Could a single-family home ever be more eco-friendly than a small apartment?

I’d be curious about this too. From a water usage perspective, I am not sure whether small gardens or industrial agriculture are more efficient, and using city water to grow food is likely a more constrained resource than whatever sources farmers use to grow their food. From a GHG perspective, vegetables already have a fairly low GHG impact (around 2kg CO2e/kg of vegetables produced, according to this site), so even if you produced 50kg (~110 lbs) of vegetables in your backyard garden in a year and somehow did that with zero GHG emissions, that’s saving 0.1 tonnes of CO2 (only 0.6% of a typical American’s annual carbon footprint).

I’m not sure that “city water” is the right qualifier to use, there. Vegetables I were to grow right here (or more realistically, vegetables my mom grows, because when I attempted to garden, she still had more surplus than my entire output) are grown using Great Lakes water, a basically inexhaustible and unwasteable resource. Vegetables brought in from elsewhere are likely to be grown using fossil water, such as from the Oglala Aquifer. Now, maybe it’d be best of all to get vegetables from rural land outside of town, along the coast of the Great Lakes, but the “city water” veggies have to be better than the fossil water ones.

I don’t believe there is one set answer. I believe it depends on the circumstances. If a home has solar panels, and the apartment building doesn’t, it is more efficient. If a home has a recycling pickup service, and the apartment building doesn’t, it is more efficient. If an apartment dweller is an energy pig, but the home owner is energy conscious, the home is more efficient.

In terms of property, I as an individual apartment dweller do not have property, but my complex is surrounded by beautiful grounds. We have a courtyard with trimmed bushes, mowed grass, a gazebo, and trees. They require watering and upkeep. So, in a sense, I do have “property”.

That’s a fair point, the relative scarcity of water is going to depend a lot on what the source is. There is a nominal cost to “city water” in that it will have been treated to make it suitable for drinking, while I’m not sure what sort of treatment, if any, is done for agricultural water. I wouldn’t expect that cost to weigh in heavily on the sustainability of growing vegetables in the city, though.

Not entirely true, though. There is a limit to how many people each station can handle, and building new stations is extremely difficult.

These are the kinds of single-family homes we have in my area, in inner London:

(These ones might well have been divided into two flats per property).

I’m about a twenty minute walk from the financial district.

They do not take up the kind of space people might be imagining, but they are a common property type in one of the most densely-populated cities in the world.

FWIW, car ownership can be solved in other ways. Here pretty much every new development is car-free, in that the residents can’t get a parking permit (with some exceptions for several disabilities; and there’s no way you can park without a permit). And some of the new developments are houses, while a lot of them are low-rise blocks.

A lot depends on whether there is sufficient natural rainfall that you don’t have to water the garden or if supplemental water is needed, and if so, what is the source of that water.

At my old place a lot of the garden watering was done by nature. When more was needed it came from the well on the property, from an aquifer that isn’t being depleted so very eco-friendly from that viewpoint (would be even more so if the well pump was supplied by solar energy). Or you could use a roof cistern. Or greywater.

On the other hand, if you live in the Arizona desert an extensive vegetable garden might be less eco-friendly due to the need to supply more water than is naturally present in the environment.

Public transit being overused can be a problem, but the far more common problem is it being underused. A bus carrying 50 passengers is much more efficient than a car. A bus carrying one passenger is far less efficient. And building a new rail station might be difficult, but building a new bus stop might not need anything more than putting up a sign.

My house was assembled from factory-built modules and has a ground-linked heat pump for heating and cooling. There is no sewer service where I live, and local health ordinances do not allow simple septic tanks or sewage lagoons. Instead, I have a 3-compartment in-ground septic system with a settling tank, aerator, and filter. The filter gets cleaned every 6 months or so, and I have to get solids pumped out of it once every 5 or 6 years. It produces clear water which irrigates the yard downhill from my house using a leech field. (A buried network of irrigation pipes.) An alarm goes off in the house every few months to let me know when the aerator has something tangled in it, and I have to pull the aerator and clean a stringy grey ball of nastiness off of it.
I keep considering the addition of solar panels and fantasizing about getting an electric vehicle.

I was specifically talking about in cities, though. There really is not a problem with public transport being underused in cities.

Extra bus stops aren’t usually practical because they mean the buses are stopping even more often. None of the cities I’ve been to have too few bus stops. The solution is simple (not free, but simple) - you lay on more buses at peak times - but buses are so much slower than tubes and trains that many people don’t really have the option of choosing them.

