Electric Homes Run Off Sunshine

Harnessing the sun for our electricity, hot water and space heating is practical and cost effective whether remodeling or building from the ground up. After maximizing use of the sun, consider going all electric, since some or all of your electricity can be site-generated. When pursuing this strategy, it is most cost effective to reduce electrical loads (LEDs, Energy Star appliances, etc.), as fewer photovoltaic panels will be needed.

Heat pumps fit nicely into this strategy. They can heat or cool a home, provide domestic hot water, refrigerate your food and even dry your clothes. Heat pumps use electricity to move heat from one place to another instead of generating heat directly. Their high efficiency results from their capacity to transfer more energy (heat) than the energy they require to operate. They are rated by COP (coefficient of performance), the ratio of useful heating or cooling provided compared to the work required. Although they have been around for many years, recent improvements greatly increase their efficiency, achieving COPs in the 2-3 range (compared to 0.8 for efficient gas furnaces or water heaters). Variable-speed motors and scroll compressors in lieu of piston compressors are key recent advances that lower energy consumption, minimize noise and reduce maintenance. Heat pumps work best in moderate climates.

For the non-scientist, heat pumps conjure up notions of alchemy: extracting heat from already cold outside air and transferring it inside to heat the home, or when it’s hot outside, reversing direction to act like an air conditioner, removing heat from the home.

Heat pump appliances such as refrigerators, dryers or water heaters have condensers built in, while space conditioning heat pumps have two main components—an outdoor condenser and an indoor air-handling unit. In recent years, mini-split or ductless units have become popular, because of their small size and zone heating/cooling capabilities. Many models can have as many as four indoor air-handling units connected to one outdoor compressor. Each zone has its own thermostat for optimum control. It is critical that each unit be properly sized for its space to run at maximum efficiency.

Mini-splits are quick and easy to install and offer great design flexibility. They are especially practical for additions and remodels. Ductless systems offer multi-stage filtration that can drastically reduce dust, bacteria, pollen, allergens and other particulates in the air.

Heat pump equipment costs the same or slightly more than comparable natural gas equipment, but if run off sun-generated electricity, the savings add up rapidly. Even if run off utility-generated electricity, the super efficiency, along with the 30 percent federal tax credit, makes it the more economical choice. I am convinced that the all-electric home run off the sun is the future.

Electrify, Electrify, Electrify

Each Time We Replace an Appliance Is an Opportunity to Reduce Warming Emissions 

Until recently, most of us have not had choices about the power we consume: the gas for our cars or the fuel used to produce our electricity. Most supply-side choices are made by giant corporations. Fortunately, the game is shifting, at least in California and a few other states, where community choice energy programs with more clean energy, often 100 percent, are increasingly available. Santa Barbara, City and County, now have community choice programs. This is changing the supply side of the equation.

On the demand side, however, we have always had more influence: We decide what we drive, how we heat our water, what heats our house, what cooks our food, and what dries our laundry. For the past 50 years, the climate focus related to the machines and appliances we routinely buy has been on efficiency — mandated vehicle fuel standards, tighter houses through more rigorous energy codes, and Energy Star appliance performance ratings. Efficiency policies are not going to get us to zero emissions, however, certainly not fast enough to address the urgency of the climate crisis. Electrifying everything can, however, go a long way toward solving the problem — and rapidly. How fast? As fast as appliances need replacing: cars roughly every 10-20 years, home furnaces about every 20 years, and kitchen and laundry appliances every 10-15 years. 

Thankfully, we now have good choices for these replacement purchases, and they are getting better every year. Electric cars currently have good range, are close to cost parity with combustion cars, and save money every mile we drive. Air-source heat pumps for heating, cooling, and hot water now perform four or more times better than traditional appliances. The modern induction cooking experience is better than cooking with gas and is twice as efficient.

Dispersed rooftop solar can be the cheapest energy source, but we make it cost more than it needs to by cumbersome, lengthy permitting and inspection requirements. Whereas the installed cost is around $1 per watt in Australia, it ends up near $3 per watt in the U.S. When the U.S. is fully electrified, 20-30 percent of electricity can be generated locally on rooftops, and the remainder will need to come from wind farms, utility-scale solar farms, geothermal wells, and hydroelectric facilities.

Thinking about addressing climate change can be overwhelming and depressing. Replacing fossil-fuel equipment with electric units will enable us to be and feel part of the solution, without sacrificing the conveniences of modern life. Moreover, the long-term economic benefits are not only in utility bill savings, but in creating jobs. Several studies link 25 million new jobs to mass electrification in the U.S. Many of these will be local.

Once we shift to clean energy, we’ll be able to enjoy all the comforts — warmth, air-conditioning, zippy cars, and hot water — but with lower costs and cleaner air. 

