PMI, Points, or 20% Down on a $620K Seattle Home at 6.65%: Which Mortgage Strategy Wins Over 10 Years
PMI, Points, or 20% Down on a $620K Seattle Home at 6.65%: Which Mortgage Strategy Wins Over 10 Years
You're in Seattle. A 3-bedroom in Beacon Hill just listed at $620K. You have $62K saved — exactly 10% — but your lender is pitching you two options: put 10% down and pay PMI, or buy down the rate with points to keep the payment manageable. Meanwhile, your financially cautious sibling is telling you to wait until you have 20% down and skip the PMI entirely.
Three paths. Three wildly different 10-year cost profiles. Which one actually wins?
Let's run the numbers — all of them, not just the mortgage payment.
Why the Rate Environment Matters Right Now
According to NerdWallet's April 13, 2026 rate data, 30-year fixed rates have been edging lower, offering some relief after months of elevated borrowing costs. But the relief isn't structural — it's fragile. A Realtor.com analysis published this week flags a sobering macro backdrop: rising U.S. national debt is likely to keep downward pressure on rates limited, because Treasury yields and mortgage spreads tend to track fiscal concerns over the long run. The Federal Reserve has limited tools to offset what bond markets do independently.
Translation: rates may tick down a few basis points week-to-week, but expecting a return to 4% rates to bail you out is not a plan. For this analysis, we'll use 6.65% — a realistic 30-year fixed rate in the current window, reflecting the mild downward drift while anchoring to where markets are pricing risk.
The Baseline: What $620K Actually Costs at 6.65%
Before comparing strategies, you need to know the true monthly cost of ownership — not just the P&I line on the mortgage app. Here's the full picture with 20% down ($124K):
Loan amount: $496,000
Monthly P&I at 6.65%: $3,184
Property tax (King County, ~1.0%): $517/month
Homeowners insurance: $150/month
Maintenance reserve (1% annually): $517/month
Total true monthly cost (20% down): $4,368/month
That's already $1,400+ more than the average Seattle 3-bedroom rent of approximately $2,900/month. We'll come back to that gap. First, let's look at what changes if you go in with 10% down instead.
Path A: 10% Down + PMI
With $62K down, your loan jumps to $558,000. Monthly P&I rises to $3,582. But the bigger hit is PMI.
At 90% LTV, PMI typically runs 0.65–0.80% of the loan balance annually. On $558K, that's roughly:
PMI: $302–$372/month (let's use $335 as a midpoint)
That PMI doesn't disappear until you hit 80% LTV — which at normal amortization speed and 3% annual appreciation, takes approximately 5–6 years.
True monthly cost (10% down + PMI):
| Line Item | Monthly Cost |
|---|---|
| P&I ($558K at 6.65%) | $3,582 |
| PMI | $335 |
| Property tax | $517 |
| Insurance | $150 |
| Maintenance reserve | $517 |
| Total | $5,101 |
That's $733/month more than the 20% down scenario — and $2,201/month more than renting. PMI alone costs you $20,100 over 5 years before it falls off.
This is the kind of analysis Torvani runs for you automatically — it doesn't just show the mortgage payment, it shows the full stack.
Path B: 10% Down + Buying Points
Your lender's alternative: keep the 10% down, but buy mortgage points to reduce the rate. Assume you spend 2 discount points (2% of $558K = $11,160) to bring the rate from 6.65% down to approximately 6.15%.
At 6.15% on $558K:
Monthly P&I: $3,400
PMI (still at 90% LTV): ~$302/month
Monthly savings vs. Path A: $3,582 − $3,400 = $182/month
Break-even on points cost: $11,160 ÷ $182 = 61 months (5.1 years)
So buying points only pencils out if you stay in the home — and don't refinance — for more than five years. If rates drop to 5.75% in year three and you refinance, you've paid $11,160 for a rate you're about to replace. The points money is gone.
True monthly cost (10% down + points):
| Line Item | Monthly Cost |
|---|---|
| P&I ($558K at 6.15%) | $3,400 |
| PMI | $302 |
| Property tax | $517 |
| Insurance | $150 |
| Maintenance reserve | $517 |
| Total | $4,886 |
Better than Path A by $215/month — but only after you've recouped $11,160 in upfront costs. And you're still paying PMI.
The Year-1 Amortization Reality Check
Here's the number that surprises most buyers. In year 1 on the 20% down scenario ($496K at 6.65%):
Total P&I paid in year 1: $3,184 × 12 = $38,208
Interest portion: $496,000 × 0.0665 = ~$32,984
Principal paid down: ~$5,224
That means 86% of your first year's mortgage payments go to interest, not equity. You're not building equity fast — you're front-loading the lender's return. This is why the first five years of ownership are the most expensive on a per-equity-dollar basis, and why buying in a market where you might move in 3 years is a real financial risk.
For a detailed breakdown of how amortization and points interact on high-balance loans, our Los Angeles $750K true monthly cost analysis covers the same mechanics at a higher price point.
The Refinancing Question
The rates-edging-lower headline raises a natural question: should you just buy now at 6.65% and refinance when rates drop?
