> New York City's population density is 56% higher than San Francisco's

And even New York City is not really that dense:

    San Francisco: 18 000 people per mi2
    New York City: 27 000
    Barcelona:     41 000
    Paris:         55 000

Only Manhattan (72 000 per mi2) is dense.

New York City is vast. Brooklyn alone is 40% larger than San Francisco.

If you're talking about outlying areas, the rest of the bay area is amazingly not dense given how expensive housing is.

You can't really compare a single municipality to several that collectively equal it's size. The latter case has a whole lot of more localized and conflicting political interests that serve to hold back the area as a whole.

Note New York City has less of these issues because over the centuries it gained control of its neighboring areas from other counties, something San Francisco never did.

But given how fervently anti-development San Francisco itself also is, would it even have helped?

San Francisco looks positively pro-development compared to places like Palo Alto. At least they allow townhomes, not requiring detached houses with large lots. If more of the Peninsula were even near SF levels of density, the housing issues would be a lot less severe.

I know they're different politically - I'm comparing the results, which are terrible.

Or look at Hong Kong and Singapore.

That's twice you've said that, care to elaborate?

Hong Kong 6,544/km2 17,024/sq mi

Singapore: 7,697/km2 19,910/sq mi

Hong Kong is 75% rural montane forests. The city density is closer to 80000/mi^2.

An unsurprising choice, since for a century residents were surrounded by a much poorer, much more dangerous country, and the ocean, in all directions. The only place you can go in Hong Kong to escape are its parks.

Those numbers are the population densities for the whole countries. I wasn't able to find densities for the urban areas of Hong Kong or Singapore.

Btw, Monaco is at 48 462 people per mi2.

Singapore is reasonably dense as a whole for around 5 million people.

If you look at the high numbers for Barcelona, Hamburg or Paris, that's only the urban core. Singapore, of course, also has a denser core.

(And what scythe said about Hong Kong.)

Do you happen to know how many units the largest residential building in NYC has? It would be interesting to know the minimum number of buildings needed to cover the 200k unit deficit.

[edit]

Thanks for all the replies!

So it looks like we are talking about a minimum of hundreds of buildings to be torn-down and rebuilt taller. That seems unlikely to happen in SF proper.

"A West 57th Street project by developer TF Cornerstone will be New York City’s largest apartment building when completed, with 1,189 units, according to city records."

http://therealdeal.com/2013/11/12/tf-cornerstones-606-west-5...

3333 Broadway has 1200. It's technically five buildings, although they are all connected, so I don't know how they decide that.

https://en.wikipedia.org/wiki/Riverside_Park_Community

It's also a monster of a building. I kind of get the NIMBY vibe if it's about that, it's just too big, sucks up all the energy.

There are a few like that this (Galaxy Towers in Guttenberg). They're all old, though, they don't build new stuff like that.

I don't know about New York. I lived in a two-tower complex in Chicago, 45-stories with over 1,000 apartments total.

But you don't need tons of high-rises. Having everything be free-standing buildings is the larger problem. Blocks of mid-rises is what drives density in places like Paris: https://agingmodernism.wordpress.com/category/sarcelles.

423 Park Avenue is the tallest [1]. 412 637 square feet, containing 104 apartments.

I have no idea what fraction of the floor area is apartments, but if it was all of it, they would average 3968 square feet, which seems huge. If everyone got the same modest but comfortable 820 square feet i have, there could be 503 apartments. At that rate, you'd need about 400 towers to make 200 000 apartments.

[1] https://en.wikipedia.org/wiki/432_Park_Avenue

A pretty high fraction of each floor is apartments, the problem is that the apartments are huge. I'm pretty sure the penthouses actually span two floors. The lower floors probably have 2 or 3 units per floor.

More moderate apartment buildings would have had several units per floor, but that building was built to be the most prestigious in the city.

Interesting idea. It looks like the largest in terms of number of units built in 2014-2015 in NYC was 815 units, so you would need 246 of them to get to 200000+ units.

http://therealdeal.com/wp-content/uploads/2015/07/NYC-Condo-...

That 815 units was a proposal, not something that's actually been built. It appears the company intending to build it has since cut the proposed size to 646 units, and that's big even for NYC - the biggest on that list that's actually being constructed is 246 units and the sizes drop rapidly from there. So you'd be looking at a thousand or so NYC-sized buildings, in an area probably considerably less suited to them than NYC. (Oh, and the estimates I can find claim that apartments in that building are selling for about $2,000 per square foot. I think that's expensive even compared to SF prices. What's more, anyone who complains that SF housing development is too slow needs to realise that 246-unit building is part of a construction project originally proposed in the late 80s: https://en.wikipedia.org/wiki/Riverside_South )

Not one building, but the Stuyvesant Town complex in Manhattan has 30,000+ residents and it sits on 80 acres with 89 buildings, and lots of green space, basketball courts, etc. It's a very livable place.

I dunno, but the Rincon towers in SF have something like 300 units each, so you are talking about several hundred Rincon-sized buildings or a few thousand 50-100 unit buildings.