For suburbs and rural areas the considerations would be different, agreed.

Apologies for going too much off-topic though. I think I’m coming from a very personal POV where, in London, every new large development is met with tears of frustration by commuters who are already having to queue to get into the station, let alone on the train. And cramming ever more people in leads to more light pollution, worse air quality, difficulties in rubbish collection, lack of green space for the wildlife that is still here… The high-rise buildings wouldn’t be able to function without the low-rise buildings around them.

I was talking specifically about cities, too. It may well be different between US cities and London, but around here, most cities have a hard time attracting enough public-transit riders to stay in their budgets.

Maybe so, but when were any roads and streets ever held up to a similar standard?

Sorry to be an arse, but could you provide a cite for that?

Most North American cities have trouble attracting any riders outside of rush hour in the suburbs. Inner city busses may be well used, but it’s not unusual to see a full0sized bus travelling the suburban routes with only 1 or 2 passengers. It’s a negative feedback spiral - people don’t use the bus because it only comes once every 30 or 40 minutes, and it only comes every 30 or 40 minutes because nobody uses it. As a result, everyone in suburbia needs a car, or two - one per adult. Then Junior reaches 16 and gets his own car.

An interesting thing I saw in Naples many years ago were buses about 1/3 the size of a regular city bus. Presumably these would far less fuel (nowadays, could be electric). Still, the biggest expense would be the driver - so maybe Elon Musk’s fantasy about self-driving taxis (or Ubers) would be a more efficient option.

The biggest advantage of owning a house in the suburbs would be that you can modify it to suit your desire to go green - regardless of the actual economics of the situation. Install argon triple-pane windows, upgrade HVAC to more efficient standards, install solar panels and battery (Musk Powerwall?), upgrade the insulation, even rip out the plumbing to install a grey-water system. (The downside of inner city houses is odds are they were built decades ago when such considerations were not even technically feasible). An apartment owner usually has to do the cost-benefit analysis - will argon triple-pane windows with UV coating save enough to reduce heating and AC costs? (If the tenant pays AC on their own meter, who cares?) Will that modification increase the value of the building enough should I choose to sell it someday?

Another point is that here in the Great White North there are times when green solutions simply cannot produce enough heat in winter, and relying on electricity (from natural gas generation plants) is far too expensive. i would guess that most new houses here use natural gas for heat. It’s clean, but it’s still carbon.

However, if you can also design your house to be efficient, so much the better - I’m not just talking about really good insulation, but also design and landscaping to minimize heating in summer and cooling in winter - i.e. shading, enclosed verandahs, awnings, etc.

i also dispute the contention of any tech that "but it also pollutes to manufacture and dispose of it. That presumably applies to any tech, green or not. The asphalt shingles on my roof need to be replaced every 20 - 30 years or so (unless the house builder was cheap and went with 12-year shingles.) That’s a substantial pile of material that was refined hydrocarbons and will be landfill. People moan about the manufacture of electric cars, but the consumption of resources to manufacture an non-electric vehicle, including catalytic converter, piles of electronics, and melting metal to cast a giant block of cast steel, the machining costs - the footprint is probably only exceeded by the non-fuel consumables, like engine oil and antifreeze, that will be consumed by such a vehicle in its lifetime.

In the end, the question will be - what’s your goal - reduce footprint at any cost, or reduce footprint at a cost not outlandishly greater than not doing so?

I like the solution they found when I was living in Bozeman, MT. The public transit there only had one bus running per route, and each route was an hour-long loop, so the bus would only come once an hour… but the schedule of those once-per-hour buses was set to correspond to the schedule of the university, the city’s primary industry. So in the morning, you could catch the bus and get to school 10 minutes before your first class, and in the afternoon, you could leave your last class and catch the bus 10 minutes later.

Anecdote:

I live in a condo (small apartment) which is not eco-friendly at all. Half the walls in my place are floor-to-ceiling glass windows. They are modern windows, double-glazed but still not as good as a properly insulated wall.

And again - they meet minimum standards, I’m sure, and probably exceed them. But the best windows are triple paned, argon filled, and have a heat-reflective coating. For an entire apartment building, putting in the best windows, especially floor-to-ceiling ones, was probably considered an “unnecessary expense”. Companies building apartment buildings are not in the habit of throwing a lot of money into something that does not produce enough of a return to justify the expense. With a house you own, however, you can spent whatever you can afford for motivations that may not include payback.

