This past weekend 350 Colorado hosted a Renewable Energy Summit with a focus on ‘Moving Beyond Fracked Gas.’ Led by 350 Colorado’s new Renewable Energy Committee, the summit offered an opportunity to learn about renewable energy solutions and how to support the just transition to 100% renewable energy in Colorado. The below guest post was compiled by Ron Bennett, an architect and member of the 350 Colorado Renewable Energy Committee. Ron is available to support members of the 350 Colorado community who would like to fossil-free their homes. Please contact him to learn more!
State of the Art Technology for a Fossil-free Home – a guest blog post by Ron Bennett
Homeowners are faced with a multitude of options for making their homes more efficient and ultimately, carbon neutral. This document will outline systems and products that can reduce or eliminate reliance on fossil fuels for residential space conditioning and domestic needs.
Efficiency is an important first step on the path to a zero-carbon future. Reducing energy consumption in the home pays dividends in energy savings while reducing peak equipment loads.
These improvements will reduce a home’s energy footprint:
- Replace incandescent lamps with LED lighting
- Replace an old refrigerator with an Energy Star certified unit on the agency’s Most Efficient list
- Install well insulated and weather-stripped exterior doors, windows and skylights
- Thermal insulation upgrades to the building envelope
- Proper air sealing of the building envelope
- Regular maintenance and filter changes keep systems running at peak efficiency
A well-insulated and sealed home can be kept comfortable with a lower capacity, less costly ventilation system. But as homes become tighter, providing adequate fresh air is crucial. Homes built to the PassivHaus standard — one of the most stringent — utilize a heat-recovery ventilator (HRV), which captures thermal energy from exhaust air to condition a continuous source of fresh air.
Heat pumps represent the state of the art in electrically powered thermal control. They utilize a compressor and refrigerant loop to absorb heat from air or water in one place and release it in another. Precision engineering, controls, and manufacturing have improved performance and efficiency of today’s heat pumps while lowering operating temperature range down to near 0°F. These versatile devices can heat and cool your home while also offering the most efficient way to make domestic hot water using electricity. This equipment offers a means to eliminate your home’s reliance on fracked gas:
- While a heat pump water heater (HPWH) may cost about $900 more than a conventional electric water heater, it can potentially save $300/year for a family of four; only a 2-year payback after $400 rebate. Larger tank sizes, up to 80 gallons, are appropriate for large families. Cool air is a by-product of a HPWH, which can be beneficial for humidity control or cooling, but will require some breathing room (min. 700 cubic feet) or ducted equivalent.
- Heat pump clothes dryers are ventless and efficient, suitable for apartments, retrofits, or to replace a gas dryer. But in this case, the state-of-the-art is still an old-fashioned clothesline!
- An air-to-air heat pump can replace an existing gas furnace, offering both heating and cooling with an integrated system. Higher HSPF and SEER ratings indicate better performance with lower operating costs (albeit at a greater upfront cost).
- Mini-splits offer an affordable way to retrofit homes without existing ductwork. Indoor units are simply wall mounted (surface) or built in (cassette or slim-duct). Look for SEER ratings up to 30 and “low ambient heating” capability for colder climates.
- Ground-source heat pumps (GSHP) transfer thermal energy underground via a buried, closed water loop. Because subsurface soil temperatures remain around 50°F year-round, this makes an attractive heat sink while eliminating noisy outdoor units. Geothermal offers superior performance but with greater complexity and initial cost. GSHP remains an attractive option as geo qualifies for a 26% renewable energy tax credit.
While heat pump technology continues to improve performance while lowering costs, the market ultimately drives product development and availability.
Heat pumps with invertor-driven compressors can vary output capacity to match demand and even move energy within a building, balancing demand with less energy. Yet this technology hasn’t trickled down from the commercial market to residential applications.
Systems utilizing air-to-water heat pumps integrate space conditioning with domestic hot water production, simultaneously heating water while cooling space. These systems have the controls and flexibility to integrate with radiant heating and/or a thermal solar array. Sadly, air-to-water heat pumps for residential applications are sold in Asia, Australia, and Europe but not on this continent. Manufacturers cite a lack of customer demand, which likely can be attributed to the availability of cheap natural gas.
The price of natural gas doesn’t represent its true cost of extraction, distribution, and associated environmental impacts. This makes electrically powered, high-efficiency appliances and systems less attractive to builders and consumers focused only on cost, lowering demand, and in turn stifling innovation.
That said, there’s one product intended to replace a very common gas-fired appliance that many find superior to its fossil-fuel burning counterpart: Induction cooktops utilize an electromagnetic field to directly heat “induction-compatible” cookware. They heat up very quickly and changes to heat settings are nearly instantaneous. A simple glass top is easy to clean and conveys a slick, modern aesthetic. The cost of this tech has been dropping, and its superior performance should outweigh the premium price.
The question remains: how will you feed all of this electrically powered, new technology? If you buy power from Xcel Energy, know that three quarters of it is still derived from fossil fuel sources. This is not your greenest option. A company that commits to do the right thing by 2050 is twenty years too late to the game. As an Xcel customer however, you can pressure Xcel to do more and sooner. Better still, be your own clean energy generator and earn a 26% tax credit in 2020. Distributed generation with storage is the future of a resilient zero-carbon energy grid. A rooftop or ground-mounted solar array will put you on the road to energy independence:
- Thermal panels — the OG panel tech — circulates water through panels, directly heating floors or making domestic hot water via a heat exchanger. As the costs of PV panels continue to decline so has the application of thermal panels. Probably best suited to homes with limited area for panels, an array with as few as three panels and good sun exposure should satisfy hot water requirements for a family of four.
- Photovoltaic (PV) panels are available in abundance and prices have never been lower. Consider roof condition, orientation, and any tree cover when initially evaluating your property’s solar potential. Enter your home address at www.google.com/get/sunroof to learn more. Be sure to sign up for Boulder County’s free EnergySmart program at www.energysmartyes.com for expert help in evaluating the feasibility and cost of efficiency upgrades, a PV solar array and storage options, all with low-cost financing available.
- Support sustainability in your community by subscribing to a solar garden if tree cover or other constraints prevent the installation of a solar array on your property.
I hope you find this overview helpful in your quest to go fossil-free. If you have any questions or would like to explore specific zero-carbon solutions for your home or business, please let me know. I’m always glad to discuss this subject with any member of 350 Colorado.
Ron Bennett is an architect who’s spent almost four decades in the building business. Inspired by recent youth movements and the resolve of groups like 350.org and 350 Colorado he’s now focused on contributing what he can toward climate justice and a zero-carbon future.
*Questions? Ron welcomes questions and is happy to support members of the 350 CO community. You can contact Ron via email at firstname.lastname@example.org