# The No heat basement experiment



## Seasoned Oak (Nov 14, 2014)

Im trying to insulate a mostly underground basement so it remains above freezing no matter what the outside temps are with no additional heat.
Im rehabbing the home and it goes with out heat for days at a time and i have water in the basement. While im working i have wood heat. 
Being the average underground temp around here should be about 50 degrees it is possible.
I do know of other 1 story homes with undeground basements that never go below freezing with no additional heat even on the 1st floor due to the warmth coming from below.
This can be very usefull information for part year residences,cabins ,vacation homes ect.


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## newburner (Nov 14, 2014)

Our basement is unheated and uninsulated as well. It always stays between 50-55° year round due to geothermal heating.


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## Seasoned Oak (Nov 14, 2014)

newburner said:


> Our basement is unheated and uninsulated as well. It always stays between 50-55° year round due to geothermal heating.


Well you do have some heat coming off the GEO equipment and water heaters and some from above. My uninsulated basement where i live stays above 70 with no heating units just from the heat coming off my solid fuel boiler and stoveipe in the back room and total basement is 1000 SF.
The one in experimenting with will have zero heat input on weekends when im not there to operate the woodstove.


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## newburner (Nov 14, 2014)

Seasoned Oak said:


> Well you do have some heat coming off the GEO equipment and water heaters



By "geothermal heating" I mean the natural heat from the earth.

There is nothing in my basement that creates any heat.


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## Circus (Nov 14, 2014)

Seasoned Oak said:


> The No heat basement experiment   Im trying to insulate a mostly underground basement so it remains above freezing no matter what the outside temps are with no additional heat.
> quote].


 
That's not really an experiment. It's common knowledge and practice


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## woodgeek (Nov 14, 2014)

I get the concept, but in a region where average January temps are close to freezing (like SE PA), it doesn't take a lot of BTUs to keep things above freezing.

Even so, I suspect that passive solar gain add a few degrees on average too.


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## Where2 (Nov 14, 2014)

I have one of these "experiments" also. I would like to log the temperatures during the entire winter, without being at the site or having any PC there. Has anyone found any temperature data loggers with downloadable memory for a reasonable cost? I need to be able to set them up and ship them for deployment.

Having a humidity reading wouldn't hurt either, if the additional expense doesn't break the bank.


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## Seasoned Oak (Nov 15, 2014)

Circus said:


> That's not really an experiment. It's common knowledge and practice


Large number of variables. How many walls are underground and how deep. Walls part underground and part above. Windows and doors. Air sealing. thickness and composition of walls.


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## Seasoned Oak (Nov 15, 2014)

woodgeek said:


> I get the concept, but in a region where average January temps are close to freezing (like SE PA), it doesn't take a lot of BTUs to keep things above freezing.
> 
> Even so, I suspect that passive solar gain add a few degrees on average too.


No solar gain in a basement
Last year the water and well pump froze solid in this basement. I figure i can probably get close to no freeze situation with air sealing alone. I also plan to add sheet foam to exposed outside walls to try to keep it above 40.


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## Seasoned Oak (Nov 15, 2014)

newburner said:


> By "geothermal heating" I mean the natural heat from the earth.
> There is nothing in my basement that creates any heat.


 OK i follow. I suspect you get a small amount from above


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## woodgeek (Nov 15, 2014)

I was thinking solar gain on the upper story....if the upper is above freezing, it helps the basement.

I think a big issue is basement airsealing. Lots of folks freeze pipes when the basement is at 40°F or warmer because there is a cold 'jet' of infiltrating air from a exterior penetration or under a gap n the sill.


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## jebatty (Nov 15, 2014)

> Has anyone found any temperature data loggers with downloadable memory for a reasonable cost?


 Google "temperature logger" and you can find lots of them.


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## Circus (Nov 15, 2014)

woodgeek said:


> airsealing. Lots of folks freeze pipes when the basement is at 40°F or warmer because there is a cold 'jet' of infiltrating air from a exterior penetration or under a gap n the sill.


 
Mouse holes plague me. I've found entire interior hollow spaces like floors or walls ice cold from them. Those illegitimate offspring!


