Here's some results to the math.

Assumptions
Attic 85 degrees, Basement 62.5 degrees
Difference 22.5 degrees

Output 4860 BTUhr or about 1424 watts of space heater.
...but, this is ONLY when the temperature difference was that big, which wasn't for a very long time.

"70-80deg F attic air @ 200 CFM"
65 degree basement and 80 degree attic air
3240 BTUhr

65 basement and 60 degree attic air...IMHO, don't bother running the fan.

Once your roof has snow on it, its endgame. If the attic is still holding a temperature warmer than your basement once you have a layer of snow on it, you are better off spending some money sealing it up and insulating rather than pumping the warm air that used to be in your house back into the basement.

Right now, the programed setpoint temp(of attic air) for turning on the fans is the basement temp+4 deg F.
In the afternoon, the attic has to be 6 deg F warmer than the basement.

With the current setup, there is never any cold air pumped into the basement.
It's always at least 4 degs warmer than the basement air. It's just not making a dent..

Right now, it's sunny and Temperature Sensors show 58.2 F in the basement and 60.2 F in the attic.
The fans aren't on yet.

What I find interesting about the plots, is the absents of effect on the attic temperatures.
I expected to see a drop in attic air temperature, shortly after the fans came on.
This leads me to think there is a lot more warm air available in the attic,
than my 200 CFM fans are pulling down..

I had this idea, the fans would be turning off and on as the attic cools, and re-warms.
But that never happens. Once the sun has been gone a while, it shuts down.

There is residual heat in the attic for hours, depending on the outdoor temps,
it's not long before the attic temp become very close to outdoor temp.
(You can see the plot lines merge on some of the charts).
I don't see much to indicate more attic insulation is needed.
Of course it would help, but the amount of gain for labor required, is questionable.

I understand what snow cover does, I've had a sensor in the attic for years.
During the winter, I still might want to bring in a shot of fresh dry air,
even if it's cold up there.
Since I have a feeling the basement will recover fairly fast..
I may interface one of my Radon detectors into the CAI controller..
That cold air shot will cost me BTUs, but it will make the basement safer.

I've said it multiple times. :p If I am going to modify my system (which already has 2 fans), I'd add another fan.

I mounted a Solar Sheet air to air panal on the side of my house thinking it would offset the cold from my ASHP water heater. Even though it blows 100 degrees sometimes it does not seem to make a dent in the basement temp. My concrete walls are not insulated, I think they suck up the heat. My basement is staying between 56 - 58.

Mine seems to stay very near the ground water temperature.
Seems like the water table is just a couple of feet under my slab.

I have noticed the basement is a bit more comfortable after the fans have been on.
The warm attic air takes a bit of the chill out of the air.
Maybe the attic air will take some of the sting out of running the A7.
But, when the sun is out, the PV usually makes any A7 run unnecessary.

The lack of insulation makes warming a very hard task..

My system is already a bit too loud. Another fan isn't going to happen.

I may have to be happy with what I've got. We'll see if we can get
some air flow this winter and not bring in a lot of cold air..

I think the slab got down to about 49F last winter..
So far this year, it's at 55 to 60F. And I have a hunch, if I bring in
some 35 F air, it's going to very little effect on the basement air.
It's going to recover it's 55-60 temperature within a short time.

It sounds like you have 2 things working against you xringer. The first is that your basement and water heater may be acting as heat sinks. The water heater for sure and the basement maybe. The other thing is the attic as source of heat might be insufficient. I'm not saying these things are facts but they are the most important to look into. The need for a lot of fan power seems to me to be a symptom and not a cause of the problems.

The problem with the attic as it is that the heat is diluted by the large volume of the attic. You only have so much radiation energy entering the attic. It might not even be that much in Massachusetts. If you don't restrict that radiation energy to as small a volume as you can reasonably do then the temperature will be lower and the volume of air that needs to be moved with a fan is much higher.

For example you might have 1000 cubic feet of air that is heated by the sun in the attic now. If you restricted that to 50 cubic feet through some kind of insulation then you would need a fan that moves 50/1000 or 1/20th the amount of air down to your basement. That is because 19/20ths of that air would now be cold and not needed to be blown down to your basement.

I just threw those numbers out. So think of it as a principle rather than a respresentative model.

So far this season, we've had enough sun to provide 90% of our hotwater,
from the 1,300 Watts of PV connected to the water tank's elements.
So, the A7 heat pump isn't a factor so far.
However, there is a little thermal heating in the area of the tank, due to heat losses.

