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Xringer 10-19-13 03:18 PM

Using attic heat to warm up basement
The goal of this project it to pump solar warmed air from the attic, down to the unheated basement.
For two reasons:
I want to be able to work in the basement when during the winter.
(When it's 60-65F down there).
And, I want to provide a little warm air for the A7 Airtap (DHW ASHP).

I have an exhaust blower already installed in the basement.
The air intake is 10" off the basement floor. It's suppose to pump the cold air into the outdoors.

My CAI controller is using temperature and RH as inputs and X10 for control.
I've had success in using this fan during this summer, pumping out
the cool damp air, while the outdoors RH and temp are within acceptable ranges.

This new 200 cfm fan (coming next week) will be installed in the attic.
It will also be controlled by X10.
4" inch 200 CFM Inline Fan Duct Booster Exhaust Vent Blower Hydroponic Radon M 4 | eBay

I plan to use this 4" dryer duct hardware for the attic install.
The tubes are 8' x 4" and should fit the Tjernlund M4 blower.

The dryer exhaust port will be mounted on the ceiling of the small back hall
(or landing) that connects the basement stairs to the kitchen and back entry door.
This 'hall' is where the pull-down attic stairs is located, so the install shouldn't be too hard.

Using the outdoor RH reading and attic temperature (and time of day),
the CAI controller will turn on both blowers when the RH is low
and the sun has heated up the attic.
I'll post the control program after I get it debugged.

I've been thinking of a method of closing the plastic flap inside the dryer exhaust port.
It would be nice to keep warm air from floating up into the attic during the night.
Some fishing line with one end weighted, thru the flap, connected to a hook on a roof rafter.
The light weight will pull the flap up, and it will be easy for the air flow to push down (open).

Xringer 10-20-13 02:24 PM

Dusty part done
Here's a "Before" picture of the back door and pull-down attic stairs.

Here's the "After" pic with the dryer vent installed.
(Notice the roof rafter? I left the attic light on)

Because it's one inch of sheet-rock, I used long deck screws and used PVC plates
on the top side, to act as 'nuts' to hold the vent from being shaken loose
by vibration from the blower.

The hole saw used, was 4.125", but the fit was too tight. I had to sand down the ID of the hole.. MK Morse AV66 Hole Saw, 4-1/8-Inch Bi-Metal Boxed: Home Improvement
I used a dust mask! And went out on the deck to shake off.. Looked like a ghost.. :eek:

Not real sure about the wisdom of using this directional vent.
It's nice that it will point the air flow in the right direction (downstairs),
but I fear it's going to generate a good bit of noise..

Daox 10-20-13 02:35 PM

Cool stuff. Have you monitored attic temps in the winter? I haven't done it religiously, but I do know it won't get up to 60F in winter. Its pretty well ventilated though.

Xringer 10-21-13 10:14 AM

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Originally Posted by Daox (Post 32529)
Cool stuff. Have you monitored attic temps in the winter? I haven't done it religiously, but I do know it won't get up to 60F in winter. Its pretty well ventilated though.

I'll have to go back and look at some of my postings.. But I think the 70s
might be pretty common during the mild parts of the winter.

It got down into the 30s last night, so it took a while to warm up this morning.
(I love these charts and need to make my own from the CAI data)!

Right now, at 11AM. ----------- At 14:42
61.8 F in the basement----------62.7
58.4 F outdoors -----------------63.4
70.7 F in the attic Peak----------95.1

I had the blower set to come on at 65 F(in attic), and it came on around 10AM.

Not doing much good now, but when I get all the attic hardware installed,
it will be sucking down that warm peak air.. :D

My plan is to program a differential function into the CAI board.
If the RH and time of day are good, it will pump warm air down from
the attic, anytime the attic air is warmer than the basement air..