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## Seasoned Oak (Nov 15, 2014)

woodgeek said:


> I was thinking solar gain on the upper story....if the upper is above freezing, it helps the basement.
> I think a big issue is basement airsealing. Lots of folks freeze pipes when the basement is at 40°F or warmer because there is a cold 'jet' of infiltrating air from a exterior penetration or under a gap n the sill.


No windows in the upper story yet. Upper story is actually colder than the daytime highs due to overnight temps. Lots of air infiltration though. iv sealed the worst ones. ONce it really gets cold out it will help me find the others. Then on to foam sheathing on walls.


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## STIHLY DAN (Nov 15, 2014)

How are you going to make the foam look half decent?


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## Seasoned Oak (Nov 15, 2014)

STIHLY DAN said:


> How are you going to make the foam look half decent?


Thinking of covering it with something also to prevent damage


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## STIHLY DAN (Nov 16, 2014)

Interested in what you cover it with.


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## Seasoned Oak (Nov 16, 2014)

I have a lot of the DRI-VIT  plaster cement that goes over foam. You see it everywhere on chain restaurants like mcdonalds.
First a fiberglass mesh for strength then a scratch coat and a surface trowel coat for looks.


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## WiscWoody (Nov 16, 2014)

My basement never freezes even with one wall being a framed walk out wall. Even last winter with our near 8000 heating degree days. I figure the upstairs must radiate some of its heat downwards.


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## Seasoned Oak (Nov 17, 2014)

WiscWoody said:


> My basement never freezes even with one wall being a framed walk out wall. Even last winter with our near 8000 heating degree days. I figure the upstairs must radiate some of its heat downwards.


It does , plus the ground radiates heat upward. If the space is tight and mostly underground it should not freeze. My project has no heat anywhere when im not there. So its fighting cold from above as well as exposed walls. A present it stays 10 degrees above outside temps which is not that good. hope to  get it between 20 and 30.


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## jebatty (Nov 17, 2014)

Basements .... when our walkout basement gets down to about 50F I start adding some electric heat to maintain a 50-55F temperature. The basement is about 1500 sq ft, one large unfinished area and two smaller finished areas. The unfinished area is partially insulated with foam on one exterior wall and interior fiberglass on another exterior wall. The finished rooms are fully insulated. All can be separately heated. Usually the basement drops to 50F in early December, this year it already is at the 50F level. I keep thinking about excavating around the foundation to add 2-4" foam board. That thinking has diminished with our PV system that now provides sufficient net metering credits to cover the cost of the electric heat.


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## DickRussell (Nov 17, 2014)

STIHLY DAN said:


> Interested in what you cover it with.



Some of the ways this can be done are described here: http://www.greenbuildingadvisor.com...ght/how-finish-exterior-foundation-insulation

I used the technique of modified surface bonding cement troweled over self-stick mesh, to around 1/8" thickness. It's been three years now, and I haven't seen any cracking or chipping. The surface is tough, although I'm sure that if I hit with a hammer I'd do some damage. Even up close, it looks like gray concrete. I applied the coating to perhaps 6" below grade. It took time applying it, and I had to work with small batches, no more than I could trowel on and smooth out in ten minutes, or it would stiffen and be difficult to work. If I look closely, I still can spot the places where one batch ended and the next began.

If I had to do it all over, I suspect I'd use EPS rather than XPS (cheaper), and apply it all on the inside of the walls, with studs on the flat for creating wiring cavities and for screwing on sheetrock (necessary for thermal/ignition protection inside). Certainly this makes more sense than excavating a foundation that already has been backfilled.

For sure, insulating the walls keeps the basement much warmer, although in my case there is R-20 foam under the slab as well. But in the unheated attached garage, the framed walls and ceiling are insulated, as is the door, the frost walls are insulated on the inside down to footings, but the slab itself is not insulated. At the coldest part of last winter, with multiple days in the single numbers and below zero, the coldest it got out there was 37 F. Yes, deep ground heat can keep the space above it from freezing, as long as you keep that low level heat from escaping to frozen ground and cold air with insulation.


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## Seasoned Oak (Nov 18, 2014)

First really cold night with no heat and a surprising 40 Degrees at floor level. Outside temp around 20. On air sealing alone. Still a lot of air sealing to do ,can see small amounts of daylight in too many places. Right now with the wood stove going its around 60.


