[bangoimby]

> Building apartments and tearing down houses lowers the price of apartments and raises the price of houses; it's simple supply and demand.

Do you have evidence of this? I would think increasing the supply of housing would have a downward effect on all housing. Sure, if you're really set on a SFH and there are fewer of them, you'll have to compete. But I think people who want a SFH want a SFH _neighborhood_, and there's an unanswered question to what extent different types of housing can substitute for one another.

The value of _land_ may increase with zoning because development rights are still in limited supply, and the profit opportunity for a developer has gone up. But I don't see many SFH owners clamoring to let their neighbors on both sides be replaced with 5-over-1.

[quantumwannabe]

The housing market is not perfectly fungible. A three bedroom house is not replaceable with a studio apartment, and building a studio apartment would only lower the price of houses if there were a lot of people living in houses who would prefer to live in such an apartment. Generally the reverse is true, as more Americans aspire to own a house than live to in an apartment. This survey[1] shows this; look at the difference between live in city and want to live in suburb versus live in suburb and want to live in city. It's not a perfect proxy because many cities have houses and many suburban areas have apartments, but it should give you a general idea. This means that building houses may lower the price of apartments because there are people living in apartments who would prefer not to be. Once they move out, they open up a spot for someone who wants to live there. Three bedroom apartments are much less frequently built than 0-2 bedrooms (the smaller the floor plan, the more tend to be built), but there are still many intangibles like owning the land underneath your building and physical separation from neighbors that lead some people to prefer a house over an equivalently sized apartment/condo.

In addition, many suburban areas are not exclusively single-family houses; they already contain a mixture of apartment buildings and commercial areas, so I dispute your point that single family home buyers insist on exclusively single-family neighborhoods. In most suburban areas I've seen, the apartment buildings tend to cluster together, often near a commercial area, so if you're deep in a sea of houses it's unlikely that your next door neighbor will sell to a developer. People may not be excited if their next door neighbor sells to a developer who plans to build an apartment complex, but that doesn't change the value of their lot, which has increased because the developer is willing to pay more for it if they can build bigger buildings on it.

I was talking about a market with no rules restricting what can be built, and in such a market the neighbor has no say, so their personal opinion is irrelevant. The guy I was arguing with wanted restrictions on housing types he liked to be repealed, but wanted restrictions on housing types he didn't like to be enacted, and I was trying to point out that hypocrisy. Building houses versus apartments is a balancing act governed by demand, but market distortions like banning one type of housing or another can cause an undersupply of certain types of housing, which leads to an increase in prices for the type of housing that is undersupplied and for the substitute it's would-be buyers end up using.

[1] https://news.gallup.com/poll/245249/americans-big-idea-livin...

[bangoimby]

Didn't say it was perfectly fungible, just fungible enough that a significant enough increase in other types of supply might bring down SFHs. Either that or the true value of a SFH in a no longer housing constrained San Francisco really is $2.5 million.

If you believe that SFH buyers do not insist on SFH neighborhoods (whole cities are not neighborhoods), and should welcome denser zoning because it makes their lot more attractive for redevelopment, go circulate a petition for this among SFH owners and see how far it gets.

[quantumwannabe]

You're thinking far too narrowly on SF. In SF, there are people sharing a rented house and treating it as de facto apartments, so my argument still holds. Outside of college towns, that is normally a rare thing, so it isn't applicable for most metro areas that haven't been frozen in time for decades. The Bay Area is a terrible example because they've banned ALL types of housing, not just apartments. They have an urban growth boundary and haven't upgraded their infrastructure to support their growing population, which means that for a given commute time, people must live closer to work than they would with better infrastructure, which increases the number of bidders for each property near offices. I suspect though that even if enough apartments are built in SF so that single-family homes become single-family again, the price of a house there will still be millions. For example, look at the Upper East and West Sides of New York, where there are townhouses worth millions to tens of millions, just like there are in SF, but they are surrounded by massive apartment buildings. Those townhouses are also protected by zoning (In the local government's words: "R8B contextual districts are designed to preserve the character and scale of taller rowhouse neighborhoods."), and they'd be worth even more if a skyscraper could be built there. You could argue NYC still needs more apartments there, but the value of that townhouse's land would still be high, as the developer who wants to build another skyscraper with hundreds of units can afford to pay far more than all but the very richest potential homeowners. A regular New Yorker who wants a house, while they may be priced out of Manhattan, still has the option of moving to New Jersey or somewhere on Long Island and commuting in, as NYC sprawled in addition to building up. If they want to stay a homeowner in Manhattan (or a San Francisco) then they have to outbid the developers.

To your other point about insisting on SFH-only neighborhoods, in large parts of the country, there are apartment buildings and large commercial areas spread between and in single family neighborhoods, and that hasn't stopped people from buying houses there. I wasn't arguing that they all should support higher density zoning, just that it is in their financial best interest to do so. Another major problem is that because the Bay Area has refused to build anything for decades, it has decades of unmet (or to use urbanist language "induced") demand for houses, apartments, roads, transit, etc. that has to be met before prices and congestion will start to go down. To maximize housing affordability you need a mix of sprawl and density with appropriate infrastructure for the type housing built, and if you only do one type of growth you will have many people who are unhappy, which is why in another comment in this thread I accused the YIMBY urbanist of being the same as a NIMBY SFH owner, just with a different preferred housing type. The Gallup survey I linked earlier shows that there are more people currently living in cities (presumably in apartments) who wish to live in suburbs or rural areas (presumably in houses) than the reverse, so there is an unmet demand for "sprawl" and options like remote work.

My major point if a SFH owner in SF was purely motivated by money, they would welcome development on their land and wish to limit it on others'. Many of them aren't though, and they aren't lying or using euphemisms when they say they want the character of their neighborhood preserved. I hear tons of arguments that they are opposing multi-family housing because it would lower their property values, and that just doesn't make sense. A San Francisco with an apartment built for everyone there who wants one and no other changes would most likely still have million dollar houses, though the rent of the apartments would be less.