In the dead of winter, I may have to change to program, so that I can
pump down some no-so-warm air, cool down the basement a little,
pause and let the basement come back up(GeoSlab) to normal and repeat..
Hopefully, I won't have to resort to using the cold air flush.. :eek:

Daox 10-21-13 10:19 AM

Well, its still better than sucking in ambient air not matter what, which is what your fans were doing before. Even if its not-so-warm, its also not-as-cold-as-outside. :)

Xringer 10-21-13 04:17 PM

data logger
I joined an interesting forum a while back.. Today I looked for a CAI data logger and found one!

CAI WebControl Logger [Software] - Page 11 - CAI WebControl -

The download link is Weatherbyrifler - Downloads Area - Exe Filer - CAI WebControl Logger v1.4.7

I'll be checking this out, to see how it works with OpenOffice..

So far, it looks very interesting.. :D

Xringer 10-24-13 07:35 PM

Attic blower installed
Today I took data, while I waited for the UPS guy.. (He came at 5:41 P.M.)
The attic temp got into the high 70s, since it was pretty cloudy today..
Outdoors stayed in the low 50s all day.. The basement stayed pretty stable.

After supper, I installed the new fan and dryer duct in the attic..
Dang thing sounds like a jet engine! But, it's not too loud when the doors and pull-down stairs are closed.

I put a filter 'sock' over the warm air in-take. Hope it stops some of the larger particles.

The forecast for tomorrow is cooler, but mostly sunny.. :)
I'll try to get the data logger running before the attic heats up,
and see how well this rig is going to work on a mild day..

Xringer 10-25-13 06:28 PM

Solar? Too many clouds!
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The forecast didn't work out.. Maybe tomorrow we can get some real sun..

Pretty cool and cloudy for most of the day. The PV heated water tank climbed in unison with the attic.
But, it didn't cool off as fast. Again, the basement temp was pretty flat.
I was able to tweak the program a bit and got the fans turning off & on nicely.
I used a setpoint with only a 3 deg differential (warmer in the attic)
and tried a 5 deg diff later in the afternoon. I can see that a higher
number is going to be needed.. Maybe 8 or 10 degs F.
Air that is just slightly warmer than the basement has very little impact.
I could feel very little warmth down there. Barely noticeable.

I can't wait to see 80s or 90s in the attic. That's going to warm up the basement stairs, at least. :rolleyes:

I did some measurements of the slab.. It's pretty uniformly cold <60F.
Warming up the air in the basement looks like an uphill battle..

I've had the A7 unplugged, for a few days, and with little sun to heat the
water tank, it's been dropping a lot. But, it's a good indicator of sunshine. :)

One thing surprised me. Even when the sun was dim, sucking the air
out of the attic, didn't really drop the temperature up there very much..
I had expected to see a pretty rapid drop in air temp (in the peak area)
when the blower started moving 200cfm downstairs..

But, that wasn't the case. The temp drop was pretty slow.
I think the main reason it dropped below the set-point,
was due to the lack of solar..

