Pre Heat is the practice of heating a building above its normal setpoint during off-peak hours to reduce heating demand during peak pricing periods. This strategy leverages thermal storage in the building structure and stored hot water to minimize heating system operation during high-cost peak periods. Pre heating is commonly used in commercial facilities with time-of-use electricity rates.
Technical Details
Pre heating typically raises indoor temperature 2-4 degrees above normal setpoint during off-peak hours, usually between midnight and 6 AM. The building envelope and thermal mass absorb and retain this heat for gradual release throughout the day. Setpoint adjustments commonly range from 72°F to 76°F during pre-heating windows. Boiler systems and heat pumps operate during low-rate periods to charge thermal storage.
Practical Applications
Pre heating is particularly effective in buildings with significant thermal mass and in climates with moderate heating requirements. Office buildings, educational institutions, and manufacturing facilities benefit from this approach. Combined with weatherization improvements, pre heating results in optimal performance.
Cost Savings
Facilities implementing pre heating report 12-20% reductions in peak demand charges. The strategy works best when integrated with automated building management systems that respond to utility rate signals.