Mortgages. Get ’em while they’re hot. Err, “cheap.”

Financing costs for half-million dollar human self-storage compartments (hat tip to a reader for that little quip) fell a fourth straight week, the MBA said Wednesday.

The rate on a 30-year commitment to a tiny plot of land with a small-ish box on it is now just 6.44%, the lowest since April of last year.

Rates still aren’t anywhere near low enough to catalyze a market thaw. As discussed here earlier this week, six out of seven US mortgages have rates below 6%.

Tellingly, the latest decline wasn’t accompanied by a meaningful increase in application activity. Refis actually fell versus the prior week, although the index was obviously much higher versus the same week a year ago. Recall that this time last year, US Treasurys were grappling with a sharp term premium repricing on the heels of the Fitch downgrade.

The MBA’s purchase index rose 1% from a week ago on a seasonally adjusted basis. On an unadjusted basis, it fell 1%.

“As observed in recent weeks, despite lower rates, purchase applications have not moved much,” MBA VP Joel Kan sighed. “Prospective homebuyers are staying patient now that rates are moving lower and for-sale inventory has started to increase.”

Yes, would-be buyers are “staying patient.” They’re also chasing the elusive target. Or trying to catch a moving train, if you like. While it’s good news that rates have come down (and fairly dramatically at that), the ongoing increase in prices means getting to the 20% downpayment threshold is harder.

The figure above, utilizing Redfin’s data, shows the average downpayment in the US just hit a new record near $68,000, up 15% YoY.

That growth rate is considerably faster than price appreciation on the typical home, which means buyers are trying to force down their monthly payments, even if it means going deeper into their cash cushions.

“Traditional buyers are putting down large down payments to try and lower their mortgage payment,” a Denver agent told Redfin’s Mark Worley, for an article published Wednesday.

As a share of the purchase price, the typical downpayment’s now the highest in over a decade. And yet, at 18.6%, it’s still not enough to avoid PMI.

If you’re wondering whether the average young family in America actually has $68,000 in cash, the answer’s apparently “no.” “These buyers will often utilize the help of family members to put down more than they could on their own,” the same Redfin agent said.

I wonder what the rate on those loans is.