Yesterday, early in the morning, when the sun first hits the roof, I was out there with my IR scanner.
I measured 85F on the singles. But, when I went inside and scanned the
attic boards near the peak, they were only in the 50s..
This lag-time (plus the observation above) leads me to think
my roof is a pretty good thermal mass.

~~~~~~~Edit 9:43 AM
It's sunny now, but it looks like a ton of clouds are rolling in.. :(

Daox 10-26-13 11:11 AM


Originally Posted by Xringer (Post 32626)
One thing surprised me. Even when the sun was dim, sucking the air
out of the attic, didn't really drop the temperature up there very much..
I had expected to see a pretty rapid drop in air temp (in the peak area)
when the blower started moving 200cfm downstairs..

But, that wasn't the case. The temp drop was pretty slow.
I think the main reason it dropped below the set-point,
was due to the lack of solar..

Yep, I've found this to be the case too. This is why I've recommended and plan on adding additional fans to harvest more heat. I've had my fans going after 10pm sometimes...

Piwoslaw 10-26-13 02:07 PM

The good thing about using attic heat to warm up the basement is that you can use cooler air than for heating the house, so there are more days during the year when you can harvest this lower grade heat. And a warmer basement = warmer floor above it.

Xringer, iirc you mentioned that you pump warm air from the attic into the basement, and at the same time pump cooler air from from the basement floor outdoors. Why not pump the basement air back into the attic, since it is (most likely) warmer than the outdoor air that is being sucked into the attic?

Xringer 10-26-13 03:11 PM

Hi Guys!
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Thanks, I'm going to change the system off time to 10PM!! :)
And we shall see what happens..


I agree about pumping in some not-so-warm air.
If it's warmer than my basement, it's welcome.
I might just program the set-point for basement temp+5 deg F.

My wife and I have already noticed it's nicer in the basement today.
We can feel the difference. The log shows a 4 deg F gain,
but a lot of that is due to heat leakage from the hotwater tank(PV gain) and my wife ran the dryer.. :o
Bad data day again! One of these days, we'll get a solid solar day!

The air the I'm pumping outdoors, is coming right off the floor (cold concrete slab)
and is slightly contaminated with a heavy gas called Radon.. :eek:
So, recycling it isn't the cards.. I'm pretty sure that a really good filter
would be needed to clean it up.

Got a little bug in my logging for some reason..

Here's the plot for the day..
Got some hot water in the tank and a little hot air in the basement.. :)

Xringer 10-27-13 06:51 PM

Sunday wasn't too cloudy..
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But you can see on this temperature plot, a bunch of little peaks in temperature,
between 8AM and 4PM.. When the clouds come, the air temp drops.

Temperatures displayed in F, without a decimal point. (Raw CAI data).
Today is the first time we have seen 80F in the attic, with the new setup.
I'm pleased to say we saw at least 2 deg F air temp increase in most areas of the basement.

Outdoor temp was pretty flat all day. Even with all the clouds, the water tank warmed right up nicely.

I might have to work tomorrow, so there may not be much data taken..

Daox 10-28-13 10:31 AM

Cool, looks like it is working out. Do you have any logs from the night to see how the temperature drops off?

Exeric 10-28-13 12:44 PM

XRinger, it sounds like things are working out for you. I'm a bit jealous of your peak temp differential between attic and outside temps on your latest measurement. 34 degrees is pretty good! I'm finding that the peak differentials that I recorded for those same parameters has gone down quite a bit from summer. Now its usually between 30 and 35 degrees, which isn't what I'd hoped.

Of course, my situation is different in that I still don't have ceilings yet! No insulation up there either. Plus, biggest of all, I still haven't closed the roof vent because I'm trying to keep a constant baseline for measurement.

Do you have a roof vent that is open? Inquiring minds want to know. If you do, then I'm definitely jealous.:p

Xringer 10-28-13 12:57 PM

You can see the west (left) side attic vent near the peak.
There is another vent on the east side, above the #1 Sanyo outdoor unit.
There is also a ridge vent along the top of the peak.. A lot of the heat escapes there.

The attic intake (for the blower) is very near the center of the attic..

I have not paid any attention to the late night attic temp, I think it depends on how fast and far it drops..

Early in the AM, the attic has been about 1 degree warmer than the outdoors..
