Does buying a home actually build more wealth than renting over 15 or 30 years? You compare real prices for recently sold and rented homes and apartments in the same area. Then you model four annual salaries from $24,000 to $60,000.
For each income level you calculate mortgage payments at different down payments. You also factor in bills, salary growth, rent increases, and property value changes. A 15-year mortgage and a 30-year mortgage are both tested.
The results show that purchased apartments build the most wealth over time. Rented homes build the least. A higher down payment sharply reduces the total interest paid.
Hypothesis
The hypothesis is that buying an apartment will be the most economical option, followed by renting an apartment, buying a house, and renting a house.
Money grows on both your savings and the interest already added — and that same logic applies to long-term wealth decisions like buying versus renting. This project models mortgage payments at different down payments across 15-year and 30-year terms, using real prices for recently sold and rented homes and apartments in the same area. When you factor in salary growth, rent increases, and property value changes over those long periods, small early differences in down payment or loan length compound into large wealth gaps. The results show that purchased apartments build the most wealth over time, while rented homes build the least — and a higher down payment sharply reduces the total interest paid.
A complex financial decision becomes testable when you copy it into equations. You model four annual salaries from $24,000 to $60,000, then calculate mortgage payments at different down payments for each income level. Factor in bills, salary growth, rent increases, and property value changes, and you have a math-based copy of household finances. Running that model across 15-year and 30-year timeframes reveals which choices build the most wealth — answers you could never get by guessing.
Each monthly mortgage payment splits between paying down what you owe and covering the bank's interest fee. This project puts that split to the test by comparing a 15-year mortgage against a 30-year mortgage across four annual salaries ranging from $24,000 to $60,000. As down payment amounts increase, the total interest paid drops sharply — a direct consequence of how amortization distributes costs over time.
Method & Materials
You will gather data on recently sold and rented apartments and houses in the same area, size, and number of rooms. You will also gather data on bills and expenses from 15 families with five members. You will then calculate the mortgage rate, rent increase, salary increase, savings, and property value increase.
You will need data on recently sold and rented apartments and houses in the same area, size, and number of rooms. You will also need data on bills and expenses from 15 families with five members. You will also need to calculate the mortgage rate, rent increase, salary increase, savings, and property value increase.
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The results showed that buying an apartment was the most economical option, followed by renting an apartment, buying a house, and renting a house. 15-year mortgages were cheaper, and a down payment lowered the lost money from interest significantly.
Why do this project?
This science project is interesting because it looks at the financial decisions of buying and renting a house from different incomes and helps to determine which is the better option.
Also Consider
Experiment variations to consider include looking at different down payments and different mortgage lengths.
Full project details
Additional information and source material for this project are available below.
