An ACTIVE Closed Loop System is appropriate for the area shown above. It provides 60% to 80% of water heating needs in moderate climate areas and 50% to 70% in colder areas. This system can also be designed to handle space heating needs. Closed Loop systems or drainback systems are required for freeze protection in areas where hard freeze months exit. Warmer climate performance is negatively affected by heat exchanger losses preventing it from being the best choice under these conditions.