Must be leakage from the Sanyos and the difference in altitude of the sensors.

Started the logger at 10:34 this morning. Came back and it was still working!
According to the math for a 200cfm air flow, in 30 minutes, you can move 6,000 cubic feet of air!
So, all the air in my basement is being changed twice an hour.. :rolleyes:

We discovered that holding onto the hardwood banister on the way downstairs,
we can easily 'feel' the temperature change, as you near the middle steps.
Up top, the banister feels warm, but as you decent to the point where
the angled overhead meets the basement ceiling, the wooden rail becomes quite cold, to the touch.
That's the point where the warm air slides into the basement, along the basement ceiling.

Xringer 10-28-13 10:14 PM

12 hours of data on a partly sunny day
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Hot part of the day in the attic 80.2 @ 01:52:16 PM

The setpoint is 66F. With 200cfm being sucked out, I expected to see
a little negative jog on the plot.. But, it's not there in the AM
and might be there a bit in the afternoon (when the temp dropped below 66F).

Right now, it's 11:12PM and it's 42.4 F outdoors and 44.0 F in the attic..

PS: When the DHW hit 105F, my wife washed her hair..

Xringer 10-29-13 10:36 AM

Mostly sunny day at 11:30 and the fans aren't on yet..
The roof is hot, the inside roof planks are warming up..
But, the attic peak sensor is only showing 61.8 (outdoors is 45.5).

I looked at the ridge vent with binocs and I could see the heat wave effect.
Inside the attic, I measured the temp of the planks close up..
The lower planks were warm, the middle planks were warmer.
Higher=warmer.. Until the last plank at the peak.. 20 deg colder!
The ridge vent is sucking out the heat! :mad:

Daox 10-29-13 10:45 AM

Yep, I've noticed on windy days the fans stay on for way less time and take a lot longer to start up too. If you could control how much vent is open or something, you could really harvest a lot more heat.

Xringer 10-29-13 11:31 AM

Low pressure
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I don't think my end-vents are effected much by wind, but it's possible that wind
hitting the ridge vent is causing a vacuum effect to suck out the heat.?.
(See drawing pic of garden sprayer).

Theory #2:
I think that my air intake is creating a low-pressure-area a few feet around it.
Air is going to rush to the intake, to fill the vacuum.
But, it's going to take the path of least-resistance.
So, instead of coming in from the end-vent (as I wished for), air is being
sucked in from the outdoor air, (1" above the roof) passing thru the mesh in the ridge vent..
The air being sent down to the basement is a Mix of warm attic air and cold outdoor air..

If Theory #2 is correct, I need a way to block up the ridge vent for about
10 or 15 feet on either side of the air-intake and temp sensor..

I just took some plastic shopping bags up and stuffed them into the slots in the attic peak.
Got 3 or 4 feet blocked off on each side of the intake.. Might help a bit..

Exeric 10-29-13 12:47 PM

Yeah, I've noticed the same thing. When the wind is above 10 mph or so the peak temps in relation to outside air temp never gets to where I expect them to. A gable roof seems like it might be very difficult to work with compare to a hip roof. Hip roofs, like mine, have other disadvantages in that you don't get much laminar flow up the roof sheathing, but it has the big advantage that the air moves up and concentrates in a relatively small area. Big advantage there if you want control it with a damper like the one I installed on my roof.

I've been trying to think about a good way to control that flow in Xringer's roof. That ridge vent seems like a real problem for accumulating heat. So far I haven't thought of a way around that doesn't seem like a bit of a kludge that would be expensive in terms of labor and maybe even materials.

Xringer 10-29-13 01:08 PM

Plastic shopping bag hack looks good..
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I just scanned the exhaust vent and it's warmer than I've ever seen it.
The attic temp was 74.4F and 73.5 air is coming downstairs!
Earlier measurements at the exhaust vent were always just a few degrees
higher than the basement temp.. I need more Plastic shopping bags!! :D

Xringer 10-29-13 05:44 PM

The 'After' data.
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This is the data taken this afternoon, right after blocking up the ridge vent with shopping bags.
Starting at 13:30, I took many IR scanner readings on the attic exhaust vent (as in pic above),
and they were all about one degree F lower than the peak temperature.
For the first time, we could actually feel some real usable heat coming out of the vent. :p

