what has been discussed. I'm sure the toilet paper test was discussed somewhere else on these boards, but this was the one I first saw it on. I use those fans that are up in the corner of the doorways to move the heat from the family room (where the stove is) to the other rooms of the bottom floor. I turned them all off to see how the natural air flow was working. I had my fans going the wrong way so I was really moving the air against the natural flow. Now I have all the fans going the way the natural airflow in the house and all rooms are not perfectly warm, but are certainly warmer than they were. Since buying the house 4 years ago I have been tearing down walls to replace insulation (R-7 insulation in the walls...DOH) and windows. I have used R-13 in the walls, then putting rigid foam up before sheet rocking. I never thought about putting the outlet and switch foam on the interior walls, but that has been done. Tomorrow I get out the spray foam gun and head into the attic. My wife thinks I have a spray foam problem already, but she ain't seen nothing yet, LOL. Thanks for everyone who has contributed to this thread. I constantly feel drafts in this house and my wife thinks I'm crazy. She won't think I'm crazy when we are sitting in our nice comfy WARM living room with no drafts what so ever Thanks again....and I'll keep lurking this thread, LOL.

 

[becasunshine]

I would expect the temperature above any operating fixture, be it a fan or light to be higher than several inches away from the fixture on the conditioned side of the fixture because it is close to a heat source and the heat is not being dissipated through a hole in the ceiling. I would expect the temperature to taper off the further you looked to the sides away from the center of the fixture.

As for it being safe depends upon the exact temperatures and the materials involved.

Smokey, I may be wrong/incomplete here, but there should be no additional heat in the interior of the fixture while the fixture is OFF, which all of the ceiling fans were this evening while we were working on them. The wires that service the fan motor and the light kit go through a hole in the middle of the fixture, but after the connections were made between the house supply side and the fixture wires, the splices were capped and they are stowed in the box, above the plain of the ceiling.

The insulation is the gray cord type insulation that one typically tucks into big gaps, say around thresholds, big gaps around window frames, etc. In this application, it is in between the surface of the ceiling and the round base of the ceiling fan where it abuts the ceiling. The screws that connect the fan to the bracing in the ceiling go through this base, and into the bracing. The bracing is attached to joists in the ceiling. BUT- the take home message is that the gray cord insulation is in the conditioned space of the house, on the "living space side" of the ceiling fan, in between the surface of the ceiling and that round base. And then the beauty rim snaps over that base to hide the screws.

Three ceiling fans could not be accessed from the attic at all. This was the only way that we could see to seal them. ??? Is there another way?

We couldn't see a fire hazard here because there's nothing producing heat in that space- the motor and the light fixture are below all of this and in the living space. BUT if we are wrong, please tell us!

 

[becasunshine]

Tomorrow I get out the spray foam gun and head into the attic. My wife thinks I have a spray foam problem already, but she ain't seen nothing yet, LOL. Thanks for everyone who has contributed to this thread. I constantly feel drafts in this house and my wife thinks I'm crazy. She won't think I'm crazy when we are sitting in our nice comfy WARM living room with no drafts what so ever Thanks again....and I'll keep lurking this thread, LOL.

Thank you, Bruins4877, but be careful about lurking ME- I'm learning as I go along! I hope I'm getting this stuff done correctly and safely; that's one reason why I keep coming back here, reporting in and asking additional questions. I imagine that working with *any* house is challenging in this regard, but it's especially interesting in a 54 year old house.

At least we aren't dealing with the really old type of electrical service wiring... that would be really sporty!

 

[SmokeyTheBear]

Smokey, I may be wrong/incomplete here, but there should be no additional heat in the interior of the fixture while the fixture is OFF, which all of the ceiling fans were this evening while we were working on them. The wires that service the fan motor and the light kit go through a hole in the middle of the fixture, but after the connections were made between the house supply side and the fixture wires, the splices were capped and they are stowed in the box, above the plain of the ceiling.

The insulation is the gray cord type insulation that one typically tucks into big gaps, say around thresholds, big gaps around window frames, etc. In this application, it is in between the surface of the ceiling and the round base of the ceiling fan where it abuts the ceiling. The screws that connect the fan to the bracing in the ceiling go through this base, and into the bracing. The bracing is attached to joists in the ceiling. BUT- the take home message is that the gray cord insulation is in the conditioned space of the house, on the "living space side" of the ceiling fan, in between the surface of the ceiling and that round base. And then the beauty rim snaps over that base to hide the screws.

Three ceiling fans could not be accessed from the attic at all. This was the only way that we could see to seal them. ??? Is there another way?

We couldn't see a fire hazard here because there's nothing producing heat in that space- the motor and the light fixture are below all of this and in the living space. BUT if we are wrong, please tell us!

Poor connections inside that box can cause resistance heating to take place. If the joints are properly done then the insulation is very likely blocking some of the heat loss that was there if there is a bit of a temperature rise. Again it is a matter of the exact temperatures over time and the materials involved at that location.

90 isn't a problem.

If you are worried about the insulation you are using I'd get some Roxul at a big box it is fireproof.