Hempcrete: A Carbon-Negative Insulation

Hempcrete Moderates Indoor Humidity and Temperature, While Being Fire, Mold, and Insect Resistant

The next frontier in green building is emerging as carbon-sequestering materials. Incorporating such materials into tight, energy-efficient building shells has the potential to fully offset the 40 percent of total greenhouse-gas emissions that structures contribute to global warming. One such material is hempcrete, an innovative insulation that is better for people and the planet.

Hempcrete, or hemp lime, as it is sometimes called, is made from the woody core of the cannabis plant combined with lime and water. Hemp is fast-growing (typically 3-4 months), likes a wide range of soil and climate conditions, and requires no pesticides. An acre of hemp can sequester an impressive 10 tons of carbon dioxide, more than an acre of trees can sequester in an entire year. When turned into hempcrete, the carbon remains locked in the inner woody layer. The lime binder also sucks up carbon. However, cultivating it does require a good amount of water.

The insulating value per inch of hemp is comparable to fiberglass insulation (R-2.5-3), yet it has none of the harmful synthetic ingredients that fiberglass and most other commercial insulations contain. Hempcrete acts like a toxic-free sponge that absorbs moisture from the surrounding air when it is humid and releases it again when it is dry. This ever-adjusting behavior creates a healthier relative indoor humidity and an improved sense of comfort. It has good sound-dampening properties that also contribute to good indoor environmental quality.

The use of hempcrete is growing rapidly in Europe. It has been used in Paris since 2012 and is now being government-funded in subsidized social housing projects. It is also getting traction in the U.S. but was hindered by a later start because of the legal ban on all hemp uses, only recently lifted.

Although made from the woody core of Cannabis sativa, hempcrete is highly fire-, mold-, and insect-resistant, due to the lime envelopment of the plant elements. Not surprisingly, all the other parts of the plant can be turned into other products. The only negative for hempcrete seems to be that it costs more than fiberglass insulation, about double, although that differential will diminish as it gains market share. The product comes in various forms: batts, blown-in, blankets, and rigid boards.

Hempcrete is part of a class of composite building materials that has received negative-carbon-material classification, and among these, it is the top negative-carbon performer. Many other building materials are now being made and analyzed for their carbon-storing properties. The optimum is to create carbon-storing buildings that also operate on renewable energy, making them zero-net-energy and zero-net-carbon structures.

Greening a Bathroom

Bathrooms, along with kitchens, are the most expensive spaces to construct in a home, because of the plumbing needed, the greater density of lighting and numerous appliances. To create a sustainable bathroom, it must be energy efficient, use minimal water, be comfortable, non-toxic, quiet and basically maintenance free.

California codes keep nudging all new and remodel construction to be more sustainable. Consequently, any remodel project today triggers upgrading ALL plumbing fixtures throughout the home or business. The most recent State standards are: 1.8 gallons per flush for toilets; 1.2 gallons per minute (gpm) for bathroom faucets and 1.8 gpm for showerheads, giving California the toughest standards of any US state. For comparison, these flows are about a quarter or less of what was standard 3-4 decades ago.

Not only are these standards saving hundreds of billions of gallons of water each year, but also lots of energy and greenhouse gas emissions, since 19 percent of energy consumed in California is used to pump, transport, treat and heat or cool water.

Selecting an efficient and effective showerhead has become easier in the last decade, due to the Federal WaterSense program. To carry the WaterSense label, a showerhead must list its flow rate, which must be below the maximum allowable federal standard, and meet strict user satisfaction standards. A popular WaterSense model by Niagara, rated at 1.5 gpm and receiving stellar customer reviews, costs only about $8.

A promising development that cuts water consumption even more is the atomizer mist technology. Showerheads using this approach disperse water through millions of microscopic droplets into an effective wet area while saving 70 percent of water. Similarly, with sink faucets, the fine mist produced is a 98 percent reduction in water use, with no loss in functionality.

Controlling humidity in bathrooms is key to promoting health. Good natural ventilation (operable windows) as well as effective air-moving equipment avoids mold, mildew and rot. A good bathroom fan needs to move about 150 cubic feet of air per minute while having a noise rating of 1 sone or less, making it virtually unnoticeable.

The leading green-building thinking today emphasizes all electric homes, where the loads are minimal, and the power needed is produced on-or-off-site by the sun or wind. LED lighting and super-efficient equipment keeps loads to a minimum without sacrificing performance. Hot water can also be heated by solar electric panels or directly by solar thermal panels. Water and heat can be additionally saved by on-demand hot water delivery. At the push of a button, a pump turns on, rapidly bringing hot water to faucets while pushing the cold in-line water out into the cold-water lines rather than wasting it down the drain.

Good insulation, high performance windows, using only non-toxic materials and avoiding carpeting are additional strategies to improve sustainability in bathrooms and are even more important for the entire house. Savings on water and electricity are often easily calculable. Putting a price on good health is not easy but for most of us it is priceless.