The warm air output stayed steady right up to shut down at 66F.
After the fans turned off, the attic plot line stayed on the same track.
Almost like the fans hadn't been dropping the attic air temp at all.

For about 4 hours, the blowers were moving about 200cfm of warm air into the basement.
Approximately 48,000 cubic feet of warm air!

As you can see from the plot lines, it wasn't too warm today, but the sky was mostly clear.

I just looked at the weather. Next few days are going to be awful..

Xringer 10-29-13 06:57 PM

Cold slab? How to warm it up?
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I think the reason the basement air temperature is changing very little,
is likely due to the coldness of the floor slab. It's about 57deg F everywhere in the basement.
I think it's sucking up the heat like a sponge..

I've been thinking about sticking a sensor in the slab, so I can monitor it's heat.
I'm a little surprised to see the slab so cold, this early in the winter season.
Temperatures this month have been pretty normal.
Nothing that would cause the slab to be extra chilly..

It was 46F on the slab last winter.. (‎February ‎05, ‎2013)
Cold Basement Video by Xringer | Photobucket

That seems a little too cold, and it's got me wondering how much the slab
warmed up over the summer? All summer, it was 65~70F in the basement.

Maybe the ground around the house and under the slab didn't fully recover from last winter?
Back in the good old days, the slab was warmer.. Maybe around 65F this time of year..

I'm thinking about something very weird right now..
The possibility of using this attic air heating system,
to heat my basement during the Summer of 2014..

If we had enough low humidity days, I could run the blowers and easily
heat the basement air to 72~75F, on the summer days..
Unless the slab has ice under it next summer! :eek:

MN Renovator 10-30-13 06:34 AM

"I'm thinking about something very weird right now..
The possibility of using this attic air heating system,
to heat my basement during the Summer of 2014.."

Don't do that. You'll be heating the rest of the house too and need additional cooling as well as bringing high dew point air into a place with cold surface temperatures which will cause condensation and that moisture will migrate upstairs.

"..right after blocking up the ridge vent with shopping bags."
You shouldn't do this either, this will become especially important when snow starts to fall, you'll have ice dam city on your roof. Even without the issue of ice dams, attic ventilation is important for moisture mitigation and by keeping the air stagnant in the attic you are increasing your risk for mold and wood rot up there.

We ventilate attics for a reason.

Xringer 10-30-13 07:34 AM

I would only heat the basement on "low humidity days" per above.
My RH sensor tells the CAI when it's okay to run the blowers.

I'm not worried about too much heat from the basement over-heating
the living area, since we never cool the house below about 74F anyways.
The 'heating' temp of the basement could be set to match the temp of the living area.

The ridge vent is new. The roofer sawed a ragged slot down the peak and put on the vent cap..
I didn't really want it, but somehow ended up with it anyways. Jacked up the cost? Yeah!

Since this house doesn't have any ventilation soffits under the gutters,
(Except on the den, a new addition) we are used to getting ice dams
when the conditions are there. Snow and rain, followed by rain or melting
followed by low temps.
We have heating wires installed on the north side roof, where the sun is blocked
during winter's low sun angles.

Exeric 10-30-13 01:51 PM

Xringer, if the attic wasn't too wet before the ridge vent was installed then the side vents must have been sufficient. I wouldn't worry too much about that. But I would agree with MN that heating the basement in summer might not be the thing to do.

Have you considered insulating the basement? You probably don't want to do that but it's probably the most efficient way to fix the problem.

Xringer 10-30-13 04:02 PM

It's been dry since August 1973
We store Christmas stuff, luggage and other stuff up there and never had any problem with dampness.
Now that we are getting old, I'll have to clean all that stuff out, while I'm still able.
The basement is where we have all the dampness.

In the summer, I'll try leaving the ventilation system in heating mode,
so both warm (above 66F) & hot (dry) air is pumped into the basement.

That will keep the air moving in both the attic and the basement.
Using the CAI program, I can limit how warm the basement gets,
just by shutting off the attic's blower. Or both blowers.

It if starts up at 66F in the mornings, a good bit of air can be moved
