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legitster

I'll be a resident contrarian and argue that building more houses in the SW is a good thing.

- The desert is probably the best place to build sprawling metropolises with the lowest ecological impact (overall)

- Cooling is more energy efficient than heating.

- Houses in places like AZ are implicitly less wasteful (no lawns, better insulated, etc).

- People like it

But the question is how to get water to these places? Especially knowing now that the Colorado River Compact was designed when rainfall was at historic highs. But I don't think there is any long term solution that doesn't involve California giving up on taking other state's water to grow high-intensity agriculture.

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>> Cooling is more energy efficient than heating.

How is that?

First thing ofcourse is everything we do as human, including our body is generating heat, for my cooling my home is FAR FAR FAR more expensive (thus i would assume more energy intensive) than heating my home.

>>Houses in places like AZ are implicitly less wasteful (no lawns, better insulated, etc).

This is largely government zoning or HOA's here, people outside of AZ could allow for less lawns as well. This would require a cultural shift. I would love to replace my lawn with something I did not have to mow, but my local government prevents that

>- People like it

Some people like, some people (like me) like cold climates, or places with seasonal changes. I would never in a million years live in the south west US, I prefer places that snow.

> but my local government prevents that

They mandate you have a grass lawn?

Yes, unfortunately, this is very common. I'm in South Texas (for a few more weeks before I move) and my municipal ordinance requires homes to have a grass lawn and for it to be maintained. No HOA here (main reason I bought this house). I pay a lawn service company monthly to manage it for me, because it's a huge pain otherwise due to the climate.

Are you sure? Most places I have lived, the wording of the local ordinance says "IF you have a grass lawn, it must be maintained". I don't think many places would have issue with a nice xeriscaped native garden or even a cinder lawn.

Depends on the place, for sure. Where I currently reside, the town is named after a particular species of tree, and it was required when all the homes were built that each property had one of this species of tree on the property. You are obligated to both maintain that tree (or replace it if it dies) and to have a lawn, this is actually the ordinance here.

I agree it's kind of ridiculous, but I also live in an area known for its onerous HOAs, and these ordinances are basically just a subset of that writ large, but without the worst of it. I'll still take this over living in an HOA.

Even in cities that do not call out grass, combination of ordinances make grass the easiest and most economical, one could not replace it with say concrete.

These are set in a variety of zoning, building, and maintenance ordinances

For your "native garden" depending on your meaning could be banned because the city classifies all "unmaintained plants" to be weeds in violation of the ordinance.

Various zoning and building codes outline ground coverings for run off, and flood control purposes.

Then you have separate regulations about shrubs and trees,

All of these combined make grass the easiest way to comply with the government even if the government does to implicitly require grass

Okay, but there's a difference in saying something is banned vs saying it is expensive/too much work.

I disgree, at some point you have a functional ban even if you have not come right out and banned a thing

If you put enough roadblocks, hurtles, etc in front of something it becomes a functional ban

Case in point see the 2 most controversial subjects of today Abortion and Gun Rights, with each political side attempting functional bans with out actually "banning" the thing out right

I think what the other poster meant is that “cooling in a warm client is less energy intensive than heating in a cool climate” which is generally true.

This is partially because the temperature deltas are smaller. If you are aiming for 70 inside and you have 95 outside, you are fighting a 25-degree delta. But if you want 70 inside and have 25 outside, that’s a 45-degree delta the system has to overcome.

Delta is one thing, but you're also fighting solar gain when trying to cool. Sure you can mitigate, but when heating, the sun is working in your favour. Winds are another variable.

That’s true, although solar heating in warm climates can be mitigated in some ways (roof color, attic structure/ventilation) and solar heating in cold climates is tough with a layer of snow on the roof. Bottom line is that there are many variables but a big delta tends to be energy intensive to overcome.

> cold climates is tough with a layer of snow on the roof

Snow is actually helpful by insulating. The sun is closer to the horizon over winter, so it's your vertical windows doing the heating anyway.

