A few years ago, we moved into an older home that had not been renovated in over 20 years. About a year in, we needed to replace our car and address some upgrades to the house, including our aging HVAC system. In the process, we discovered that eco-friendly solutions could not only reduce our carbon footprint but also save us serious money.
Our Starting Point: The EPA's Carbon Footprint Calculator
To set a baseline for our environmental impact, we used the EPA's Carbon Footprint Calculator. We estimated our annual CO2 emissions at 79,635 lbs, as detailed below. Our primary energy source was fuel oil, and we were driving an old, gas-powered SUV about 15,000 miles per year.
LED Lighting
Our first renovation project started with light bulbs. The home we moved into had 48 can light fixtures with 65W incandescent bulbs. The bulbs were burning out with frequency, and replacements were expensive at $5 apiece.
We discovered a range of LED retrofit lighting fixtures that could be easily installed in the housing of our old recessed lights. They came with adapters that just screwed into the incandescent sockets.
The entire fixtures were just $5 apiece and came with a 7-year warranty. These units are now commonly available and provide comparable lighting capabilities to 65W incandescent bulbs at just 13W. After making the swap, we dropped our carbon footprint by 2.1%, saving $328 annually on our utility bill.
Reduced CO2 Emissions: 1,705 lbs/year, a 2.1% reduction
*Based on wattage reduction for 48 fixtures, conservatively assuming 3 hours of daily use, and the EPA's estimate for CO2 emissions from our utility provider
Utility Bill Savings: $328/year
*Based on reduced electricity at $0.12/kWh
Note that these savings do not even factor in the hardware. Incandescent bulbs are getting more expensive as they are being phased out. Our replacement bulbs were costing as much as the entire LED retrofit fixtures. Many of our incandescents were also burning out within a year, while the LED fixtures have a 7-year warranty.
An Electric Vehicle
After spending a year in the suburbs, it was clear that we needed to upgrade from our old SUV. We considered a Tesla Model Y and comparably priced SUVs that ran on traditional, internal combustion engines. We went with the Tesla, which dropped our carbon footprint by 15.3% and saved us almost $1,900 annually in fuel costs.
Reduced CO2 Emissions: 12,203 lbs/year, a 15.3% reduction
*Based on eliminating gas usage, net of additional electricity for EV charging
Fuel Savings: $1,889/year
*Based on eliminating gas fueling, net of additional electricity costs for EV charging
Savings from fuel costs were substantial, especially since we took advantage of time-of-use pricing from our utility provider. We can set the Tesla to charge in the middle of the night, when demand on the grid is lower, and the utility is willing to provide cheaper rates.
This analysis also excludes the potential savings from the hardware. When subsidies are factored in, the Tesla could potentially be more affordable than other SUVs. The performance of the Tesla is notably better than traditional SUVs that we test drove. There is good reason that the Tesla Model Y has reportedly become the best-selling vehicle on the planet.
Geothermal HVAC
Our final renovation had the biggest impact on our carbon footprint and also delivered the most financial value. Our existing HVAC was powered by a fuel oil furnace and a traditional air conditioning system. The equipment was 20-25 years old, which was nearing the end of useful life for such systems, and it showed in the performance.
We researched eco-friendly replacement options and discovered geothermal HVAC. A geothermal system taps into the earth's constant underground temperature to provide heating and cooling. The average temperature just ten feet below the surface is 55 degrees Fahrenheit.
Closed-loop geothermal systems run loops underground with a water-based solution that transfers heat from your house in the summer down to cooler temperatures below. In winter, it does the inverse, transferring heat from below ground into the house to warm it up.
This approach is far more efficient than a traditional HVAC system. During the winter, when outside temperatures plummet to single digits, a geothermal system only needs to raise the air temperature from 55 to 72 degrees. Conversely, in summer, it leverages the constant 55-degree underground temperature to effectively cool your home.
We went with a new geothermal HVAC system from Dandelion Energy, which has dropped our carbon footprint by 50%, and is saving us about $3,200 annually in energy costs.
Reduced CO2 Emissions: 39,823 lbs/year, a 50% reduction
*Estimated based on eliminating fuel oil, net of additional electricity for geothermal
Energy Savings: $2,750/year
*Estimated based on eliminating fuel oil, net of additional electrical costs for geothermal
The hardware savings from adopting geothermal HVAC were substantial in our situation. However, I am excluding them because we did benefit from excellent timing with subsidies. We were facing the replacement of our oil furnace, water heater, and two external air condensers, which we estimated would have cost $15-20,000.
The geothermal HVAC system, on the other hand, was effectively free. Government and utility subsidies covered the vast majority of the installation. We took out a small loan for the remainder, and we're saving enough each month in our HVAC energy costs to fully cover the payment. Similar subsidies are not always available, though they are likely to increase over time as governments seek to incentivize a transition to clean energy.
Total Carbon Footprint Reduction and Cash Savings
So in aggregate, we dropped our carbon footprint by two-thirds and are being rewarded with nearly $5,000 of annual savings for doing it!
Our journey to sustainability is ongoing. We are continuously seeking ways to reduce our impact. Next on our list is improving our insulation. Solar power and home batteries are not yet feasible for a home like ours, but over time we expect the technology to improve and become more accessible as well.
We've learned that clean energy solutions cannot just be great for the planet, but great for our wallets as well. We hope our story inspires others to evaluate their energy use and make changes towards a more sustainable future. After all, change begins at home.
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