do we really need a heat exchanger

we are building a 52'x28' timberframe. we were just informed by our stress skin panel supplier that if we don't install a heat exchanger our warrenty will be void. we got to bids on heat exchangers and they came in at $5000.00! The house is in Utah at 5000 ft elevation and our humidity is in sigle digits 90% of the time. We were even planning on installing a humidifier for our dry skin and for our timberframe and homemade wood funiture. Do we really need a heat exchanger in the dry west? What is it's true purpose? Can we do it cheaper than $5,000? Any help you can provide is appreciated.
Thanks,
Paul Klason and Cheryl Prawl

Paul:

I believe you are correct in identifing the issue as humidity control. Empirical evidence has show that the excess (over ambient) moisture generated inside the house will alway escape somewhere. Prior to the practice of foaming all the panel joints, this would always occur near the source of moisture (like bathrooms and kitchens). The result was rotted panel skins in an alarmingly short period. Even if all the panels are installed and foamed properly, the moisture will escape near it's source. Thus, the manufacturers are suggesting the heat exchanger to spread the humidity around rather than to provide a source of it. You might be able to conform to the warranty requirements with some sort of local air/humidity control in bathrooms and kitchen, but I don't know if this could be done more cheaply than with a single whole-house system.