The basement slab is around 65F most of the summer and 55 to 60F during most of the winter.
The upper part the basement walls get colder as the weather gets colder.
40deg F wouldn't be unusual.

My rough calculations for air flow say that all the basement air will be changed about twice an hour.
(when the fans are running).

After looking at the attic temperature plot lines for a few days,
I can't see any change when fans are turned on, or off.
That has to mean the attic has a lot more hot air available, than I'm using.
Otherwise, the attic temperature would drop within minutes of turning on the fans..

It sure seems like I need bigger fans.. ;) Not gonna happen!


I've been thinking this over, and I'm starting to understand what it takes to heat up the basement.
I remember back in the days of cheap oil, we used to turn on the basement
baseboard heat during the winter.. I had a TV down there.
One thing I recall was how fast the basement play room would cool down,
after the heat was turned back down to 50F.. It was almost instant.

I was thinking your water heater used heat pump technology, which would transfer heat from the room to the water. Did you change over to a regular electric water heater run from solar?

Edit: Never mind. I figured it out.

Strange days
 

Yeah, it's a strange hotwater heater. :)
During good weather, most of our hotwater comes from the PV arrays.
During bad weather or heavy hotwater use, the A7 heat pump comes on too.
Nowadays, the A7 might get another form of solar assist, from the attic air!

Got an off-on cycle!
 

Cool and sunny today..

http://ecorenovator.org/forum/attach...1&d=1384982092

I didn't understand what happened, since I didn't notice any clouds coming over.
Then, I took a close look at the outdoor temperature plot.
When it got up to 35F, it didn't keep climbing. It went down a bit and stayed flat for a while.
That's when the setpoint kicked in and shut down the fans for a while (15 minutes cycle).
The basement temperature gain was only 1.1F during the fan run.. Better than nothing.. :o

Sunny, but cold and windy..
 

No attic hot air to day.. The outdoor temperature was too low
and the wind seemed to be keeping the roof cool.
Outdoor scan of the roof after lunch, showed 65deg F.
Inside the attic stayed too cold for fan activation.

I just looked again and the Basement has finally changed, it's now 54.5F,
after all day long at 54.6F..

Check out that Outdoor temperature! Not your average day.. Chilly!

Here we are at 16 hours into the day and have used 17.4 kWh to heat the house..
We did get a bit of solar in the south facing windows.. :)

http://ecorenovator.org/forum/attach...1&d=1385326450

Very cold and sunny
 

After we got back from errands and lunch, we noticed the basement ventilation was running..

It was 25F outside! But, there wasn't any snow on the roof.
I turned on the logging and captured the tail-end of the fan run..

http://ecorenovator.org/forum/attach...1&d=1386886324

I think the total run time was about an hour.. Not much, but it did put
a little fresh air down in the basement.

At 17:17, it's 35.4 F in the attic, and dropping rapidly..

Not sure, but the hot water tank might be loosing heat a little faster
when it's only about 50F in the basement.
(Or, my wife was washing something in hotwater).. :confused:
Tomorrow's forecast is for Partly Cloudy & Mostly Cloudy.
After that, it's looking like a weekend of snow and cold.. :(
I'll be running the A7 for sure again..

Could add more wrap to your water heater to combat the cool environment it winters in.

That was a consideration when I made the install..
http://ecorenovator.org/forum/22725-post13.html

I'll revisit the idea..

that is very strange that the water tank manufacturer says - Do not add insulation , it will do no good - Something fishy in Denmark.
I know you know that
heat storage is very depending on the insulating factor of its enclosure the very nature of its function indicates more is always better. :)

They may have measured or calculated, and found there would be very little heat loss prevention.

My main sticking point is covering up the two access panels.
Making my power connections and heat sensors inaccessible.
So, I would have to use a thermal wrap with large holes in it. :o

The other thing, is water leaks. If a small water leak occurs
in a covered area, or an area that isn't easily visible, it can go for weeks undetected.
I had that problem on a old HS Tarm boiler and it ended up costing me a lot of money..
http://i46.photobucket.com/albums/f1...L/DSCF0149.jpg
A large plate was fabricated and used to replace the rusted out area.
It had been leaking for years, behind a steel cover and insulation.
It never over-flowed onto the floor. So, it was never seen,
until the damage was done..