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## begreen (Nov 18, 2014)

Keep sealing those leaks. A 1/8" by 72" crack is equal to having 3" x 3" hole in the wall.


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## Seasoned Oak (Nov 20, 2014)

Since i sealed it up it hasnt gone below 38 Deg. Ill check it again today after 2 full days with no added heat and below freezing outside temps 24/7 . Edit:  Still 38 .  Colder outside, but temps do not seem to go lower than 38 so far, with no heat at all added.


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## begreen (Nov 21, 2014)

Sounds like some cold floor boards.


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## ihookem (Nov 21, 2014)

My basement never gets below 55 degrees. Most years now , sinse I insulated the inside walls it doesn't get below 58. I have 2" styrofoam outside and R11 inside .


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## begreen (Nov 21, 2014)

I insulated the crawlspace in 2006. We noticed the warmer floors right away the next winter. That meant less heating to feel comfortable.


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## Seasoned Oak (Nov 22, 2014)

begreen said:


> Sounds like some cold floor boards.


It heats up fast once i get there and fire up the wood stove. Basement will go to 70 in less than an hour. I use a barrel stove in the basement and an englander NC30
on the first floor.Basement gets a lot warmer than 1st floor a lot quicker too. Home was completely gutted so most places i  can see the backside of the exterior sheathing boards and some daylight. Now in the process of sealing off the 2nd floor stairwell to keep heat confined to the first floor.


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## jdp1152 (Nov 22, 2014)

I have about 50% of my basement subterranean.....it never even flirts with less than 40 down there with no insulation.  I have 5 small basement windows, one entry door, and two garage doors (now insulated garage doors as of this summer) that lead to an entry door.  Only issue I have is that when I have the inserts running in the main living space, the geothermal doesn't run so the air in the ducts gets cooler and when they inevitably let the temp drop in the main living space, it shoots out a burst of cold air which decreases efficiency of the system.  I only let the electric back up activate when it's around zero or below outside since the heat pump will catch up eventually and experience tells me it's cheaper than the back up.  I did do some air sealing from garage to basement and some insulation/soffit work around the exposed ducts in the garage, but haven't had that in place long enough to gauge efficacy during the winter.  I would like to eventually insulate down there (aside from the rim joist, which I have spray foamed), but until I know what I actually want to do with it (if anything), I'm at a bit of a stand still.


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## Seasoned Oak (Nov 23, 2014)

ihookem said:


> My basement never gets below 55 degrees. Most years now , sinse I insulated the inside walls it doesn't get below 58. I have 2" styrofoam outside and R11 inside .


That sounds like a lot of effort and expense for just a 3 degree improvement. Looks like the law of diminishing returns applies here. Iv been able to achieve great improvements with just air sealing alone. Im afraid future improvements will be both much more costly and less effective.


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## TradEddie (Nov 23, 2014)

I have a block wall basement, mostly underground, that would get to almost freezing (ice on insides of windows) even with a propane furnace down there running five days/week (downside of sealing ducts well). I airsealed, installed a proper door at the foot of the bilco steps, insulated inside walls with 1" foam, and last year it never went below 55F even before insulation was complete. Even now, there's no way I'd leave home for a week in Winter without turning off the water.

If you do go with foam interior, beware of codes requiring a fire-proof covering. I simply glued drywall on top of the foam, with the right glue the drywall ripped before the glue, way stronger than screws. 

TE


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## CaptSpiff (Nov 25, 2014)

TradEddie said:


> ...If you do go with foam interior, beware of codes requiring a fire-proof covering. I simply glued drywall on top of the foam, with the right glue the drywall ripped before the glue, way stronger than screws.TE


 So what was the name of the glue?


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## Seasoned Oak (Nov 25, 2014)

TradEddie said:


> I I simply glued drywall on top of the foam, with the right glue the drywall ripped before the glue, way stronger than screws.
> 
> TE


I would think the foam would rip before the drywall or the glue.


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## semipro (Nov 25, 2014)

TradEddie said:


> I simply glued drywall on top of the foam, with the right glue the drywall ripped before the glue, way stronger than screws.


I did the same thing with good results in one area where i needed more space around a toilet for code compliance. 
I used Loctite PL300 Foamboard glue.


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## begreen (Nov 25, 2014)

Seasoned Oak said:


> It heats up fast once i get there and fire up the wood stove. Basement will go to 70 in less than an hour. I use a barrel stove in the basement.