An obvious issue is how much sunlight you get over winter. Not just in hours, but in N. Europe, you might have continuous cloudcover and not see the sun for weeks at a time.

Snow is not helpful for solar heating, as I said, and if your roof has a big r-value to begin with the snow is not adding a ton of insulation.

oh yeah, and snow reflects light off the ground. It's much brighter outside after coverage by snowfall.

If you are in a weird climate that gives you cold temperatures but consistent sunlight maybe?

But you are also dealing with angle of declination. Solar gain will be diminishing the further north you go even if you get sunlight.

High elevation can do that, but cloudcover is a lot heavier than much of Europe over winter than in much of North America.

Yep, and it’s why building codes are usually more rigorous in northern states. The approach to homebuilding in the south is to assemble our flimsy, leaky boxes as quickly as possible and slap an oversized AC on it.

Passive houses are much easier to build in cold climates than warm. Your analysis left out that the occupants and their machines generate heat.

"Together with the comprehensive energy conservation measures taken, this means that a conventional central heating system is not necessary, although they are sometimes installed due to client skepticism." - https://en.wikipedia.org/wiki/Passive_house#Space_heating . See also https://en.wikipedia.org/wiki/Zero_heating_building .

Neither of your links say that passive houses are easier in cold climates.

Under the section "Tropical climate needs" at https://en.wikipedia.org/wiki/Passive_house#Tropical_climate...

> Passive cooling, solar air conditioning, and other solutions in passive solar building design need to be studied to adapt the Passive house concept for use in more regions of the world.

> There is a certified Passive House in the hot and humid climate of Lafayette, Louisiana, USA, which uses energy recovery ventilation and an efficient one ton air-conditioner to provide cooling and dehumidification.

Earlier, "In August 2010, there were approximately 25,000 such certified structures of all types in Europe. The vast majority of passive structures have been built in German-speaking countries and Scandinavia."

I saw that, nothing there says that cold climates are easier.

I see "easier" as meaning different things.

1) it's easier in the Scandinavian and German-speaking countries because passive house building materials are easier and cheaper to acquire ("other countries may spend 8% more on constructing Passive Houses than conventional buildings because the Passive House components may not be readily available" - "Examing the Prospective of Implementing Passive House Standards in Providing Sustainable Schools", https://aip.scitation.org/doi/pdf/10.1063/1.5031991?casa_tok...)

2) it's easier in cooler areas because there's more experience in how to build for those climates (as Wikipedia points out).

3) it's easier in cooler areas because the energy saved is higher, and so easier to justify economically. "Passive Houses for different climate zones" at https://www.sciencedirect.com/science/article/pii/S037877881... shows "Energy demands of the Reference Passive Houses in the different locations" in Table 3, with:

            Yekaterinburg  Tokyo   Shanghai   Las Vegas   Singapore  Abu Dhabi
   Total saving  96%        90%       87%       86%         79%        77%

Those are all good savings in power use, but clearly better in colder climates.

(Sorry, I can't find TCO.)

4) From my understanding, it's easier to well-insulate and let body heat and appliances provide the heat, using the cool exterior to regulate temperature, than it is to deal with cooling and humidity issues in warmer climates to bring the internal temperature to the "inner comfort range" specified by the Passivhaus Institute, Fig. 8 of the link in 3).

As the other commenter posted you have solar effects, and as I stated you have other things that are putting off excess heat.

For me even when it is 25 outside occupied my home will settle at about 40-50 or so with no heat, due to just cooking, lighting, compters, TV etc that are all outputing heat...

so the delta I am attempting to heat is not really 25 to 70, but more like 50 to 70 due to the waste heat and solar heating effect

For cooling I am not not only battling the outside delta, but also all of that waste heat and solar heating effects

Houses in AZ use less energy on average than other states: https://www.eia.gov/consumption/residential/reports/2009/sta...

And in aggregate, cities in warm climates are more sustainable than in cold: https://iopscience.iop.org/article/10.1088/1748-9326/8/1/014...