I just turned my water heater down rather then wrap it.
Turning it down really cuts energy consumption, one layer of wrap may not be to effective any ways..

If I'm going to spent more money on more insulation, it's going into the attic.. :)
Since I can now log attic temps and outdoor temps, I can see there is a lot of waste up there..
I'm getting a new thermal leak detector as my Ecorenovator prize..
It's first task will be up in the attic..

Solar shower surprize!
 

We've been using solar for hotwater most of the time and not running the A7.

http://i46.photobucket.com/albums/f1...ps2dae2e6a.jpg
Today, we had a good work out moving snow around. Afterwards, it was shower time.

After taking our showers, I noticed something odd..
Our water tank temp was down to 73F !!
http://i46.photobucket.com/albums/f1...ps2b4c1251.jpg
(Note the attic temp.. It's flat because the roof is under a few inches of snow).


How can that be? The water has to be hot! My wife would have screamed.. :D
I checked the HW in the kitchen sink.. Still over 100F.. :confused:
But, the fish tank temp display on the tank said 21C!

I figured a pipe was leaking cold water into the senor area..
So, I had to inspect both sensors.. Nothing odd found,
but the tank didn't feel warm.. So, the sensors were right.?.


After a while, it came to me. The hot water we were using was from the Top of the tank.
We didn't use it all. But enough to allow the cold water to rise up to
the sensors, which are installed near the top of the tank..

http://contractormag.com/site-files/...ctr1301p06.gif

That will be a effective tool, you can find the cold spots from the inside or hot spots from the outside.

Is it a thermal Imagery or IR technology ?

It's the prize I won.. I was randomly lucky again..

Black & Decker Tools | Thermal Leak Detector TLD100

It's got some good reviews on Amazon Amazon.com: Black & Decker TLD100 Thermal Leak Detector: Camera & Photo

It looks like an IR pistol with some extra 'leak detector' functionality..
This should make it a lot easier to survey the hot spots up in the attic..
I know where some are already.. Just by watching the snow melt..

here it is...

http://www.youtube.com/watch?v=xpifuiVpv2w

Looks pretty neat. I've got some new 9V batteries waiting for it.. :)

HA, HA. I've got one! It works well. You just point it when you turn it on at something who's temperature your interested in. The first thing you point it at calibrates it as a reference temperature and also gives you a readout in F or C.

If you point it somewhere else with a different temperature the light showing the target changes from green to either red or blue, depending on if the new temp is below or above the reference temp from where you first pointed it. It also gives the numerical temperature just like a regular IR detector.

There is a handy switch that allows you to alter the trigger point from the reference temperature at either 1, 5, or 10 degrees to turn on the blue or red light. When I bought the thing I was just looking for a regular IR detector but this is better and very intuitive. (Also no more expensive.)

Thanks!
 

Sounds pretty good!

What I don't like about using my regular IR detector up in the attic,
is the concentration needed to walk around up there (only a small area has flooring)
and try to take readings, by watching the temperature display bounce up and down..

With the TLD100, my foot sticking out of a hole in the living-room ceiling will be a lot less likely..
;)

I guess it's funny when you're standing down stairs..

Foot Through Ceiling | Flickr - Photo Sharing!

http://i.imgur.com/AhPR6pS.jpg

http://farm4.static.flickr.com/3649/...55b07a34_o.jpg

I got another X10 error this morning
 

It was 38F in the attic..
The two fans came on, when the heat should have come on. (Both fans use the same device code, 7)

In binary, the fan device is 0111 and the heat device is 0101 ..

Seems like a burst of RF noise or AC line noise in the middle of the byte, could confuse the receiver.. A single bad bit..

I would change the house code on the fans, but that would make them too hard to control them using the handheld RF remote control.

Maybe I just need to make the device bytes more dissimilar.
My three device codes in use now, are 5, 6 & 7. 0101, 0110 & 0111.
I'll change them to 0001, 1000 & 1111 and see if that makes them noise proof..

If those device codes still get errors, I'll try using three different house codes too.