That's not no heat.


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## Seasoned Oak (Nov 26, 2014)

begreen said:


> That's not no heat.


The no heat part is overnight and weekends. Barrel stove goes out quickly after you stop filling it. Latent heat dissipates within a few hours. At this point there is still zero insulation anywhere in the house and no drywall yet. I have a 220 gallon rain catchment system in the basement which froze last year and ruined the pump. This year so far with air sealing
it has stayed above 38 with overnight outside temps in the teens and daytime temps in the 20s. We will see what happens once it gets colder.


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## Seasoned Oak (Nov 28, 2014)

My 220 Gallon rain catchment system is already full after only being installed about 2 weeks. It covers about a third of the roof surface. Were in a rain deficit still, but im surprised it filled so fast.


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## TradEddie (Dec 2, 2014)

Seasoned Oak said:


> I would think the foam would rip before the drywall or the glue.


With the "wrong" glue, the foam would give way behind the glue, although even that took far more force than pulling out a drywall screw, but with foamboard glue, it didn't. I tried a few small test pieces as I was gluing and the drywall tore first, and it took a lot of force.

TE


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## Seasoned Oak (Feb 12, 2015)

Update: I have the floors torn out above and now the cold just drops down into the basement and its freezing in there once again.


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## Wisneaky (Feb 12, 2015)

Basement temps have a lot to do with where you live. Here in Wisconsin there is 4-6 feet of frost in the ground and temps drop below zero a lot of days. Basements here get very cold and without some sort of heat in them pipes will freeze and burst. Some towns around here ask that you keep a faucet on so the water lines in the ground don't freeze also. Also want to add I've seen people spray foam the basement walls and that keeps it very warm.


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## ihookem (Feb 15, 2015)

Seasoned oak, you have to have an awful lot of air coming in. My 2200 sq ft basement never got below 52 degrees. You are loosing a lot of heat. I have a new home. The floor truss cavities are closed cesll foam.. The outside has 2" foam and the inside is insulated with some 2" foam and fiberglass batts . It is framed and it has 1/4" plywood over it. . The only bit of heat is from the water heater. It might get some from the 1000 ft of staple up pex but before the pex it never got below 50 degrees anyway.You could raise your temps 10 degrees if you insulate.


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## Seasoned Oak (Feb 15, 2015)

The first and second floor of this rehab is still gutted and yes there is a lot of air coming in. Before i tore out the floors to replace all floor joists and subflooring iwas maintaining about 40 Degrees with no heat. Without some of the floors complete i cant stay above freezing so i have heat tapes on the whole house sewer line trap and another snaking through my rain water collection barrels. so far so good.


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## Wisneaky (Feb 16, 2015)

ihookem said:


> Seasoned oak, you have to have an awful lot of air coming in. My 2200 sq ft basement never got below 52 degrees. You are loosing a lot of heat. I have a new home. The floor truss cavities are closed cesll foam.. The outside has 2" foam and the inside is insulated with some 2" foam and fiberglass batts . It is framed and it has 1/4" plywood over it. . The only bit of heat is from the water heater. It might get some from the 1000 ft of staple up pex but before the pex it never got below 50 degrees anyway.You could raise your temps 10 degrees if you insulate.


With that 2 inches of foam on each side plus the batts your sitting on about r30 worth of insulation. Sounds like the op has no insulation so he isn't going to be able to keep it above freezing without heat.


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## Seasoned Oak (Feb 16, 2015)

Wisneaky said:


> With that 2 inches of foam on each side plus the batts your sitting on about r30 worth of insulation. Sounds like the op has no insulation so he isn't going to be able to keep it above freezing without heat.


I have been keeping it at 40 with no insulation except now that i have the floor torn out above. The cold drops right down and overwhelms the 40 degree floor. As soon as i can get the new floor in above ill be back above freezing. should take about 2-3 days


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## ihookem (Feb 16, 2015)

I bet you will be fine. When my house burned down I was concerned about my water freezing in the drain tiles.  They never froze in the crock sump neither, not even a little bit.  The coldest the basement got was 23* and it was a home with a hole in the roof but not completley open. You should be ok against frozen sump water but I don't know about the water pipes.


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