How Interest Rates Affect Your San Diego Home Purchase

Mortgage interest rates are the single most discussed topic among San Diego buyers right now — and for good reason. Rates have a direct, concrete impact on what you can afford, what your monthly payment will be, and whether buying makes sense today versus waiting. Here's how to understand the numbers so you can make a clear-headed decision.

How Rates Translate to Monthly Payments

The relationship between interest rates and your payment is more dramatic than most people realize. Here's what different rates mean on a $700,000 loan — a common loan size for San Diego buyers putting 10–20% down on a mid-range property:

The difference between a 6% and 7% rate on that loan is $458 per month — and roughly $165,000 more in total interest over 30 years. That's why rate movements matter so much.

How Rates Affect Purchasing Power

The flip side of the monthly payment equation is purchasing power — how much home you can qualify for at a given income and rate. As rates rise, the loan amount you can support on the same income shrinks meaningfully.

If a buyer qualifies for a $4,500 monthly payment (principal and interest):

• At 6.0%, that supports roughly a $750,000 loan
• At 6.5%, that supports roughly a $711,000 loan
• At 7.0%, that supports roughly a $675,000 loan
• At 7.5%, that supports roughly a $641,000 loan

A single percentage point increase in rates reduces purchasing power by roughly 10%. In San Diego's market, that can mean the difference between different neighborhoods or property types entirely.

Fixed Rate vs. Adjustable Rate Mortgages

30-Year Fixed

The standard. Your rate and payment never change for the life of the loan. Offers maximum predictability. The right choice for most buyers who plan to stay long-term and want protection against future rate increases.

15-Year Fixed

Significantly lower rate than a 30-year, but much higher monthly payment. Builds equity dramatically faster. Best for buyers who can comfortably handle the larger payment and want to own their home outright sooner.

Adjustable-Rate Mortgages (ARMs)

ARMs start with a fixed rate for an initial period (typically 5, 7, or 10 years), then adjust periodically based on market indices. A 7/1 ARM at 6.0% vs. a 30-year fixed at 7.0% saves significant money in the early years. ARMs make sense for buyers who are confident they'll sell or refinance before the adjustment period begins. They carry real risk if plans change and rates rise.

Buying Down the Rate ("Points")

One option many buyers overlook is paying discount points at closing to permanently reduce their interest rate. One point equals 1% of the loan amount ($7,000 on a $700K loan) and typically reduces the rate by 0.25%.

Whether paying points makes sense depends on your breakeven timeline — how many months of lower payments does it take to recoup the upfront cost? For a buyer planning to stay 7+ years, buying down the rate often makes financial sense. For someone uncertain about their timeline, it usually doesn't.

The Rate Lock

Once you're under contract, your lender will offer a rate lock — a commitment to hold your rate for a specified period (typically 30–60 days) while you complete the closing process. Rates can move meaningfully during escrow, and locking protects you from increases. Most buyers should lock as soon as their offer is accepted.

Extended locks (60–90 days) cost more but may be worth it in volatile rate environments or for longer escrow periods.

Should You Wait for Rates to Drop?

This is the question I get most often. The honest answer: rates are genuinely difficult to predict, even for professional economists. If you wait for rates to drop to 5%, you might wait years — or you might refinance in 18 months if they do drop. What you can't get back is time in the market.

San Diego home prices have historically appreciated faster than the cost of a slightly higher rate over a 5+ year holding period. Buyers who waited in 2022 and 2023 for lower rates often watched prices rise while rates didn't fall meaningfully.

Buy when you're financially ready and have found the right home. Refinance when rates improve. That's the most reliable strategy in San Diego's market.