California Architect Thinks About White Roofs

“But are architects thinking about these things?”

It’s hard to make wide, general statements about all architects, but yes, we are. The much better question is “are developers and owners willing to pay for these things?” And of course the over-general answer is no. The architect can only do so much prodding and urging when the owner/developer is essentially your employer and is covering all costs.

“Cool Roofs” as they called, are good for urban locations where the heat island effect is an issue, but often aren’t so useful in rural areas.

That mass of mechanical contraptions on the roof require very specific distances with no obstructions for ventilation. PV would be great, but couldn’t cover the ventilation and exhaust equipment and shouldn’t be flat on the roof anyway. They should be angled as necessary for the location. Also, I like PV as much as anyone else, but it’s important to remember it’s not the end-all-be-all of environmental design. It has a huge environmental impact itself, from the panels themselves, to the batteries and transformers, to transportation and manufacturing. The same is true of geo-exchange. There is still no “good” solution, only less-bad ones, and even those vary and depend on so many site and project related variables that it is very dangerous to sit back and back-seat design a project we know nothing about.

And finally, “Blah, blah, blah”…
A project that merely fulfills the program and engineering requirements is the ultimate in un-sustainable design. It will last only a few years before it’s owner or new owner grow tired of it and tears it down in favor of something new. Design, at it’s best, meets the program in a way that excites the user and gratifies the senses. A GOOD building will be around a long time because it continues to inspire the users.

Lots of glass & high ceilings = lots of heating & cooling – climate friendly? I would not think so. Zero energy? What are you smoking?

The 55 deg F ground temperature you talk about is a common misconception – CA typically ranges between 62 & 72 degrees – only some of the northeastern part of the state is below that. Ten feet under the ground? You would have to use a well and recirculating water or ground source heat pump.

The ‘horrible mess of mechanical contraptions’ on the roof are a screwup of the architect – all that could be hidden with some forethought.

That last paragraph from the architect is no more than fancy double talk meant to impress! It has no meaning in the real world.

These guys should take up a different profession where they might be better.

White paint ‘under’ the panels will help cools the panels making them more efficient. I understand what you are trying to say but it is quite wrong.

Instead of white roofs that just waste space, the law should require combined heat and power roofs, http://www.dawnsolar.com/downloads/DSSI_Combined_Heat_and_Power_System_Spec_Sheet.pdf , to reduce the fossil fuels needed to power and heat the building. The cost of a CHP roof beyond that of a standard roof should be assumed by the local utility and costs recovered from the building owner at the rate of the energy saved.

Russ, actually per UC Davis

“In California, for example, at a depth of approximately six feet, underground temperatures remain stable between 52° F (11°C) and 74°F (23°C).”

So, in summer, the water pumped through the pipes would come up at, at most 74 degrees, taking less energy to cool. And in winter 52 degrees is a good start on warming a house to 65 degrees.

@ cmaceachen; “It’s hard to make wide, general statements about all architects, but yes, we are.”

I’m glad to hear it. But, your dismissal of solar is so typical of architects. And wrong.

Solar doesn’t take more energy to make than other things that you will use anyway. Unlike all the glass, all the concrete, all the metal in this house – making solar generates many times its return on investment over the years.

Why don’t you get a solar estimate for your next project and see. You might be astounded at just the money that solar saves over 40 years.

The sort of people who commission houses of this size can save tremendous amounts of money with zero energy homes – ie someone with a $500 electricity bill will spend half a million dollars over 25 years for electricity at California electric inflation-rates (6.7%).

Half a million dollars spent on electricity if they don’t put in solar equates to a humungous carbon footprint using utility energy. Are you goiung to tell me that making solar panels (with a 25 year warranty) has an equivalent carbon cost????

(And actually, I should cost it out to 40 years, because that’s how long panels actually are supplying power in the real world)

If we are going to build houses, lets think about making solar part of the design.

(And I know the panels are ideally angled at 21 degrees true South, (I do solar estimates for a living) but this roof could have been designed to incorporate solar at 21 degrees, concealing the “mess” at the required distances and still look great!)

@ cmaceachen:

Sorry, meant to say $700 bill – for $500,000 spent over 25 years.

A $500 bill will wind up being $363,540 spent over 25 years.

The sort of people who commission these types of houses (don’t confuse the typical spec mcmansion bought by people who can barely afford the overpriced piece of crap with a house by richard meier which is a one-off work by a well-known architect) are hardly swayed by monthly energy bill savings. I know, you’re supposed to sell it to the clients with talk of lower energy bills and to the environmentalists with talk of the carbon-footprint, but the carbon footprint argument would be the better approach for someone looking to build a house like this. And yes, I’ve done solar calcs before; it rarely pays off. Though, admittedly, never in so-cal.

Regardless, your defensive response is typical of those who think environmentalism = PV panels. A truly sustainable project in this location would use completely passive systems. I’m not dismissing solar. It can often be a great asset to a project. But it also does not make a project “green”, and it has a long way to go before its efficiency is acceptable. I’m not just concerned with a project’s carbon footprint, but also it’s lifetime, the origin of the materials and their toxicity, the heavy metals and chemicals necessary for PV and wind power, water runoff, site protection, etc.