before the attic heats up to the 100F plus range.
In the summer, I think it would be nice to have the basement in the mid 70s.

If the system tries to pump down 120F air, I can just pull out the shopping bags,
to start pulling in a mixture of hot and outdoor air.. :cool:

Xringer 11-01-13 08:19 PM

Used the A7 today..
It was rainy, windy and overcast all day. But there was a short burst of dim sunshine. Didn't last long.

The orange plot (DHW) can be seen going up, all the time the A7 was running.
The blue trace (basement) does the invert of the water temp..
The A7 really chills that part of that basement..
Once the A7 shuts off, you can see the warm air starts heating up the basment
fairly fast..

At "A little sun", the water temp climbed because of PV heating..
The sun was so weak, I never expected to see a 'bump'..

As far as I can tell, the RH sensor is reading 10 to 12% higher than the 'real' RH.
I'm not 100% sure, but when I compare my RH with the local Underground Weather and the site,
my RH sensor reads 10 to12% too high during very damp weather.

So, in order to get a RH setpoint of 70%, I have to use 80% as my setpoint.

Xringer 11-02-13 07:37 PM

10 hours of data
My wife ran the dryer twice today. I can see the jump in RH and outdoor temp.
We took a bike ride to Bedford, and after we got back she did the second wash.
The drop in hot water temp on wash number #2 proceeds the RH spike from the dryer exhaust.

When we returned from our bike ride, the attic temp was almost 90F.
The basement stairs was a very warm 89.9 on the IR scanner.

Basement temp readings seem to be affected by the dryer.
I noticed the basement temps jumped with the humid air blast from the dryer.
The door of the dryer scanned at 90F.. That door is only 8 feet from the sensor.

Lesson learned:
Don't install sensors close to heat (or humid) sources.

It was a pretty mild day, but we had good solar. Best 'heating' of the basement so far.

jeff5may 11-03-13 09:47 AM

Looks like you could stand to run some of that hot attic air straight into the airtap. It would definitely boost the cop of the unit, while offsetting some of the cooling of basement air. Literally moving the hot attic air into your water heater at high efficiency. Maybe a couple of lines in the plc code to run some warmish, more humid air towards the unit for more latent/less sensible heat removal? Hot, humid attic air turns to cold condensate down the drain rather than cold, dry basement air...

AC_Hacker 11-03-13 10:00 AM


Originally Posted by Xringer (Post 32750)
...proceeds the RH spike from the dryer exhaust. I noticed the basement temps jumped with the humid air blast from the dryer.

So, you are venting the moist dryer exhaust directly into the basement?


Xringer 11-03-13 11:33 AM


Originally Posted by jeff5may (Post 32751)
Looks like you could stand to run some of that hot attic air straight into the airtap. It would definitely boost the cop of the unit, while offsetting some of the cooling of basement air. Literally moving the hot attic air into your water heater at high efficiency. Maybe a couple of lines in the plc code to run some warmish, more humid air towards the unit for more latent/less sensible heat removal? Hot, humid attic air turns to cold condensate down the drain rather than cold, dry basement air...

The reason I'm trying to move the hot air down the basement stairs,
is because I don't have any good place to install duct work from
the attic down to the basement. So, this setup is a compromise,
since a little heat sent to basement is better than nothing.

The humidity sensor checks the outdoor RH before turning on the blowers.
So, we never pull much damp air into the house.
Maybe a little leftover damp air in the attic, right after the outdoor humidity drops.

Xringer 11-03-13 11:43 AM

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Originally Posted by AC_Hacker (Post 32752)
So, you are venting the moist dryer exhaust directly into the basement?


Nope, it goes out a vent on the north side of the basement.
The outdoor sensor pod is located about 5 feet east of the exhaust vent.
So, when the wind is blowing from the west, the warm moist air flows
along the back of the foundation, right to the sensors! :o
So, I've got to move sensor pod to a better location.

Just got done installing the new CAI board this morning,
and so far it's working okay. Just had to change a few lines of code.
The X10 commands have changed with the new version firmware.

Here's a screen shot of the new status page..

jeff5may 11-03-13 12:16 PM

I know y'all will hate this, but this is what I did in my last (rental) house:

