I don't think the question was about the investment as much as the analysis process.
When I run a projection like this, I like to make it kind of a "what to expect in the first year" scenario.
I also include projected tax benefits, equity buildup (amount of principle paid) and somtime include some estimation of appreciation.
So, using your numbers (and a couple of my own assumptions), this is what I get:
Your Assumptions:
Purchase Price $250,000.00
Down Payment $50,000.00
Loan Term 30 years
Loan Rate 7.80%
Yearly Income $33,495.00
Yearly Expenses $11,412.00
My assumptions:
Property Appreciation 3.00%
Buyer's Tax Bracket 30.00%
Depreciation-
Land 20.00%
Building 65.00% over 27.5 years
Personal Property 15.00% over 5 years
1st Year Benefits:
Cash Flow
$33,495.00 Income
- $11,412.00 Expenses
= $22,083.00 Net Operating Income
$1,439.74 Monthly Payment
* 12 Months
= $17,276.89 Debt Service
$22,083.00 Net Operating Income
- $17,276.89 Debt Service
= $4,806.11 Cash Flow
Tax Shelter
$22,083.00 Net Operating Income
- $5,909.09 Building Depreciation
- $7,500.00 Personal Property Depreciation
- $15,538.73 Interest Paid
$-6,864.82 Taxable Income / Loss
$-6,864.82 Taxable Income / Loss
* 30.00% Tax Bracket
$2,059.45 Total Tax Effect (You save this much in the first year on your taxes...)
Equity
In the first year's payemts, $1,738.16 of principle will be paid.
Appreciation
A property worth $250,000.00 whose value increases by 3.00% per yer will increase in value by $7,500.00 in the first year.
Total Benefit
Cash Flow + Shelter + Equity Increase + Appreciation = $16,103.71
32.21% return on down payment
If you don't like to include Appreciation, then you get
Cash Flow + Shelter + Equity Increase = $8,603.71
17.21% return on down payment