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No heat on today!

Posted by Reyesuela (My Page) on
Wed, Feb 18, 04 at 2:48

Oooooh, today was nice! No heat on in the house--today
OR tonight! It's in the 30s, but the house is still toasty from the passive solar earlier today.

Whatever you do, build with passive solar! It's virtually free, and it saves lots of money, makes your house filled with light, and just plain FEELS good.


Follow-Up Postings:

RE: No heat on today!

Are there any good websites that explain in very simple laymans terms what it takes to build passive solar. Maybe a list of things we could do -- the only thing I have heard of building passive solar is windows on the south side of the house, but I need a lot more details even on this one thing. What percentage of the south wall should be windows ? What about the other walls ? What kinds of windows ? How much of an overhang for the eaves ? Does it matter if the house is one or two story ? What if the house isn't *exactly* oriented south ? etc, etc.

RE: No heat on today!

The following links may help you find out more about passive solar.

RE: No heat on today!

The most important advice is to minimize windows on the north and west sides and maximize windows on the south. (In fact, put a garage on the north side if you can!) And get the eaves right.

Have at least 20% of the south-facing walls be windows, and get the depth of the eaves correct so you don't get sun in in summer and get plenty in winter.

Adding thermal mass is REALLY optional, and it's the part of passive solar that adds cost. Every wall, every floor covering has thermal mass even if it isn't specifically chosen for that reason. (I don't have any added thermal mass to my house!) If you want to go that route to even out temperatives, using water is no longer recommended. In fact, I'd just put up an internal brick wall.

For passive solar, insulation is really important, too, but it's important on any well-build house. *g*

If you overdo it, you can just open windows in the winter. If you underdo it, you're stuck!

RE: No heat on today!

Thanks. I will go look at those sites and see what I can learn. We would really like to build a house as energy efficient as possible.

RE: No heat on today!


If you under-do it - invite a friend over on cold days who's full of hot air.

Enjoy your mountain eyrie, eagle.


RE: No heat on today!

*g* Doesn't take much here to make it HOT! That's one advantage to New Mexico. Most sunlight anywhere in the US!

RE: No heat on today!

Another good design feature for passive solar is to build closets on the north side to take advantage of minimal window space. The closet space provides another level of free insulation.

RE: No heat on today!

Solar energy being utilized for heat has been around nearly as long as man - a south-facing cave entrance is much more desirable, as are south (better yet is southwest) facing step, driveways, and the biggie : windows.

Solar energy may well work out twice as well in New Mexico as opposed to south-east PA - but it still works.

IMO, the south-west wall should be at least 50% windows.

I do not favor closets along any wall, they should be about in the middle of a floor-plan and must be ventilated, even heated.

RE: No heat on today!

Yeah, if you have cloests on the N. side, you end up with a heat vaccuum. You HAVE to open closets,a nd pretty often, so that's not good.

A garage on the N. side works out much more nicely.

RE: No heat on today!

A "heat vacuum", Rey, what is that ??

A standard closet along an exterior wall, unless that wall was insulated to R-100 or so ( 3 feet of sealed styrofoam) would be a "poorly conditioned area", but would reduce the heat load by 5 to 10%(depending on their size).

But, I do not like the "poorly conditioned" thing, the closets must be at 50 degrees and be well vented.

The north-side is the good location for the garage. But the driveway must receive sunlight.

And I know that R-100 is not economically possible and that 3 feet of Styrofoam is too costly.But, I have considered this in an effort to have a home which can be heated with a candle..

RE: No heat on today!

Closets must be opened--usially several times a day. If you stick it on the north side of the house, it will be very cold in the winter when you open the door. Because of this, it would not reduce the heatload one bit without a ridiculous amount of insulation--in which case, why bother with the closet????

I was using the term "vacuum" colloquially. If you want be to be precise (though I think it's silly), here you go:

According to the laws of thermodynamics, energy must always move "downhill"--that is, from an area of higher energy to one of lower energy. At the same time, the net level of entropy must increase. Because of these two parts of the law working together, any warm space next to a cold space try to reach an equilibrium with the cold space by dumping heat into it until the temperatures (the average kenetic energy of the molecules) are equal. That would mean, simply, that the closets would try to be much colder that the rooms--and the rooms would then try to reach equilibrium with the closets, but with the constant input of heat from the heating system, they'd stay much warmer despite that. Until you opened the closet door. Then, diffusion through Brownian motion and the air current you just made(which are both much faster than conduction through a door) would cause a wash of cold air, making the room suddenly unpleasantly chilly.

Happy now?

RE: No heat on today!


Equilibrium is an important thing to consider in a passive solar house.
I left as much open space as possible between rooms and floors in a 3 story house I had in Vermont.

It had about 75% glass on the south wall and concrete floors and walls on the first floor. There were almost no walls between rooms and the staircase was completely open from top to bottom: open treads and steel cable between the posts that held the handrails. We even used glass French doors in the bedrooms to reduce the insulating effect.

The HVAC guys thought I was nuts when I asked them to reduce the amount of baseboard on the second and third floors. (The lowest floor had radiant in the concrete slab.)

The temperature difference between the lowest floor and highest ceiling was 2F in winter. The baseboard heat almost never came on in the upper floors.

The radiant heat had a lot to do with it, but the sun warmed up the slab even on cloudy days and the boiler rarely kicked in until relatively late in the evening.

As I suspected, keeping it cool was more of an issue than staying warm; but opening a window and/or skylight took care of that and provide fresh air too.

The only downside was acoustic. With all that glass and concrete, plus bare hardwood floors, sound carried a little too easily between floors. We could have solved that with more carpet and some curtains, but never got around to it before we sold it.

RE: No heat on today!

I know. That's why I said that closets on the north side would be a bad idea.

RE: No heat on today!

About 40 years ago I built a summer cottage on a hillside facing south toward the sea on the west coast of south Korea.

Front wall concrete blocks about 15' high with vents near the top of the wall. Corrugated metal roof, bright to bounce much of the light and sloping down to about 7' at the back wall, about 20' behind front wall. That left sunlight hitting the whole roof at a long angle, so producing much lower heating factor.

Poured concrete floor. Living area just inside the front wall, with substantial length but not height of windows.

Two? bedrooms at back, with light walls about 7' high, leaving about a foot of open space at the bottom for good circulation of air. There was usually a nice breeze.

Though the area was below 38 degrees latitude, we never found the building uncomfortably hot.

Good wishes as you seek to tread lightly on this precious earth.

joyful guy/Ed

RE: No heat on today!

Over 20 years ago my wife and I built our earth sheltered, passive solar home. We have two homemade solar water heating systems also. Feel free to ask any questions, Doug

Cedar cordwood article-

This is something I wrote about 6 years ago when Greenpeace asked me to
give a talk, I wrote this up, and never got a chance to talk, so I sent
it to Countryside. It`s a little long, and I took much of it from other
sources.- and go to the first,
featured article. The house looks totally different on the outside now.

Another article house related, use the index on the left
to go to the article-
Building Walls with Stone

Here is a link that might be useful: Doug`s solar

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