We’re often told about how affordable housing is, but there is a world inside of the world of housing affordability.

Housing, we often read, is currently in a promised land of affordability. Though not quite the ideal that it was in 2011 and early 2012, it would seem that we’re still amidst a golden opportunity for homeownership, what with low mortgage rates and competitive pricing combining for a once-in-a-lifetime chance to own. Indeed, according to NAR’s Affordability Index, housing is more affordable than at any time from the early ’90s through 2008.

However, as with all such narratives, the truth is a bit messier. Though certain consumers can certainly take advantage of today’s low mortgage rates, others are not so fortunate, and new Goldman Sachs research, covered recently by The Wall Street Journal, has brought those inconsistencies to light. Here are three ways that some consumers are being left behind:

1. “Marginal” Borrowers – The key factor in measuring housing affordability, Goldman Sachs stated in its research, is whether or not consumers can actually qualify for those low mortgage rates, meaning that they have enough equity for a 20 percent downpayment. If that’s not possible, then consumers are what Goldman labeled “marginal borrowers,” or consumers who lack the incomes and credit scores to take advantage of today’s golden affordability opportunity.

2. Higher Rates in Marginal Land – Because marginal borrowers lack those prerequisites, Goldman Sachs explained, they have to opt for FHA financing. Though there are many perks to FHA mortgages – more accepting credit standards and 3.5 percent downpayments chief among them – they also come with extra stipulations and extra costs in the form of insurance premiums. Once those costs are factored in, February’s average 30-FRM rate of 4.47 percent, for instance, jumps to 5.65 percent for an FHA borrower.

3. Higher Costs in Marginal Land – Those higher rates, naturally, translate to higher costs for marginal borrowers. How much more? According to Goldman’s research, assuming that monthly mortgage payments account for less than 15 percent of an average homebuyer’s income (per NAR’s Affordability Index), marginal buyers are actually paying closer to 23 percent, which is the historical average.  As the Journal summarized, “In other words, housing isn’t a screaming deal for marginal buyers, which could go a long way toward explaining their absence from the housing market right now.”

Of course, we don’t mean to be total downers here. It merits repeating that, should your clients have all their ducks in a row, there are still some fabulous opportunities out there for prospective homebuyers. But still, if you’re working with clients who match any of the aforementioned characteristics, it’s important to know how their homebuying experience may differ.