But… suburbs aren’t part of the city. So that’s confusing to me. Suburbs do have problems with public transport use, but suburbs aren’t cities.

I think the difference of opinion here between me and you guys might lie in difference between the UK and US understanding of “city.” I don’t mean the “technical” UK definition of a city, which is a place that has officially been granted city status, because that includes a couple of teeny tiny places, but what we actually think of as a city, which a lot of people quite reasonably confuse with “large town.”

While I’m definitely not saying that Bozeman, MT isn’t a city by US definitions, I wasn’t really thinking of places that have less than 50,000 inhabitants and 752 people per square kilometre.

Places with population densities that low will definitely have more difficulty sustaining public transport, agreed. They do in the UK too, but they’re not generally considered cities.

I’m not sure that’s a UK/US difference exactly - I suspect that at least on the US side it has a lot more to do with where you live and where you have been. I wouldn’t think of Bozeman as a city either (except in the technical, political sense) - but that’s at least in part because my neighborhood has a larger population than Bozeman and a density of 16,400 per square km ( as of 2010). The NJ town my daughter lives in is much less dense than my neighborhood ( although denser than Bozeman) and I definitely consider it suburban. It even has what I think of as one of the hallmarks of suburbia - it’s easier for her to get to Manhattan via public transportation than it is to get around her town.

But I might think differently if I had grown up where some of my cousins lived - their village had a density of about 650 people per square kilometer, but the surrounding town had a density of 72 people per square kilometer so in comparison, their village might have seemed urban.

Actually… in the US they certainly can be.

The “Chicago suburbs”, for example, comprise 16 counties extending into two adjacent states (Indiana and Wisconsin). Within those suburbs are five cities of over 100,000 people (Aurora, Naperville, Joliet, and Elgin in Illinois and Kenosha, Wisconsin) and eighteen cities over 50,000 people (In Illinois they are Waukegan, Cicero, Bolingbrook, Arlington Heights, Evanston, Schaumberg, Palatine, Skokie, Des Plaines, Orland Park, Tinley Park, Oak Lawn, Berwyn, Mt. Prospect, Wheaton, and Oak Park. In Indiana they are Hammond and Gary). So… 23 “real cities” by your definition are embedded within the Chicago suburbs.

Chicago mass transit does extend through the suburbs to a limited extent, but it’s also the third largest urban area in the US and on top of that there are constant battles over trying to maintain the funding and infrastructure for that mass transit. That into-suburbia mass transit is largely focused on people going into and out of Chicago proper for work and on the outer fringes (like where I live, between Gary and Chicago) you often have to use a car to get to the mass transit station.

As for density - Hammond, Indiana has a population density of 1285/square kilometer. As just one example.

I’m not sure comparing US and UK cities/suburbs are comparing apples to apples.

I think it depends on when the city grew its population. New York City, for example, is much more like European cities, with high densities and a shortage of wide lawn and picket fences - because it grew big before the automobile. It also has extensive and far-reaching suburbs (huge tracts of … land - not politically part of the city) but good public transport because the city destination is not amenable to automobile commutes.

More modern “cities” like Los Angeles and the newer metropoliti (?) like perhaps Phoenix or Minneapolis - did much of their growing after the automobile, and were designed for the automobile, and are latecomers (if at all) to things like public transportation. They suffer badly from the lack of transit riders, and devote more of their downtown to parking for commuters. Worse still businesses also tend to locate in the suburban sprawl, since the workers all have cars - thus aggravating the non-city aspect by failing to make the core a core, In some of the transitioning cities like perhaps Detroit, the flight to the suburbs both residents and business has led to a hollowing out of the central core of the city.

A perspective I see more easily from Canada is cranky American politics. In Canada, cities are creatures of the provinces, and the provincial governments often have no hesitancy to amalgamate urban areas for simplicity, efficiency and better planning. Beyond that, the provinces have no difficulty actually dictating some aspects of urban planning.

US states have a much more hands-off approach to municipalities, resulting in urban areas that are a collection of numerous tiny towns as well as to core city. Each of these is individually responsible for assorted municipal services. The state may actually step in to mandate, for example, regional public transportation authority, but generally seem to be much more hands-off than in Canada.