[cross-​​posted to Urban Sprawlette]

We’ve made a lot of progress on the Nudge project recently, and it’s time to think seri­ously about poten­tial appli­ca­tions. Infra­struc­ture is in place for auto­matic dis­cov­ery of struc­tures, algo­rithms, pat­terns, mod­els, equa­tions… but when you’re build­ing a tool it’s all just play-​​talk until you con­sider some inter­est­ing chal­lenges and see if you can frame them read­ily as some­thing your tool seems use­ful for.

At break­fast yes­ter­day Bar­bara and I spent some time riff­ing on var­i­ous “hard” design and opti­miza­tion prob­lems that it would be nice to solve. And since we’re think­ing of our ubiq­ui­tous and time-​​stealing house, her thoughts went towards HVAC.

In par­tic­u­lar, the eso­teric (but eco­nom­i­cally impor­tant) cal­cu­la­tion of how to size air cool­ing equip­ment for a build­ing. The stan­dard — that is, the Stan­dard — is spelled out in Man­ual J, now in its eighth edi­tion from the ACCA.

Here’s how it works, in prin­ci­ple: You want to build a house? You’ve got it designed, with floor­plans and sit­ing and what most folks think of as “design” done? Well, how large does your A/​C sys­tem need to be?

A good sales­man or con­trac­tor, espe­cially one who doesn’t really care how much money you spend after you leave his care, he can pick some­thing he’s famil­iar with that’s “big enough” to man­age tem­per­a­ture con­trol and ven­ti­la­tion and such, regard­less of whether your house is super-​​insulated or what fancy-​​dancy win­dows you’ve got. Heck, that’s easy: the biggest you can afford.

If you press a pro­fes­sional con­trac­tor that this kind of approx­i­ma­tion isn’t exactly what you had in mind when you set out to save energy costs and cre­ate a “smar­tish” house and save in both short and long-​​term, he can turn to Man­ual J to do a “proper” calculation.

Man­ual J is big. I haven’t seen the copy I’ve ordered from the library yet—and even that’s the abridged version—but I know that there’s a com­plex algo­rith­mic cal­cu­la­tion. The required cool­ing load cal­cu­la­tion of a house depends on the size and posi­tion and mate­r­ial of win­dows, the over­all enve­lope, the insu­la­tion, posi­tion, geo­graph­i­cal loca­tion, foliage cover, exposed foun­da­tion, ceil­ing heights… loads of stuff you might con­sider “design vari­ables” if you weren’t already hold­ing a fin­ished house plan in your hands. As far as I under­stand it, the con­trac­tor enters this infor­ma­tion into an ACCA-​​designed spread­sheet, Excel stuff hap­pens, and out pops a slightly less sales­man­like esti­mate of the HVAC needs of your house. And then you can refer to Man­ual S to pick out equipment.

Now look­ing at the ACCA descrip­tion of the work, I’m see­ing things like this:

MJ8 also accom­mo­dates homes that have excep­tional archi­tec­tural fea­tures and life style acces­sories such as:

• Dwellings that have lim­ited expo­sure or no expo­sure diversity
• Homes with large south-​​facing glass area or rooms with unusu­ally large glass area
• A ther­mally iso­lated solarium
• Cus­tomized inter­nal load estimates
• …

And so on, for 561 pages, nominally.

Now you might be able to see where I’m head­ing by now, and you’d prob­a­bly be right: That’s sounds like a nice place to slap a pat­tern dis­cov­ery system.

And so I think we will.

But what I’m sit­ting here think­ing about is the ACCA itself, and the social process that goes into eight con­sec­u­tive edi­tions of this sprawl­ing empir­i­cal model. There must be reams of data… some­where, and there must be reports and whitepa­pers and sup­port­ing evi­dence that makes clear the design process under­ly­ing the Man­ual J model (let alone every­thing up the Man­ual S (which is the highest-​​lettered I’ve seen so far).

As an indi­rect cus­tomer of the ACCA, I have to say it would be nice to have access to that data. To try to deter­mine whether a sim­pler, clearer model might be more accu­rate and robust than this spread­sheet. A his­tory of the mod­els, a pub­lic record of how things are done. Oh, hell, maybe a con­ver­sa­tion about what might actu­ally be going on.

But I’m a dreamer, surely. Some­body has to pay for all that data col­lec­tion. Not every­body is trained well enough to man­age the com­plex cal­cu­la­tions under­ly­ing the first-​​principles mod­els or the empir­i­cal analy­ses. What would hap­pen to stan­dards of qual­ity if any­body could chime in and crit­i­cize or amend some­thing as impor­tant as these cal­cu­la­tions?

After all, the goal of the ACCA is to make “the indus­try more successful.”

Nonethe­less, I’d like to be con­sid­ered a part of that indus­try, speak­ing as a tech­ni­cally astute con­sumer who pays their bills. I’m more suc­cess­ful when­ever exper­tise is not masked by obfus­ca­tory grav­i­tas, when deci­sions can be clearly jus­ti­fied, when data can be re-​​used and expanded at will. When peo­ple can see what’s going on inside, and participate.

So I’m increas­ingly tempted to reach into the build­ing trades, specif­i­cally through their mul­ti­tudi­nous stan­dards orga­ni­za­tions, and start chip­ping away at some silo walls.