FAN_ON:
X10 2 7 1
RET

HEAT_ON:
X10 2 5 1
RET

etc.

~~~~ From PLC manual~~~~
X10 RF function is supported in the PLC programming also.
In PLC programming, PLC command is in the format:
X10 H U C
Where H is house code from 0-F, U is unit code, also from 0-F; C is one of following
four commands:
0 – Off
1 – On
2 – Bright
3 – Dim
If the X10 function enabled, TTL7 and TTL8 should not be used for controlling other
devices. Please note PLC logic uses 0-15 or 0-0xF for code, web GUI only use 0-F

Solar has been very good to me.. :)
 

Lately, Solar PV has been doing around 80% of our winter hot water heating..

http://ecorenovator.org/forum/attach...1&d=1391398349

Saturday was pretty mild, and it was sunny. But, even on some really cold
days, the fans are coming on and driving some warm dry air into the basement.

Even today(Sunday), with a lot of clouds around,(some rain in the afternoon)
the attic still got warmer than the living room.

We keep the LR at 21C (69.8F) and the Den at 20C nowadays.
Those settings seem to balance out the kWh used by the two Sanyo units.
Today, the Den used 7.2 and the LR (main house) used 8.0 kWh. (~$2.75)

That is pretty cool that its working for you even in the middle of winter. I looked at my attic temp the other day when it was sunny out, it only got up to about 40F.

No heat flow! It just keeps snowing!
 

We get great solar PV, but our attic stays too cold..
For days after it snows, the air up there is too cold to use.

Right now, it's 40.4F in the peak of the attic, so it's melting, very slowly.. :mad:

http://ecorenovator.org/forum/attach...1&d=1392052059

Maybe I should put about 100' of melt-wire up there.?.
To save power, I could rig it so I could switch in the 800W PV array.
The 800w PV array is almost self-cleaning. 1/2" of overnight snow melted fast in the morning sun.

If I could get 50 to 100 sq feet of clear roof in the middle, that would help a lot.

Xringer, it sounds like you're living the Vida Loca in the basement, wearing Hawaiian shirts and listening to Jimmy Buffet cd's - or not. It might be time to accept that your climate is never going provide enough heat on a consistent basis in the attic to provide heat to your basement. Just a thought, though I might be out of line here. Let me know if I am.:D

Too much snow on th roof and more on the way!
 

You're right. It's terrible when the roof is covered with snow.
For some reason, snow reflects the sun beams right back into outer space.

But, we do have some days when it's sunny and the system turns on..
Doesn't supply a large amount of BTUs, but it moves out the stale air and deadly Radon gas.. :eek:
Since it only runs when the humidity is low, it helps keep the basement dry.

Luckily the radon level is staying low. It will jump up when the melting starts
and water table becomes active.

More snow on the way.. And of course it will be preceded by more Zero weather..
Woburn February Weather 2014 - AccuWeather Forecast for MA 01801
Maybe 8 days of sun before March.. :(

I watched it dropping last night and couldn't believe how low those Sanyos can go.. Still cranking out heat when I crashed at 1:45AM..


I was wondering why my temp sensor reported 12.2F and just down the street it was 4.8F :confused:
I'm pretty sure radiated heat from the Den is warming the sensor pod..
Need more insulation under there..

http://ecorenovator.org/forum/attach...1&d=1392161114
The Sanyos were still working at 12.2F, which might have actually been closer to 4.8F !

So, early this morning, I moved the outdoor sensor a few more feet away from the house and tonight it reads 18.3F degrees,
which is very close to the 18.0F at the weather station down the street.

Gonna be cold again tonight. Might be burning oil by midnight..
2- 3- 4- 5- 6- 7- 8- 9- AM
7° 7° 5° 2° 0° 1° 5° 10°

Running good today..
 

Mostly overcast, but still warming up the attic. It's 14 degs warmer than the basement.
It actually takes a little of the 'chill' out of the basement air.. :)

Temperature Sensors
50.9 F Basement
35.6 F Outdoors
64.9 F Attic

The Radon is up a little, and these warm attic days will bring it down..
http://maps.wunderground.com/data/64...ne_vi_anim.gif

Getting some very cold nights here lately
 

but on these bright sunny days, we are getting 5 or 6 hours of good heating from the attic air.

Last night, it was very cold, but this morning it warmed up fast.
The back-up space heat was on half the night.
The Sanyos were back online at 7:20AM. They were turned off at 10AM, due to solar gain.

http://ecorenovator.org/forum/attach...1&d=1394208743

Without snow on the northern roof, attic temp climbs quickly.
I changed the software setpoint to Basement Temp+5 deg F.
(Attic must be 5 deg warmer than basement to start ventilation blowers)


