Why is there lack of consensus over the issue of system sizing?
AMost consumers will receive excellent performance and savings with an EE unit that is designed to provide 70-75% of the total heat loss for the building. When ambient temperatures are above the design balance point, the EE unit will provide all heating required; only when outdoor temperatures drop below that point does the EE unit require supplemental heat from an electric resistance heating element inside the unit. Most outdoor winter temperatures are above the balance point, and the EE system can provide 95% of the load if the unit is sized to 70%. Some dealers prefer to install a system that meets 100% of heat loss; this eliminates the need for supplemental heating but increases the cost of installation (more pipe is required).