However, I hardly think this project, completed in 2001, and rather unique, is where the argument needs to take place. There are major wastes in the industry, in construction practices, in energy efficiency, and especially in building life expectancies. Developers have come to see their projects as short-term investments and wish to minimize up-front cost and quickly turn around and sell or lease their properties. This lack of real ownership and investment in a project is the major difference in American and European development, and the major reason why things like double skin facades, rain screens, efficient mechanical systems, and green roofs aren’t seen more often in this country. This lack of fore-sight, I think, is where the problem lies, and sticking arguably green PV on everything does little but lower your electric bill by 100 bucks a month. There are bigger fights to fight.

I still you are wrong about solar. The very fact that you cite one number “does little but lower your electric bill by 100 bucks a month.” suggests that you don’t realize that solar can power a mere 1000th of your electricity or all 100% of it.

It all depends on the size of the system in relation to your usage. Here in the the East Bay, I’ve encountered homeowners with bills as low as $20 (frugal type in 500 sq ft house in Kensington), and as high as $600 (running pool pumps and plazma tvs in Concord).

That Concord homeowner could lower his monthly bill by about $590 with solar to cover 100% of his usage (just pay transmission etc).

So its not some one amount for everyone: $100.

“So its not some one amount for everyone: $100.”

Of course it’s not. It was a generalized example, a rough average, and a generous one at that. I know full well that you can buy systems from $20,000 to $200,000 and beyond. And once again let me say, I am no opponent of PV. I’m merely getting tired of seeing environmentalism take the form of mere dogmatic devotion to sticking PV all over everything. In a general sense, complexity is the wrong direction. Simplicity of systems and refinement of design (in this case, that would mean siting, orientation, prevailing winds, consideration of solar gains and shading, cooling ponds, etc, etc, etc) are at the heart of environmentally sound design. I’ll grant you, Meier didn’t likely take a lot of that into consideration with this house, but I’m willing to bet some of that is in there. And more and more architects are.

We are not at all in disagreement on all the passive stuff, google-see susan kraemer buffalo house and susan kraemer design vernacular …but do I wish more architects were more open to solar. Especially on a house like that with the sea behind it.

I just sense some weird hostility to and ignorance about solar from architects.

While cool ‘white’ roofs are a good idea, people need to look before they leap when it comes to haphazardly mandating things before they know all the facts and consequences from their actions.

Studies have been conducted showing that highly reflective roof surfaces actually attribute to accelerated degradation of the building facades immediately adjacent and above these high albedo surfaces. UV is the main destructive component of any exterior material. When it’s reflected off of a white roof, it intensifies the UV exposure on material that was never rated to withstand such high levels of exposure.

So on the surface, yes; cool reflective roofs are a good idea, but like anything they should only be done if warranted and practical for not only the building it’s going on, but the surrounding buildings as well. I don’t think it speaks to much for sustainability if you’re essentially speeding up the destruction of the buildings surrounding you.

Hi Susan,

I like the house – don’t get me wrong on that point – however with all that glass & high ceilings – zero energy? Even with the best windows & lots of exterior insulation the house still will ‘eat’ energy.

Actually the water temperature at 50 foot depth a given location varies maybe 2 degrees F over the course of a year. The underground temperature in the north east of CA is typically 52 while the San Diego area is listed as 72 degrees. There are charts available about this on the net.

With hydronic cooling you typically end up using fan coils. For ‘in floor cooling’ you need to stay above stay above the condensation temperature which gives little cooling. If you don’t stay above the condensation temperature you will have a horrible mess with wet everywhere. The fan coils require a certain delta T across the unit to function which in turn requires the heat pump – either GSHP (geothermal source) or ASHP (air source). Even 50 degree water is marginal for fan coil cooling – with 60 degree water you can forget it.

As you might guess I have been through this recently in building my new home.

I have seen the data on the amount of energy expended in making solar panels vs. the energy return. In a decent solar location they are very positive. In Seattle, WA probably never.

Passive solar could be used very much more than it is around the world – same with solar air heat.

Have a great day!,
Russ

The level of discussion on this topic has been good. I guess I also have doubts about the solar payback figures. Does this include the degradation in output?
I have not seen a 40 year lifespan claim before.

I suppose many parts of California have optimal conditions and so the payback will be quite good.
I think it is hard to disuse these issues in general because requirements vary so much by location.

I don’t see how a white roof is going to cool the underside of solar panels. The purpose of the white is to reflect energy.

I used the DOE calculator to look at the cost savings from the most reflective surface I could find and for my location it did not pay for itself. (when the roof itself is very well insulated) But I would guess that there would be a cumulative effect in urban areas.

Clearly many architects are thinking about it. I am not an architect but I like passive design and have thought it was cool and underutilized most of my life. I would like to use it more but my clients do not want what I would consider to be good design. In general they only seem to want a house that is more impressive than their neighbors.

When they do talk about ‘green’ they are generally so confused by the hype that their expectations are unrealistic.

Hi Susan. I would like to ask your permission (or that of the copyright holder) to use one of the photographs in this post – the first one – in a post I’ve written on my blog on white roofs. I would be happy to link back to this post, giving credit for the photograph and to clarify that the photograph is being used for illustration purposes only.
(My post makes reference to the many photographs on the web of beautiful buildings with white roofs, and I would like to place this particular photograph directly below that particular paragraph.)