Home heating and cooling systems consume more energy than any other home system, accounting for nearly one-third of a family’s utility bill. Geothermal HVAC has long been considered a highly efficient alternative, but it’s often overlooked, due to high up-front installation costs and space limitations. Adding ground-based geothermal required large open lots, where conventional drilling equipment could access and maneuver freely, a tall order in densely populated areas, or yards where established landscapes might be damaged.
Those obstacles, however, can now be overcome with technology known as sonic drilling. These drilling rigs are more compact and agile than their predecessors, allowing installers to squeeze into suburban yards and driveways.
Sonic drilling rigs are outfitted with weight-distributed rubber tracks that preserve grass and landscaping, while protecting hard surfaces like driveways, sidewalks and patios. In addition, sonic drilling rigs offer 360-degree movability. They rely on a vertical drill casing that minimizes the machine’s footprint so it can more easily retrofit existing homes with the ground loops that enable geothermal heating and cooling systems to work efficiently and effectively.
Compact drilling solutions reduce installation requirements and costs. If you’d like to see a case study, Ross Trethewey, host of This Old House, discusses sonic drilling on an episode dedicated to the equipment .
According to the US Department of Energy, geothermal heat pumps “can reduce energy use by 30%-60%, control humidity, are sturdy and reliable, and fit in a wide variety of homes.”
Geothermal heating and cooling typically replaces a home’s existing air conditioning and heating equipment with an electric-powered heat pump. This pump transfers fluid to and from underground pipes to either heat or cool the house, depending on the season and the climate.
Geothermal uses the natural stability of below-ground temperatures to provide a fossil-fuel-free baseline for the home’s indoor temperatures. Combine the geothermal system with renewable energy to power the pumps and electrical equipment, and the system easily becomes net zero.
To add geothermal to an existing home, planning is key. The installation, for example, doesn’t always need to happen simultaneously. For example, contractors may be better served to break up the work into three phases: drilling, system tie-in, and heat pump installation.
Another way to lower labor costs is to install more than one system at once. For example, if several neighbors want to upgrade their HVAC, drilling teams can complete multiple installations at one time. Keeping the rigs busy will keep costs down by enhancing efficiency and worker deployment.
Soil types and location also matter. Your geothermal contractor will need to do some research to understand a lot’s geology and soil type. Sonic drilling works best under certain conditions but is not designed for drilling through solid granite or other extremely dense materials.
Homeowners and builders should ask questions early and often, ensuring that they have the insights necessary to make the process as efficient and effective as possible.