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Denver, Colorado was originally developed using the method described by Atkinson, since there was no method but solar for melting the copious snow the city received. As it grew, the traditional north-south grid was used... which to this day requires much more cost and effort to clear in the winter. Search Google: "maps denver central business district"



I thought I ought to mention that John Snow, not Richard Snow, was name of the physician who discovered the source of a cholera outbreak in London in 1854.

Kris De Decker


Thanks, corrected.



I grew up in Southern California, and I could never figure why the old centers had grids that tilted off the cardinal points (Los Angeles, Downey, Anaheim, the oldest part of Santa Ana, and many others).

Now I finally have an answer. Thanks!

Kris De Decker


Tim, if you want to know more about the Spanish influence on American cities, check out the book "Spanish city planning in North America", by Dora Crouch, Daniel Garr and Axel Mundigo (1982)




I love to read the detailed articles on low tech magzine. In this article one thing I could not get though is amount of saving possible. For ex: If a block with similar density is build with solar envelop how much energy in % will be saved compared to block without solar energy.

Chris Hall


Great article Kris - really enjoyed the perspective and detail.

Kris De Decker


@ Manoj (#6): It's impossible to give you a specific answer. In principle, you could save all the energy required to heat and cool buildings, and then the answer to your question would be 100 percent. In less sunny climates, this will be harder to achieve, and then the percentage would be smaller. Latitude is one thing, but of course the amount of sun also determines potential energy savings.

It also depends a lot on the comfort level desired by the occupants.

To give you a concrete example: I live at a latitude of 41 degrees north, so conditions here are less favourable than in Los Angeles (34 degrees north). However, I have the luck to inhabit an apartment that is oriented south-west, with unobstructed solar access. Although winters can be chilly (just above freezing point) and summers can be hot, my apartment has no heating or cooling system. It can get a bit uncomfortable here in winter when the sun does not shine for a couple of consecutive days (we reached interior temperatures as low as 8 degrees celsius or 46 degrees Fahrenheit last winter), but then there is always thermal underwear. The house is not insulated, but we have shutters to protect the windows after sunset.

My neighbour, who lives on the other side of the building, in an apartment facing north-east, spends more money on heating and cooling than on rent.



Interesting article ! And thanks for the sources, didn't know the density Atlas.

I've been "playing around" with this issue for quite some time also.

The work of Lionel March and Leslie Martin in the sixties (in Cambridge) should also probably be mentioned, two related articles linked below :

Also a kind of enumeration of possible building forms :
(threads linked are in English)



By the way if you had to recommend one of the three Ralph L. Knowles listed, which one would it be, the last one ?

Kris De Decker


@ Yves: it depends. His 2006 book is the most inspiring, and gives the best overview of his work (including many issues that were not covered in my article). His 1981 book is the best choice if you are interested in calculating solar envelopes yourself.



Thanks a lot for the info Kris, will try to get one of them

Val Zacharias


There is a wooden palace in Bangkok, formerly the residence of the King. It stays very cool without any air conditioning, in spite of 99 degrees F heat and 99% humidity. It is 20 years since I saw it, but it is probably still there as a tourist attraction.



A friend I shared this with brings up an issue: deserts support flat roofs happily enough, but houses in climates heavy in rain and snow (maybe mostly snow) tend to have sloped roofs (though big buildings often don't.) Most of the pictures of terraces are of layers of flat roofs; some thought to "we got four feet of snow" design might be given.



The Japanese version of passivehaus, called OM Solar, uses the rooftop as a heat collector, rather than the windows. This would seem an easier fit for cities as only the very top of the building needs guaranteed solar access.

There's a website describing it:

Very good for roof integrated solar too i should think, as it meets a panel's need for circulating air to cool it.

Joe A


I think many of the US Parks welcome center buildings are designed in this way. The ones that are usually have a sign that explains the reason for the sloped roof and the large windows that face the sun in the Winter.



Thought provoking article, though scant attention is paid to the situation of those of us in deserts. My cooling costs during the long, hot summers are considerably higher than my heating costs during the short, mild winters. I assume that orienting houses towards the northeast may help, but then again, it would be helpful to see that situation considered.



The article is interesting, but useless as it does not cover any of the actual numbers involved.

