"Green" Construction

[ta]

In terms of "green" home construction, where do you get the most bang for your buck in terms of energy efficiency? Pointers to any online resources would also be appreciated.

Thanks.

[Steve Barker DLT]

cellulose insulation. generally cheaper than fiberglass and much much better.

[Publius]

ta wrote in news:17cc97f9-fe3f-4b4b-ad66-a6a340bc8172 @g1g2000pra.googlegroups.com:

Move to Baja. Then you can get by with a few poles and palm fronds.

[ta]

Thanks Steve, I'll check it out.

[Bill]

Those in Alaska know ALL about this subject. See links at bottom of the following link (below the world image)...

Main page...

[tg]

Sorry, styrofoam or equivalent is a better idea, in prefabricated panels or subassemblies, R-30 walls and R-50 roof. Try to catch This Old House somewhere---they are doing one of these buildings, although it is a ridiculously large monster.

My personal experience with peripheral-insulated slab construction makes me quite fond of it, although some people like basements. Does a nice job of air conditioning, and smoothes out rapid ups and downs of outside temp.

Also, some kind of heat pump.

-tg

[ransley]

, SIPS construction, passive solar design, Loewen R7 glass, A house is a system and insulation codes a minimum of whats needed. You need to do alot of research.

[ta]

..

Thanks, I'll try to check that out. Here in NC, we have a "healthy built home" certification that provides guidelines for defining their standards, and there is a whole section on insulation that calls for "rigid insulation", but the rest is greek to me.

"Rigid insulation installed as a thermal break at the slab edge (R5, 6" minimum, vertically installed)."

On the one hand, I should probably not micro-manage and just trust that the standards that are in place are good ones, but I'm just trying to define some "must haves" for homes that may not meet the HBH standards, and to address the variances within the standards.

For example, some certified homes have bamboo floors while others have concrete floors with radiant floor heat. All have heat pumps and dual- flush toilets and some solar-assisted heating.

Haven't seen any basements, but most houses in the South don't have basements.

[ta]

Thanks, I'll check out the links.

[ta]

Thanks, yes someone was telling me SIPs were a must.

[Eigendeeg66]

ggggggggg your a illusionist/?

[Cwatters]

Sorry if you know this but..

Styrofoam is polystyrene and there are similar foams that are practically twice as good (eg polyisocyanurate).

[tg]

Yes I know it that's why I said or "equivalent", meaning rigid foam--- but ok, it isn't exactly equivalent. :-) I'm not sure what is used in prefab panels---it used to be mostly styrofoam, but I would specify isocyanurate if I were having a custom building.

I figure ta will do some research.

-tg

[ta]

.

I am comparing two spec houses (not custom):

House1: solar-assisted hot water, isocyanurate insulation, "sustainable" oak flooring, low E windows, dual-flush toilets, hardi- board exterior and (surprisingly) a basement.

House2: solar-assisted hot water, blown cellulose insulation (which is touted as coming from recycled newspaper), stained concrete (radiant heated) and bamboo floors, dual-flush toilets, and hardi-board exterior. Basement is an optional upgrade.

House 2 is more expensive.

Yes, still doing research.

[tg]

...

I'm not sure what you mean by spec---are they built? If so, you can hardly have an optional basement ;-).

My inclination is to think about what would be an ideal---that is, go ahead and design a 'green dream house'---as a way to learn about the various factors and their relative merits and value to you. Builders are going to mix in 'features' just the way auto companies have options in packages, and it usually isn't worth the money.

I have researched blown-in cellulose as a retrofit, and the underlying problem is in the application---works fine as long as it is done very well, but you're not going to know up front. Since you are in a future tropical zone if AGW goes on, you should think about AC more than heating. That's why heat pump may be your best choice. Also what is R-value claimed and how do they justify it? Solar hot water is a great idea---wish I had it.

Stuff like bamboo floors doesn't sound like it matters that much really---is it supposed to be greener than oak or southern pine?

-tg

[ta]

om...

It's optional on the ones that haven't been built yet. It's a neighborhood project.

House1 is heat pump and House2 has mini-split a/c (this house is actually ductless).

From House2 specs:

"All exterior walls, and interior walls to unheated spaces, will be insulated with blown cellulose R19. The ceiling/roof assembly will have 12=94 cellulose insulation R38. All wood-constructed first floors will have R19. All internal partitions around bathrooms, powder room, and Master Bedroom shall have R11 high-density batt sound insulation. All windows and door jambs will be sealed. The exterior walls are 7/16=94 ZIP System Panel with STORMEXTM water-resistive barrier."

Don't have the specs on House1.

Yeah, I'm trying to find out about reliability and maintenance costs etc. These systems have natgas backup.

Generally, I believe bamboo is considered to be more "sustainable" since it can be replenished more easily and more quickly, and it's easier to harvest, and the oak in this case is FSC-certified.

I agree, it's not one of the more critical considerations, although I currently have bamboo flooring and, irrespective of any environmental benefit, I simply like the appearance better than oak.

[ta]

Ooops, they gave me some wrong information. Turns out it's open cell foam in the roof and fiberglass in the walls.

[tg]

I don't want to get into one of those philosophical definition things with you ta,;-) but I don't think R19, which is the legal requirement, can justifiably be called 'green'. Seriously, you should refine the question somewhat.

If the goal is to reduce energy consumption and associated consequences, then the thermal balance of the structure is the big deal. R30 walls and R50 roof will keep you cool in the summer and warm in (what you guys call) winter. Thermal mass, orientation of the structure, shading and working shutters, and so on, will also make a real difference. The *type* of insulation is irrelevant, as long as it functions properly over the (long) life of a well constructed building.

There is such a thing as a 'really' green house, but it's not likely to be found in one of those developments---although maybe the construction and environmental group people can give some counterexamples.

-tg

[ta]

Well, as I hinted at earlier, I wouldn't know an R19 or R50 from a B52 or an F18, so I'm just going by the "Healthy Home Built" standards that exist in NC. These are the standards that are used to define what is minimally "green".

Hey, we have "skiing" in NC and everything.

Well, the NC Healthy Built Home standard is probably just a minimum requirement for marketing purposes, but there is still some merit to the standards. At minimum, these standards ensure the homes are "greener" than your average home, if not ideally "greenest", by whatever standards those might be.

Obviously price is a major consideration too. If I was going to build a custom home that was maximally "green", then I presumably could afford to do all kinds of things.

I realize these "green" developments don't represent the ideal, and that there is probably some marketing fluff in there, but that's kinda what I'm trying to sort out . . . whether the "green" features are actually worth the premium.

You apparently believe that the features I listed are not enough to make it "really greann". So then what would you consider to be a "really green house"?

[tg]

OK, I see the problem. Are you saying that these HHB standards are

*not* a requirement? I thought they were part of the state building code. Your first step is to sort out what's what; I thought most codes already specified R-value, for example, as a result of the last energy crisis. So if someone is claiming that baseline as a marketing feature, I would stay far away from that builder.

-tg