Since the home was converted to net zero energy, the old 4 ton SEER 10 heat pump had been used very little. With all the changes to the house we were able to maintain a comfortable temperature without air conditioning. However, the humidity was too high. Some problems that high humidity caused included: furniture drawers sticking, salt not coming out of the shaker, and mildew.

After doing a manual J calculation, we were able to reduce the size of the unit from a 4 ton to a 2 ton unit. The efficiency was increased from SEER 10 to SEER 18. With the new unit we should be able to control the humidity and not blow the energy budget .