[Outcast_Searcher]

I'm finding this thread fascinating reading. You obviously have folks here interested in energy and energy conservation. You obviously have folks who are "handy" and have done stuff to their house themselves.

Also the concept is simple. And yet, you have wildly differing theories. (I am a new homeowner (former apartment dweller), am NOT handy and cannot add any information to thisdiscussion - sorry).

I WOULD think though that there SHOULD be some good objective material in quality home construction / maintenance books and/or the library and/or on the internet **IF** you can figure out where to look and which advice to trust.

....

I wonder exactly the opposite, and plan on experimenting with that this summer. I am in my parents' well-built 55 year old house with a crudely finished half basement with no insulation aside from a little paneling on half of one wall.
The basement stays NICE and cool in the summer, even with the A/C off. (The furnace (with the air conditioner unit attached) is in the basement, FWIW).

I am wondering about:

1). Having a powerful fan try and blow much of that air up the stairs by main force (since cold air will just sink if left alone). This will cost maybe 50 bucks for the fan, a bit of inconvenience of it being in the way, and about the electricity of running a light bulb. (I am also thinking this might work MUCH better if there is a ceiling fan in the room upstairs that the stairs enter into).

2). I am wondering if some more sophisticated circulation system (like say a whole-house fan and a laundry-chute hole type of arrangement -- to draw LOTS of cool air directly upstairs. This would be a fairly expensive arrangement, it seems to me.

(A friend has a whole-house fan to blow air from the house into the attic in the summer and he says it's really great. The fans might run $700 he says, so the big deal is constructing the hole and the fallout from that.)

[jeffgedgaud]

I know this is an older thread but I did want to add to the concept of using a basement for cooling a home, I Have been doing this for several years now and can definitely say it works till you sap out the cooling potential. I have lived in my 1904 home since 2009 and before that I live in a similarly constructed home before that and used the basement to help cool the home during the summer.

In both home the basements had brick or brick and concrete foundations in the basement and would stay cool for months into the summer. In my current home there is no convenient way to close a door into the basement so the steps to the basement are left open year round. My cats have their litter box down there so access is needed for that as well.

I started trying to use the coolness in my basement to keep the rest of my house cool when the summer turned hot about june here in Minnesota. I put a box fan in the doorway and now I use smaller fans hung at strategic locations to help blow cool air upwards as well as hot air downwards during the winter. My second floor is warmer in the winter than my first floor so I also reverse the air flow and try to blow some air downwards and it works pretty well.

I keep the basement sealed off year round and use that heat sink to ground to keep my house cool in the summer and avoid opening windows which can actually rob the house of the coolness coming form the basement. Last year I did a full insulation audit and had insulation installed all over my home in the walls and attic which helped tremendously but blowing the air around has also helped. I have a boiler and radiators so air is not moving well around the house but the thing that lets me know it works is how all of a sudden the basement will stop feeling cool after a few months of air being blown upwards.

Around September or so the basement will stop feeling cool probably because the soil around the house stops cooling the walls but the temperature will start to rise in the rest of the house by a few degreees. I can go all of july and august without using an AC unit unless it is really hot but the cool air form my basement being blown upwards makes at least some of my house feel nicer.

[Subjectivist]

When I had a house with a full basement I would set the furnace blower to low to keep the air circulating. When cleaning the element on the humidifier I discovered on summer that the unit would draw in the cool basement ai if I left the humidifier open. In the summer we have plenty of humidity around these parts so I left it open all summer and cut my A/C bill about 20%

In the winter there was one heat vent in the basement, which also had a half bath and the laundry room in it. I left it alone in winter and covered it in summer so that the cold air from the A/C was forced upstairs and seeped down the stairway because cold air is denser and falls naturally.

[PrestonSturges]

Also, it depends on how damp the basement is. Maybe you don't want to seal moisture down there and get weird condensation problems.

[Surf]

I did a large sealing project last year and plugged every hole I could find in the house and sealed all my exposed heating ducts. I did get a nice efficiency gain of about 20-25%, but my house still "feels" chilly when heated to 68F when occupied.

Have you had a blower test done to determine were air is leaking out? If the answer is no, there is a 90% probability that you missed some. And some of those might be big. It took me over a year to find the biggest leak in my place. A couple years before I moved in the owner had all the windows replaced. like most windows on the market each had weeping holes.

Weeping holes allow any interior condensation on the glass to collect in the frame and drain out. Also if any outside water penetrates the window seals that water will collect in the frame and drain out. However roof overhangs prevented rain water from ever hitting the windows and in my climate condensation is not an issue. So I didn't need weeping holes. And those holes were allowing a lot of air flow in and out of the house. I plugged them and now no ore chillls

As an alternative, what if I either insulated the basement cinder block walls. Or, what If I insulated the bottom of the first floor (aka the basement ceiling) between each first floor joist?

After you get the blower test done do all of that but before applying the insulation locate each wire, pipe, heating duct (I am assuming your furnace is in the basement). Pipes and wires in the basement must get to your first and second floors. Typically through holes drilled in the basement ceiling The gap between the edge of the hole and the pip or wire is a place were air can move through. Remove all basement light fixtures and plug any gaps. there will also be gaps around all heater ducts in the basement. use caulk or spray foam sealant Also caulk the point where the rim joist touches the cinder block. there is likely a small gap there that may be hard to see.

After that then insulate. However I would not use fiberglass. Fiberglass is cheep and the worst performing insulation on the market. Air flows through it and it's R value will drop as the temperature difference between inside and outside of the house increases. Spray foam insulation is stops air flow, has a stable R value and it will seal all gaps in the walls cause by pipes and wires.

Also keep in mind The fore every cubic foot of air that enters through your basement ceiling. One cubic foot must leave someplace. Have you sealed the gaps between all 2nd floor light fixtures and the Sheetrock? Go into your attic and look at the fiberglass insulation. Any dark spot on the normally yellow or pink fiberglass? Those dark spots are caused by air flowing through the fiberglass and leaving dust behind. that might point to any problem areas.