I have attached a simple little spreadsheet that allows you to examine the inter-relation of the parameters that make up the rent vs. buy equation.
Running through them, these are:
Buying Parameters
* Initial Price of house (shown at 200k)
* Initial Deposit (shown at 10%)
* Mortgage interest (shown at 6%)
* "Receive", which is the money available for investment that year. This has an initial value (shown at 10,800, i.e. the cost of the interest in year 1) and an inflation rate (shown at 3%)
* House price inflation (shown at 2%)
Rental Parameters
* Initial rental yield (shown at 4%)
* Rent increase (shown at 3%)
* Interest earned on alternative investment (shown at 8%)
The columns from left to right are:
* Year
Buying
* House value at start of year
* Mortgage at start of year
* Interest paid on mortgage
* "Receive", i.e. income that will be used to pay interest and reduce mortgage
* Mortgage at end of year
* House value at end of year
* "Running Value", i.e. the value of the capital at year-end.
Renting
* Savings at start of year -- initially this is equal to the deposit
* "Receive", i.e. income that will be used to pay rent and invest. This is same as the "Receive" under the "Buying" option.
* Rent
* Interest received on savings
* Savings at year-end.
It's easy to come up with perfectly reasonable scenarios under which you are better off after 5 years if you buy. And it's easy to come up with perfectly reasonable scenarios under which you are better off after 5 years if you rent.
The rental option has an apparent disadvantage, in that the investment under the purchase option is geared. That means that with just a 10% deposit, for every 1% the house increases in value, the capital value increases by 10%.
This increases the risk of investment though. To compare like with like, it really should be compared with a similar geared investment under the rental option. I'm throwing this up as a caution now, because it explains why a 10% growth in savings is so poor compared with a 5% increase in house prices -- you aren't really comparing like with like.
By playing with the numbers, you'll see that although the homeowner stands to gain much more if house price inflation is high, he also stands to make giant losses if house price inflation is negative.
So sure, if we envisage a world in which house prices always zoom up then it appears that the heavily geared homeowner is always much better off. But investments always come with a risk. This thread is a prime example of that risk -- lots of people think that house prices will reduce. And the homeowner is choosing to buy into that risk and choosing to do so with a leverage most businesses would run a mile from. It's hardly a surprise that in a high inflation environment they do better than the renter. But they get the downside risk along with that upside.