>> This would require a cultural shift.

Agreed. Or people can move to places like AZ or NV where lawns are the exception.

>> I would never in a million years live in the south west US

Agreed. I like the PNW too much to move. But my argument here is just letting people do what they want (move to warm deserts) is a net benefit to society.

>Houses in AZ use less energy on average than other states

hmm, looks like energy expenditures are the same, they note that energy costs are higher in AZ

So the question would be is the reduction due to budgets, meaning given the option the people in AZ would set their AC lower, and be more comfortable if they could afford too and the high cost prevents that

Or is it actually more efficient as the claim was?

> The desert is probably the best place to build sprawling metropolises with the lowest ecological impact (overall)

Ecological impact includes draining aquifers and diverting rivers.

Human civilizations, particularly dense ones, have preferred oceans and rivers near temperate rainforests (like the entire Northeast) for this reason. The marginal advantages of less heating aren't outweighed by the resource and economic advantages of living near large bodies of water in areas where the geology and ecology actually supports it.

That doesn't mean it has to be the case.

Israel is a good model for how you can invest heavily in desalination and irrigation efficiency and support profitable agriculture, even in wasteland spaces.

Sure. It's all a manner of economic and political pressures and weights. We can also colonize the Moon or fill in the New York Harbor, but there are much cheaper and more realistic alternatives.

Israel is an unusual case: it's a state that exists more or less by religious mandate, meaning that its residents have gone above and beyond ordinary economic and political forces to make it livable. Lots of individual outcomes there can be applied elsewhere (like drip irrigation), but much is also politically infeasible in the US (like Israel's central authority that progressively taxes commercial water use.) Ecological variables also differ: the majority of people in Israel live in the Northern half of the country, which is wetter and greener than the American Southwest. That's also where agriculture is concentrated.

Point 3 - the article explicitly mentioned lawn sprinklers, a pool for bathing horses, and some other things that most definitely DO waste water. And are they required to be better insulated?

Sure, but on average less than northern cities.

At the end of the day, I don't actually care about moralizing what's wasteful or not if the owner is being charged the proper cost to acquire. If that's $1 a gallon for solar and desalination/recycled water, enjoy that lawn.

(Pedantic person side note: pools are not actually that wasteful. If they are properly covered when not in use, evaporative loss is actually pretty minimal).

> Sure, but on average less than northern cities.

This isn't true. Compare NYC's average of 117 GPD[1] to TMWA's 165 GPD[2]. That's 40% more water use, per individual. The last year that NYC's residents came close to using that much water was 1996.

[1]: https://www1.nyc.gov/site/dep/water/history-of-drought-water...

[2]: https://www.nevadatomorrow.org/indicators/index/view?indicat...

Swamp/evaporative coolers might be a big part of that difference.

Water in the Southwest has never been charged "the proper cost to acquire."

It's being pumped out faster than it can be replenished. Rivers are drained dry.

People have built for decades on the belief that water will never be its true cost.

Now it's the end of that day.

The "proper cost to acquire" isn't enough. Who pays the cost of repairing the damage done, like groundwater-related subsidence? Of restoring ecosystems?

I don't actually care about moralizing what's wasteful or not if the owner is being charged the proper cost to acquire.

In theory, I feel the same way. However, I'm not sure anybody is paying anywhere near the proper cost with externalities included.

> People like it

This one doesn't hold water (no pun intended). Over the next few generations, people in the US are going to have to give up a whole lot of things they like.

> - The desert is probably the best place to build sprawling metropolises with the lowest ecological impact (overall)

The only problem is then these metropolises are in the desert, and you have to ship all agricultural products to them. That's fine most of the time when times are good and supply chains work, but it's fragile, if anything goes wrong enough in the worldwide food markets. A desert metropolis is like an island nation that must import all its food.