I ran the airflow backwards thru the (crappy) central air system from upstairs during the winter. There was one 5" supply duct for the whole (semi) finished attic, which did not supply enough heating or cooling upstairs in any conditions.

So I grabbed a squirrel-cage blower, turned it on low speed, and set it directly on the lone register upstairs. I had my window unit heat pump up there, set on auto, to regulate the upstairs as its own zone. It ended up saving me like $1000+ last winter in heating bills. Basically, the blower was heating and cooling the downstairs from above, as well as tempering the crawl space through the leaks in the ductwork.

In this new (rental) house, I substitute an under-vented, partially finished basement for a second story. The solution here: the same (hacked) window unit does its thing downstairs now, plus I opened up the return air plenum and run the central system fan on low when it needs it (playing with cycle timer settings now).

Xringer 11-03-13 02:40 PM

Frequency Counter?
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My daughter's house has a messed up central heating-cooling system.
It was the second system installed in the house, and uses much of the old junk ducts..
Hardly any cooling on the second floor.. But, in the winter, the heat comes up the stair case..
She needs a couple of Mini-splits! :p

PM Update:

I moved the outdoor sensor pod away from the house.
It should not be effected by the dyer's exhaust, in it's new location. (I hope)!
I also removed the 'spare' outdoor heat sensor, from the pod. DS18B20

I moved the basement heat sensor away from the A7 and dyer..
It's now near the base of the basement stairs, about 5 feet up off the slab.
Now, it won't be directly affected by the IR heat coming off the water tank or the dryer. :D
This should give me a much better picture of air flow from the attic. (being near the stairs).

The new CAI board seems to be working okay, a bit of late day sun came out and fired up the blowers.. :)

Tomorrow's weather promises some good logging..

The new layout:

Xringer 11-04-13 04:56 PM

Changed program today
The sun was out and the attic was warming up pretty well, but the program
was waiting until the attic hit 65F.. That took a while. Seemed like too long..

In the middle of the day, I modified the program to use a floating setpoint.
The new setpoint is updated every 15 minutes and uses the basement temp+3 deg.
So, if the basement has warmed up during the day, or gotten colder (A7 run),
the blowers won't run, unless the basement 3deg F cooler than the attic. :D
Now, don't have to worry about changing the setpoint..
All I need to do now is evaluate that 3deg number.
Should it be 3.5 deg, or 2.0 deg.?.

Xringer 11-04-13 07:52 PM

A picture of explanation
Kinda shows what I've been talking about, in one dimension..
Maybe I should make a video..:rolleyes:

Xringer 11-13-13 06:25 PM

Never got very warm in the attic today..
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The attic hit 64.7F at 13:19 and that was about it..

Xringer 11-15-13 06:53 AM

Back door heat losses?

After looking at the temperature data for the basement during the last week,
and seeing pretty mediocre results, I was somewhat disappointed.
I know it's really hard to heat an uninsulated basement, with a floor slab
that's kinda cool all year round..
But, I want a bit more than a 1 or 2 deg increase in basement air temperature.

So, I'm thinking about replacing the back door (and storm door).
That glass is always cold. It's facing north, so there is no sun coming in,
and just a 1956 32"x80" wooden back door and aluminum storm.
The only good thing about it, is the glass provides a little light during the day.

Not being a door guy, I'll have to study this project a good bit, before
taking it on, or hiring someone to do it.

In the meantime, I've been taking some temperature readings. That door is cold 24/7!
I think it's effect on my warm-attic-air experiment is much larger than expected.

So, today I'll be taking data with a new factor added.
Last night, I covered the top (glass) part of the door with clear plastic.
Also went outside and covered the glass part with a second coat of plastic.
For today, the plastic isn't sealed around the edges very well, just a few push-pins.
But if today's data looks any better, I'm on the right track.. :)

Xringer 11-18-13 10:07 PM

Not so good..
1 Attachment(s)
Good solar day. Warm.. We went for a 15 mile bike ride and had lunch outdoors.

The basement temperature gain was 2.7deg F. Not really that good.
The hotwater gain was excellent.

I'm wondering if this job is too big for 70-80deg F attic air @ 200 CFM.?.
Thinking about doing a little testing with a space heater.
Dump in 4,000 BTUh for a few hours and see what temperature gain we get..

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