More homeowners are embracing alternative energy systems – Baltimore Sun


December 15, 2016 Facebook Twitter LinkedIn Google+ Uncategorized


When Drew Derrick and his family decided they wanted to add central air conditioning to their 200-year-old Catonsville home, they had a number of options.

They decided on a geothermal system in which the earth’s constant 55-degree below-ground temperature can be tapped for cooling and heating.

The system — which required the drilling of three 430-foot-deep wells in the front yard, piping and ductwork — was completed in July.

For the next month, they cranked up the air conditioning. With the addition of central air to cool the entire house, their utility bill was $20 higher than the month before, when they had window units cooling only parts of their home.

Drew Derrick has recommended geothermal systems to others but admits costs can be prohibitive without incentives. Congress has yet to renew a tax credit for geothermal systems.

“If the federal rebate goes away, it’s going to be harder and harder to warrant people getting these systems installed,” he said. “The cost is twice as much and without that 30 percent off and those other rebates, it’s just not going to be affordable to an average person.”

How they work

Solar panels

Solar panels, typically installed on roofs, absorb light from the sun to generate electricity. Photovoltaic cells in the panels convert it to direct current electricity. An inverter converts it to alternating current electricity. An electrical panel sends power to whatever in the home needs electricity, such as appliances or lights. A utility meter tracks how much is used and how much extra power is sent back to the grid, or network of existing power lines. Some power can also be stored in batteries.

Geothermal systems

While the temperature outside changes over the course of the year, it remains more constant underground.

In the winter, a ground loop — underground pipes that connect to a heat pump — circulates water which absorbs heat from the ground and sends it to the indoor heat pump. The heat pump takes the heat from the liquid and is supplemented by an electric heat pump for additional warmth.

In the summer, the process is reversed. The heat pump takes the hot air from inside the home and removes the heat, leaving behind cool air to be circulated as air conditioning. The removed heat from the air is sent into the earth through the ground loop.

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