A precarious position if times ever get tough. I believe currently the USA is a net exporter of food products, but if you started building and growing enough desert cities that might stop being the case

You are going to need to provide a source for your claim that cooling is less efficient than heating. AFAIK from my days as a mechanical engineer, heating from an electric source is ~95% efficient and cooling is ~30% efficient...

Heat pumps have COP of 2-4, so in either heating or cooling mode, they generate more heating/cooling than electricity used.

But the reason cooling is cheaper is the temperature differential. AZ might get to, say, 110°F peak (and far cooler at night), for a temp delta of 35°F while the Midwest will stay below 20°F for months, and even colder at night, for a temp differential no better than 50°F during the day and 60°F at night.

And heat pump efficiency takes a dump when it has to go through defrost cycles in heating mode at near/below freezing temps.

In cooling mode they provide a source of fresh-distilled water! It always bothered me when air conditioners just dump that water down the sanitary drain instead of pumping it in a garden or misting it on the outside coils.

Yeah, air source has problems at cold temperatures, especially if they cheap out on ice detection.

Fresh is not the word I would use for condensate. Try drinking some of you disagree :). It's corrosive for metal,{EDIT: maybe I just have that confused, see replies} which is why it usually doesn't find a purpose, but you could run it to plants. I have a window A/C which uses it for cooling the outside coils though.

Still wouldn't drink it unless I'm desperate, but I don't see why it would be corrosive. Maybe slightly basic from being in contact with metals, but it couldn't be much unless your coils and fins are disappearing before your eyes.

Legionella is a concern though.

https://www.environmentalleader.com/2013/01/air-conditioning...

I think it's the lack of minerals? But it obviously forms on metal coils to begin with. Maybe I'm confusing it with condensate from condensing natural gas burners.

> "...they generate more heating/cooling than electricity used."

that's thermodynamically impossible. @dktoao, being a mechanical engineer, surely understands this, and made a statement that is different, and more plausible.

COP is a ratio of change in energy (e.g., temperature) produced against a common benchmark (running electricity through a resistive element, for example). that's how it can be greater than 100%. absolute efficiency (what @dktoao offered) compares against a 100% conversion of energy from one form (or place) to another. in this case, you cannot beat 100% (or generally get super close) due to the 2nd law of thermo.

Basically no common A/C is 30% efficient in any sense of the word. There's a scenario where you can argue it can get as low as 50%, but no common A/C I have ever heard of is using moving less than 2x heat power as electricity power used. 30% is wrong no matter how you cut it.

And, "efficiency" doesn't matter. COP does. COP is what is reflected on your electrical bills.

it's basic thermodynamics. you mixed the two, as i explained previously, and now you're leaning into the misconception, rather than acknowledging the difference.

In no way is anything you said in either post of use to anyone.

If I am in my house, use 1000 W of electricity, get 3000 W of heating, that is what is important. No shit the extra heat comes from the environment. It doesn't matter unless you live within a house completely located inside an artificial climate-controlled area, which applies to... none. No houses.

It is two different modalities of heating though. Electrical heating is 95% efficient at dumping energy from the grid into your house, but a heat pump is using energy from the grid to concentrate and move heat from outside the house to the inside (which is itself unintuitive to people when it is already much colder outside the house than inside). So how do you develop a fair comparison of the two in total energy expended to keep the building at the desired temperature?

Probably heatpumps, depending on the climate. Heatpump effectiveness drops off rapidly as you head below 0C.

Considering the temperature extremes that southern US versus northern US housing experiences over the entire year, it's probably easier to keep the southern house around 21C than the northern one.

Swamp coolers can be several hundred percent efficient.

https://iopscience.iop.org/article/10.1088/1748-9326/8/1/014...

https://zeroenergyproject.org/warmer-climate-construction-de...

https://www.eia.gov/consumption/residential/reports/2009/sta...

Sure, but in a cool climate you need much less cooling to be comfortable than you need heating in even a neutral climate.

These desert ecosystems are much more sensitive though.

If you disturb prairie it comes back after a couple of years of rain. Not so the desert.

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