How much actual electricity can be derived from solar PV, or energy from solar thermal, vs. the amount of electricity and/or heat actually consumed by the residents of said buildings?

Having a more optimal design is irrelevant if the base capability supplied by solar in fact is orders of magnitude too small to supply the inhabitants.

Equally it is pointless if the less efficient use of real estate is not offset by energy savings.

The past articles posted by Low Tech Magazine were of far higher quality than this one - which appears to be an ad for mass architectural rebuilding.

Kris De Decker


@ Calvin: see comment #8. The answer to your question depends on many factors. I agree that this should be researched, but to date this research is not available. I could do it myself, but I can't do everything at the same time.

Of course some people will read this as an ad for mass architectural rebuilding -- as they would read anything like an ad for mass architectural rebuilding. The fact is that we are still building many new houses and cities on virgin land, without any regard for solar orientation. Let's first design these new neighbourhoods and cities for solar access, and then we can start talking about rebuilding what we already have.

By the way, many old buildings are relatively well adapted to the local climate, especially in sunny climates. It's most of the modern architecture that would be completely uninhabitable in a world with limited access to fossil fuels. We will have to rebuild these anyway. And rebuilding should not be a negative thing: some companies are specializing in taking buildings apart without destroying the components, which can then be re-used.



The energy consumption per capita in most countries is well documented.

Equally so, Professor Knowles and/or his students should be able to provide concrete numbers as to how much more efficient their proposed building styles/plans are vs. existing methods.

The delta between the per capita existing consumption and the efficiency improvement percentage times the average solar panel install would yield at least a first order approximation as to what the contribution of architectural style might be.

As for old buildings - frankly this is a completely unsupported statement. The reality is even a theoretically well planned subdivision can easily be disharmonized by a few players. One owner of a single story on one equally sized piece of land in a solar optimized development would still be perfectly within his/her rights to build upward - in the process denying neighbors the previously free access to solar energy.

Thus an architectural plan itself is insufficient. Access to solar energy must equally be regularized under property law. Equally the optimal harvest of solar energy could only be accomplished via central state planning - which in turn deprives the individual property owners of significant free will. Both of these areas are fraught with potential for abuse, as sub surface mineral rights, water rights, navigation rights, and numerous other cross property rights battles have demonstrated.

Peter B.


I'd like to note that the surface of a solar-enveloped building is bigger, and heat loss is proportional to surface. It would be interesting to know what are the ratios to existing buildings.

There could also be an aesthetics depate on whether this zig-zag street views are good or not. To me it seems like the sea holiday town Jesolo, where it felt like lost in an endless city, as the buildings gave no orientation where we are. Designers of such city grids / blocks / houses should take extra care on blending it with the rest of the city.

mark schuette


Great subject. although the concept of doing this on a mass planned scale is unrealistic considereing the low level of education and environmental concern in the general population and political scene.

the Passive solar science was quantified (documented via measurement and software developed to predict it) back in the late 70's by Los Alamos scientific labs (of atomic bomb fame)and the surrounding progressive builders in Santa Fe, NM.

but on an individual basis it makes soooo much sense. some reidential homes are built as net zero energy homes meaning they use no energy from exterior sources. AND they are conventional design with PV panels added- think of what we could do by paying attention to Passive Solar heating and cooling on top of that ! our buildings are our biggest energy users. its so simple and easy to do. its sick that we can't even do this. we are so hung up on some antiquated concept of aesthetics. Functionality is the new aesthetics! STILL most of the new buildings ignore these simple design principals. we will have to crash again and become poorer before we bet out of our cheap dirty energy box.




Both new built and existing densely populated neighbourhoods could benefit from underground annual energy storage, that means collecting heat in the summer and using it in the winter for heating.

Technology is quite simple and has a good economy of scale by servicing many houses or flat apartments with one borehole thermal storage system.

Other than thermal solar panels, a source of heat can be local electrical plants that are used for district heating in the winter. They do provide hot water in the summer too, but that's a small fraction of the heat released from fueled electricity production. Unwderground storage could allow recovery of full year wasted heat from city powerplants.

Here-s an example of such a system providing 97% solar heating requirement in Canada http://en.wikipedia.org/wiki/Drake_Landing_Solar_Community

Victor Escobar


The Heliodon link returns a 404.

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