Case Study #3: Long-Term Comfort, Lower Operating Costs and Reduced Carbon Emissions
- jahaugh
- Mar 14
- 3 min read
CASE STUDY #3: Tom and Lucia’s journey to bring down heating and cooling costs and reduce their household greenhouse gas emissions. Geothermal system played a big role!
When Tom and Lucia built their Acorn Deck House in 1998, they started with a design well-suited to becoming fossil fuel-free: tight construction, very good insulation and windows, and passive solar. The household initially used fossil fuels for cars, heating, hot water and cooking, but Tom and Lucia are well on their way to eliminating all of those.
Solar First!
In 2007, Tom and Lucia installed solar electric panels✳ on their roof, significantly reducing their electricity bills. They also added solar thermal panels✳ to pre-heat their hot water, saving on propane. Extra attic insulation✳ recommended by MassSave helped with heating costs.
In 2012 some of their solar power began flowing to their cars as they began the transition to electric vehicles.✳ A Level 2 charger✳ installed in their garage makes charging easy.
Superefficient Geothermal System Cut Heating Costs in Half
Next up was a big step! In 2018 they installed a ground source (geothermal) heat pump✳ to replace their forced-hot-air oil furnace. Geothermal systems draw heat from the ground in the winter to heat a home and dump heat there in the summer when cooling. Because they are pulling heat from the relatively warm ground, they are much more efficient in winter than air source heat pumps, which have to contend with far colder conditions. Even including the extra electricity used by the new system, Tom and Lucia reduced their heating bills by 50%.
Existing ductwork made the transition to geothermal easy and the air-handler for the geothermal system fit in the same footprint as their old oil furnace. They loved having extra space in the basement after removing the big oil tank. Another benefit was ditching the large, noisy air-conditioning condenser outside. Geothermal cools as well as heats and has no visible exterior features.
Geothermal heat pumps are considerably more expensive than air source types, although generous incentives reduce the gap somewhat. They are marvelous systems!
In addition to making the jump to geothermal, Tom and Lucia opted up to 100% renewable electricity through Lincoln Green Energy Choice. The combination greatly reduced the carbon footprint of their home.
What’s Next?
Since building their house, they have reduced the greenhouse gas emissions from fossil fuel use in their home by 86%. They plan to eliminate remaining fossil fuel use entirely and increase the energy efficiency of their house by:
Installing a heat pump water heater✳ to replace a propane one at the end of its life
Replacing their propane range with an induction cooktop✳
Trading in their plug-in hybrid for an all-electric car✳ when the hybrid gets old
Transitioning away from their propane grill and gas-powered lawn mower✳
Increasing the use of cellular shades for window insulation
We can all make a plan to follow in Tom and Lucia’s footsteps on the path to freedom from fossil fuels in our homes.
✳ Government-sponsored incentives reduced costs.
Tom Longnecker, Michael Moodie
This case study was developed by CFREE (Carbon Free Residential - Everything Electric), a subcommittee of the Lincoln Green Energy Committee. CFREE provides guidance on how households can reduce use of fossil fuels and decrease greenhouse gas emissions to help Massachusetts meet statewide emissions limits set for 2030, 2040, and 2050. It also provides information about state and federal incentives that help reduce the cost of such changes. For guidance on such projects at your home, contact: Lincolngreencoach@gmail.com. For more information visit: lincolngreenenergy.org.
