Costly condos sell easily in rarefied air of Colorado

''The only way to go,'' says Charlie Gersback as he leans back in his chair at one of the world's newest and most expensive condominium hotels, ''is Rolls-Royce.''

It was the grand opening of the first luxury condominiums at Colorado's newest resort, Beaver Creek, and an announcement had just been made that 21 units were optioned to one buyer from New Jersey at a retail price of $400,000 to $600,000 - that's per unit.

Mr. Gersback, a broker, was referring specifically to what many developers and real estate salesmen perceive as the effect of tougher environmental standards in recent years in the Colorado Rockies: more zoning controls, better-quality construction, and consequently higher prices.

To open Beaver Creek last winter, it cost Vail Associates more than $30 million and eight years of planning to overcome the environmental hurdles.

By the time the resort is completed, nearly $500 million is expected to be invested.

To link Colorado's meteoric escalation in prices for prime resort properties to strengthened environmental controls, however, is a bit like laying today's gasoline prices to the cost of modifying gas-pump gauges from triple to quadruple digits.

The fact is that jet travel and Rocky Mountain sun and snow have been beckoning the very wealthy to buy choice home sites at ever-soaring prices - at least until now.

They have come not only from Texas, Chicago, and California, but from the far corners of the hemisphere.

Until last winter the stream of willing second-home condominium buyers appeared to be endless. But last year the snows faltered. And while the snows again returned this past winter, the stream of condo buyers and skiers seems to have slowed.

That is not to say it has stopped, by any means, if you are talking about the ''high end'' of the market. In this rarefied air, ''high end'' refers to any condo over $400,000 which, in Beaver Creek's new Charter condominiums, breaks down to an average of $375 a square foot.

Many of the luxury units, which generally run from 1,100 to 1,200 square feet with two bedrooms, but can be as large as 2,200 square feet, are considerably more expensive than that. And in the neighboring Centennial condo project, yet to be completed, a penthouse condo has been sold to a wealthy Texan for $1.15 million.

Is the Colorado resort-land boom recession-proof, then?

It is not, say many real estate people here. ''We thought so, but that's a myth,'' acknowledges John Ahearn, a marketing consultant in Steamboat Springs.

Generally, sales are flat or have actually retrenched, observes Bob George, an Aspen real estate executive. But the high end, while having lost some of its momentum, is still very good. In the 12-month period beginning Dec. 1, 1980, Pitkin County, which contains Snowmass and Aspen and is under a controlled-growth plan, recorded $251 million in real estate sales.

Pitkin County has the highest median home value in the entire nation ($200, 000 or more), according to a government report issued in November.

At Beaver Creek the image being artfully projected is not only ''high end,'' but la creme de la creme.m Of a planned 158 units, which are to be sold for a total of $70 million, 90 were presold before construction.

Buyers are being sold condominiums, not investments, observes John Edwards, a consultant to the developer of the Charter project, Heritage Financial Corporation of Denver.

''We've found that for most of our owners this is not their first second home ,'' he adds. ''Many already have second homes in Palm Springs, Palm Beach, and other spots.''

Mr. Edwards estimates that perhaps as many as one-quarter of the owners won't even put their half-million-dollar units into the rental pool.

Nevertheless, one Eastern investor-cum-skier has obtaineed a block of 21 condominiums for what is to be a negotiated price. Apparently, the Rocky Mountain real estate boom still has a lot of bang left in it.