VENTILATION AND IAQ
Be sure the heating system accounts for the facility’s ventilation and indoor-air-quality requirements. For example, high-efficiency indirect gas-fired boilers, unit heaters and air-turnover systems that only heat recirculated indoor air provide no building ventilation. The same is true for radiant heating systems, which have no blowers and provide no ventilation. When a mechanical exhaust system is used, the warehouse can be starved for make-up air. This creates a constant path of cold-air drafts when dock doors are open or renders the exhaust system ineffective when the building is closed tight. Building studies by Cambridge Engineering, Chesterfield, Mo., and energy modeling by GARD Analytics, Arlington Heights, Ill., confirm high-temperature-rise direct-fired blow-thru space heaters can be an energy-efficient solution for these problems and can save energy by reducing the total heating load.
REDUCE STRATIFICATION
Save energy by reducing temperature stratification in warehouses with high ceilings. Heating systems that provide significant air movement will reduce stratification and provide more uniform temperatures throughout the building. Building studies by Cambridge Engineering show direct-fired blow-thru space heaters with high-velocity vertical-throw diffusers can achieve 3 to 5 F temperature variation, which is the same or better than large air turnover systems while using less energy. (See the corresponding white paper at www.cambridge-eng.com//EMWhitePaper.pdf.) Radiant heaters and ceiling fans are other potential solutions.
ASHRAE 90.1 COMPLIANT
Heating equipment should at a minimum be compliant with ASHRAE Standard 90.1, “Energy Standard for Buildings Except Low-Rise Residential Buildings”. This does not necessarily ensure you are getting the most energy-efficient heating system but it is a requirement for many government tax incentives and utility rebate programs. The heater manufacturer should have this stamped on its nameplate.
If a warehouse heating system is more than five years old, less than 80 percent efficient and you qualify for an EPAct tax deduction, then a warehouse retrofit using energy-efficient heating equipment, such as blow-thru space heaters, is really a “no brainer.”
DOCUMENTED ENERGY SAVINGS
Because actual energy savings is the goal, use a proven warehouse heating technology from an experienced manufacturer that can document energy savings with utility bills, studies of existing buildings and energy modeling.
An industry energy-modeling white paper is available from Cambridge Engineering that documents the energy used by seven warehouse heating/ventilating systems. In the white paper (www.cambridge-eng.com/pdf/EMWhitePaper.pdf), building studies and energy modeling by an independent consultant show blow-thru-type space heaters use the least amount of energy to heat and ventilate warehouses larger than 25,000 square feet. Energy-performance guidelines from this white paper can be used for obtaining utility rebates and EPAct tax deductions. In addition, ask your contractor about warehouse space-heating equipment that is prequalified for EPAct tax deductions when used in eligible facilities. This could simplify the process for getting significant tax benefits.
If a warehouse heating system is more than five years old, less than 80 percent efficient and you qualify for an EPAct tax deduction, then a warehouse retrofit using energy-efficient heating equipment, such as blow-thru space heaters, is really a “no brainer.”