door cores. A good core choice means you'll benefit from continual savings without adding to the original

cost of your hollow metal doors. Mesker has the information you need to figure how door cores affect your

energy costs. The graph below gives you an idea of which cores are more energy efficient. To estimate your

cost savings, you'll need to approximate the number of days you'll be using your heating during each

season. Your energy supplier also has helpful information to help you calculate your hollow metal door and

frame energy efficiency.

Using the cost of energy per 100,000 BTU from the graph above and the "U-Factor" information from the

table below, you can begin zeroing in on your energy cost per season when using a particular hollow metal

door core. Although figuring your summer cooling costs is a bit more complicated, many electric utility

engineers use this method to estimate local energy costs. Essentially, to determine your specific BTU loss,

take the square footage of your door (length times the width), multiplied by the U-Factor, multiplied by the

Degree Days, and multiplied by 24. The formula for determining your unit cost each season is kilowatt input

per ton of output, multiplied by the estimated hours of full load cooling, multiplied by the cost of a kilowatt

hour, multiplied by the difference between the desired temperature inside and the outside temperature,

multiplied by the square foot of your door's surface, multiplied by the "U-Factor" for your hollow metal door,

and divided by 12,000 (BTUs per ton).

**Door Summary Chart**

table below, you can begin zeroing in on your energy cost per season when using a particular hollow metal

door core. Although figuring your summer cooling costs is a bit more complicated, many electric utility

engineers use this method to estimate local energy costs. Essentially, to determine your specific BTU loss,

take the square footage of your door (length times the width), multiplied by the U-Factor, multiplied by the

Degree Days, and multiplied by 24. The formula for determining your unit cost each season is kilowatt input

per ton of output, multiplied by the estimated hours of full load cooling, multiplied by the cost of a kilowatt

hour, multiplied by the difference between the desired temperature inside and the outside temperature,

multiplied by the square foot of your door's surface, multiplied by the "U-Factor" for your hollow metal door,

and divided by 12,000 (BTUs per ton).

To learn more about building standards and guidelines for energy efficiency, we suggest you go to

www.ashrae.org, the website of the "American Society of Heating, Refrigerating and Air-conditioning

Engineers." Hollow metals doors can help improve your energy efficiency.

www.ashrae.org, the website of the "American Society of Heating, Refrigerating and Air-conditioning

Engineers." Hollow metals doors can help improve your energy efficiency.