Show HN: I built a dashboard to compare mortgage rates across 120 credit unions

But part of that is because people who would otherwise want to sell their house are choosing NOT to, because they don't want to lose their great mortgage. If we didn't have these long, fixed rate, mortgages, there would be a lot more housing liquidity and prices wouldn't be so inflated.

Now, there is a cycle of "rates go down, there is a flurry of re-finances and everyone locks in the lower rates and new buyers enter the market, and housing prices go up and up", and then rates go up, but housing prices don't go down because people can't afford to buy the houses at the same prices anymore, and so no one wants to sell (because the current owners are paying below market rates for their mortgage, so they face no selling pressure like they would if there WEREN'T long term fixed rate mortages), so there is no decrease in prices.

Home prices are probably higher now than they would be due to the limited supply due to people being locked into house.

You still can with certain types of mortgages.

> Do 30-year mortgages make the other houses more expensive somehow?

OP didn't mean to say this, but yes, unfortunately they do. Anything that "increases affordability" will result in an eventual increase in the principal value for things that are supply constrained.

I appreciate the good deal we have, but my point is that long term fixed mortgages really complicates the housing market and can make it so you are stuck where you are, especially if you buy a house when rates are low.

Think about what happens. My wife and I wanted to buy a house. Our budget is mostly around what we can afford as our monthly payment, just like everyone else. That means if interest rates are low, we can afford a much more expensive house (obviously). Ok, so we buy one with a payment we are comfortable with.

Now, rates go up. Say we need to move for a job, so we need a new house, and we still have the same budget. Well, that means the total cost of the house we can afford is much lower, because the higher interest rates means the total loan value must be much smaller to keep our monthly rate the same. If we were first time buyers, this is fine, because everyone is in the same boat; everyone has a smaller budget because monthly payments on the mortgage are higher, so housing prices should be lower. If that is the case, though, it means the house we are trying to sell won't sell for as much (because mortgages for house will cost people more), which means we would end up taking a loss on our mortgage (because even though our monthly payment is the same as the new loan, the total value of the old loan is a lot higher).

Of course, prices for houses don't move nearly as much when interest rates change as they should (relative to mortgage purchasing power). This is for many reasons, but part of it is because when rates are high, people (like me) don't want to sell their house and have to lose their really good mortgage, so fewer houses are on the market, which inflates prices. When rates go down, more people want to buy and sell houses, because they can both get more for their house they are selling and they can afford bigger mortgages on their new houses, which inflate prices.

Basically, this lack of mortgage liquidity works to keep housing prices high. When rates are high, no one wants to sell OR buy, and when rates are low, everyone wants to sell AND buy. Both result in prices being high.

30 year fixed mortgages are just a really weird financial product that has all sorts of market disrupting effects. You can pre-pay them whenever you want, so when rates are low, high rate loans are paid off and low rate loans replace them, but that means no one wants to sell their house and lose their great loan when rates are high. This means housing prices soar when rates are low, but don't come back down when rates are high. It creates a ratcheting effect on house prices, which is why so few people are able to buy houses.

This continues until the entire market collapses, like it did in 2007, and then the process repeats.

It would be difficult. Mortgage interest is deductible from your taxes (up to a point), but only if it is your primary home. If we moved, we would have to pay a lot more in taxes.

The mortgage tax deduction is another thing that drives up home prices.

I still don't understand how this means you "can't afford to sell your house." It just means you can't afford to buy another house at the same price as the one you have now. That's a different problem, and one that doesn't actually have anything to do with the interest rate on your existing mortgage. You can't afford to buy a house today at the same price that you could on the date you closed on your current house, but that's true regardless of the interest rate on the current house.

Let's put a number on it. Since the article uses $400k as a reference point, let's use that. You could afford to buy a $400k house back when you bought your current house. You cannot afford to buy a $400k house today. That would be true whether or not you had purchased your current house, and regardless of the interest rate on its mortgage if you had.

You only "can't afford to sell your house" if you're underwater on the mortgage and can't come up with the money to sell it.

You are locked in because currently you have a great deal that you don't want to lose. If you were in Australia, you would already be paying that higher interest rate for your current house. I don't see how that's a downside.

That's very similar to not being able to change jobs because you cannot find another job that pay even 66.6% as well as your current one.