The math on refinancing is often glossed over. Here's what it actually looks like:
Assume rates fall to 5.75% in 2 years and you refinance your $496K loan:
New P&I at 5.75%: ~$2,893/month
Monthly savings: $3,184 − $2,893 = $291/month
Refi closing costs (2–3% of balance): ~$12,000
Break-even: $12,000 ÷ $291 = 41 months (3.4 years)
So refinancing only recovers its costs if you stay in the home at least 3.4 years after the refi closes — meaning you need to stay in the home for 5+ years total (2 years before refi + 3.4 after). If you're not confident in that timeline, the "buy now, refi later" strategy costs you thousands.
And that's assuming rates actually fall to 5.75%. The Realtor.com national debt analysis makes clear that structural rate relief — the kind driven by lower Treasury yields — depends on fiscal conditions that aren't improving in the near term.
The Opportunity Cost of That Extra $62K
Here's what the 20% down path actually costs you beyond the down payment itself — the $62,000 you don't invest by going from 10% to 20% down.
At an 8% average annual S&P 500 return over 10 years:
$62,000 × (1.08)^10 = $62,000 × 2.159 = $133,858
Opportunity cost (foregone market gains): ~$71,858
Meanwhile, Path A (10% down) costs you roughly $20,100 in PMI over 5 years before it drops off.
Net comparison: investing that $62K difference and paying PMI for 5 years leaves you ~$51,758 ahead versus locking it into a larger down payment — assuming the S&P 500 performs at its historical average.
That's not a guaranteed outcome. Markets drop. But it's the number that belongs in the analysis. We covered the same tradeoff in depth for Denver buyers in our Denver $80K down payment opportunity cost post — and the mechanics are identical here, just at a higher price point.
So How Does Renting Stack Up?
Seattle median rent for a comparable 3-bedroom: ~$2,900/month.
| Scenario | True Monthly Cost | vs. Renting |
|---|---|---|
| 20% down, 6.65% | $4,368 | +$1,468/month |
| 10% down + PMI | $5,101 | +$2,201/month |
| 10% down + points | $4,886 | +$1,986/month |
| Renting | $2,900 | baseline |
The renting premium in Seattle is real and large. You're paying $1,468–$2,201/month more to own, depending on your down payment strategy. That's not "throwing money away on rent" territory — that's the rent option saving you money on a monthly basis.
Ownership wins over time if two things happen: the home appreciates meaningfully, and you stay long enough to recoup transaction costs (typically 8–10% round-trip when you factor in agent commissions, closing costs, and the front-loaded interest penalty). In Seattle — where the existing-home sales market has slowed materially, with NAR data showing a 3.6% drop in March 2026 to a 3.98 million annual rate nationally amid weak job growth and record high prices — appreciation is not a certainty in the near term.
You can model your specific break-even timeline at Torvani, where you enter your actual rent, down payment, and expected tenure.
The Wildcard: What a PMI Removal Triggers
One underappreciated aspect of the 10% down path: when PMI drops off in year 5–6, your monthly cost suddenly falls by $302–$335. That's a de facto "raise" in cash flow — and if you redirect it into extra principal payments, you meaningfully accelerate your payoff timeline and reduce lifetime interest. The math actually improves on Path A and B over a 15–20 year horizon, even accounting for the PMI years.
This is why simple comparisons ("just put 20% down to avoid PMI") miss the full picture. PMI is a cost — but it's a finite, calculable cost that buys you optionality when you have a better use for $62,000 in the near term.
The Bottom Line for Seattle Buyers in April 2026
There is no universally correct answer here. But here are the decision rules:
- 20% down wins if you have the capital, plan to stay 10+ years, and want the cleanest monthly cost profile.
- 10% down + PMI wins if your $62K earns better returns deployed elsewhere and you can comfortably carry the higher monthly payment.
- Buying points only wins if you're confident you won't refinance or sell within 5 years — otherwise you're paying upfront for a rate you'll replace.
- Renting wins if your timeline is under 5–6 years, your city's price-to-rent ratio is stretched (Seattle's is), and you want to preserve the optionality that comes with not having $124K+ locked in a single illiquid asset.
For the full picture on what hidden ownership costs look like in comparable high-cost markets, see our Phoenix $480K true monthly cost breakdown — PMI, points, and HOA fees all in one place.
Your variables — your rent, your savings, your timeline, your risk tolerance — determine the right answer. The math is tractable. Run it before you decide.
Torvani lets you plug in your actual numbers and get the full 10-year comparison: true monthly cost, break-even timeline, and opportunity cost, all in one place — no spreadsheet required.
Sources
- The Tax-Free Way To Generate Liquidity Without Risking Your Residence — Realtor.com News
- Mom-and-Pop Investors Own Far More Homes Than Big Investors—and May Benefit Most From Crackdowns — Realtor.com News
- America’s Rising Debt Could Keep Mortgage Rates High—and Housing Expensive — Realtor.com News
- Mortgage Rates Today, Monday, April 13: A Little Lower — NerdWallet
- Home Sales Fell in March as Weak Job Growth Dampened Buyer Confidence — Realtor.com News