Current Temperature Sensors show:

50.7 F Basement (Basement floor is 42.1 F, away from oil burner area).
64.9 F Attic
150.0 F Solar PV water tank :cool:

It's warmer in the basement during the day (while blowers are running)
and the radon levels are in the green. :D

Acttic is really starting to warm up!
 

http://ecorenovator.org/forum/attach...1&d=1394387617

It's a dry 40 degrees F outside this afternoon, and with the snow off the northside roofs,
we are seeing some nice attic heat, for most of the daylight hours.

In order to keep the fans from running for the whole day, I'm moving up the setpoint a little bit..
Now, it's set to run the blowers when the attic is 10deg F hotter than the basement..

The PV->DHW tank has been working very well lately. We rarely hear the A7 ASHP come on..
It has been hitting 150F almost every sunny afternoon..

Xringer, I like your thread, you'r pretty high Tech with the data logging.
I enjoy reading your posts on numerous other threads.

I'm thinking of doing similar thing in my next house I'm designing / building someday.

Hole is dug for basement, with no trees to shade until very late in PM, dark green steel roof 9:12 pitch, about 1200 ft2 faces South.

Location:
80813
Teller County Colorado
Zone 5/B dry
Design temp 2* F
AFI = 2500
Mean Annual Temp. 40* F
HDD 6415
Lat = 38.8*
Altitude 8,800'
Very good Solar many clear Winter days, lots of UV, I can get a sunburn in 30 min. in Winter.

I will attach a quick drawing of mini-attic area below 48' long ridge vent.

Roof is vented on underside of roof sheathing & above R51 insulation.
The vented air will flow into this mini-attic before exit out full length ridge vent.

My question is: do you think this is worth doing?

BBP

http://ecorenovator.org/forum/attach...1&d=1395525348

BBP

Wow, I just saw a great place to live.. :)
3011 Teller County Road 1, Cripple Creek, CO 80813 - Zillow

1200 sqft of south facing roof?? The very first thing I would be thinking about is PV panels!
Have you given PV any consideration?

The problem I have with snow and lack of sunny days most of the heating season,
makes me reluctant to say what I've done helps with the heating bill..
Mostly the impact is on the Radon in the basement.

However, this is my first 'spring' with the system in place, and so far I like it.
Since the basement is uninsulated, I'm pleased to see the 49F move up to 52F in a partly sunny afternoon.

Even today, when it was mostly cloudy (but got into the low 50s), we had the blower running a few hours. And, that's with the differential setpoint at 15deg F..

One other thing I noticed today. Since the A7 hotwater heater in the basement was really
pulling the basement air temp down, the warm attic air worked very well,
in counteracting the cold air coming out of the A7 ASHP..
Within an hour after the A7 shut down, the basement temp was recovered.

One of these days, (in May?) it's going to start warming up the basement like crazy.
I hope! And I'll have to add a top limit to basement temp.. :)
Of course, that might be wishful thinking on my part..

My lot is about 2-3 miles South of Florissant Fosil Bed park & 1 mile West off Teller Co 1

Same redish gravel, DG as we call it, Decomposed Granite (high Radon). That listing says Not For Sale?

They call this area a bananna belt, they don't know what they are talkin about because banannas will not grow here. hehe

Yes, PV solar on that roof would work great! but I won't put a bunch of holes in my new Decra shake look steel shingles.

Looking into HD hangers that go on before steel roofing.

So it would be pretty easy to build in the tube, backdraft damper, & pump during construction, but with my ridge vent it may not do much?

BTW, you shouldn't obstruct your gable end vents, they usually barely do the job of removing moisture in Winter.

Radon abatement can involve positive air pressure into basement.

BBP

My end vents are wide open and always have been.
http://i46.photobucket.com/albums/f1...0slot/peak.jpg

I do have the new ridge vent obstructed about 3 or 4 feet on either side of the air intake in the peak..
Otherwise, I end up pulling cold outdoor air into the basement.. :(


If you cover your roof with PV panels, you won't be getting much direct solar heating.
But the bottom side of PVs get really hot, so there will be considerable radiant heat to the roofing.

I've studied Radon abatement a bit, and I've come to the conclusion that
positive air pressure to the slab can't work in this house,
without replacing the entire slab with a new one. It's got way too much damage.

Besides, I've discovered that my radon levels can be kept low by
relatively small amount of fresh air ventilation.
Radon abatement has been very successful, so far.