Numeric Parameters
Saving Energy
Geothermal HVAC systems are sustainable and can save a ton of energy. These systems can reduce the energy consumption of a building by up to 49%. You can see in the figure to the right, that the geothermal HVAC system cut an energy bill almost in half by producing 49% of the thermal loads. Below in Table 1, you can also compare the air emissions of geothermal systems to other heating fuel systems. As you can see, geothermal systems are the least harmful to our earth. In Figure 2, in an example of a building using a geothermal HVAC system, you can see that 53 tons of greenhouse gas emissions are saved per year compared to a conventional HVAC system.
Operating Costs
Geothermal HVAC systems also can save you money in operating costs. These systems have a much lower operating cost compared to other heating fuels. Cost savings can vary between 40 and 70% of existing heating and cooling expenses. You can visualze these savings in the figure to the left (Figure 3). You can also see in Figure 2, that in one example of a building using a geothermal HVAC system, The Argonne's Visitor Center, $4,000 is saved per year in heating costs. In Figure 4, you can see the cost comparison for 1 million BTUs. The cost for geothermal is the lowest at $8.79/million BTUs.
Figure 1
Figure 2
Figure 3
Table 1
Lifetime
Geothermal HVAC systems are extremely durable and have long lifespans compared to most HVAC systems. The underground parts of the system can last an everage of 20 to 50 years while the interior parts of the system can last an average of 25 years.
Figure 4
Figure 5
Ground Depth and Temperature
Depending on if the system is horizontal or vertical, it can be buried at different depths. Horizontal systems are usually buried between 4-6 ft in the ground while vertical systems vary from 50-500 ft in depth. The temperature varies at different depths at different times throughout the year. To visualize this, see Figure 5. As you can see, the further you get into the ground, the less the the temperature varies throughout the year.