Natural Gas, or methane, has been promoted both nationally and locally as a ‘Clean Fuel’ and ‘Bridge Fuel’ in various circles during this time of climate crisis.
Concurrently, the Intergovernmental Panel on Climate Change (IPCC) has called for a fast decline in the use of fossil fuels, more rapid scaling up of renewable energy, and avoiding a lock-in of high-carbon infrastructure.
Green House Gas Emissions and the Role of Natural Gas
In the U.S., buildings generate nearly 40% of annual global greenhouse gas emissions. In order to meet climate goals as set by the IPCC, the U.S. needs to move beyond the burning of fossil fuels, including the use of natural gas. Burning methane is now a bigger source of climate-altering emissions than burning coal, and nearly a third of that gas is burned in homes and commercial buildings.
Passive House buildings present an especially easy opportunity to cut the gas line and go all-electric, due in part to their extremely low heating and cooling demands. This, coupled with the cost savings of not having to install a gas line, makes Passive House buildings great candidates for a simple transition to an all-electric building. All-electric buildings are the easiest path towards a net zero-carbon built environment, when electric usage is offset with renewables.
In Support of All-Electric Buildings
It turns out that ‘cutting the gas line’ can be a win-win scenario in a Passive House building. There is a myriad of negative aspects of burning gas that can be avoided by switching to all-electric buildings. Issues such as methane leaks, groundwater pollution from fracking, pipelines through native lands, forests, rivers and ecologically sensitive areas, earthquake risks, explosions, increased fire risk, dangerous indoor air quality, bad public policy and negative health risks can all be avoided.
By avoiding natural gas and pairing all-electric energy with Passive House, we have buildings with even better energy efficiency, lower energy bills, higher indoor air quality, less risk of fire, higher comfort and better performance. We should advocate for buildings that are longer-lasting and more resilient and responsive than those that rely upon fossil fuels.
All-Electric Design Considerations
Of course, designing and building an all-electric building can have its challenges: economic, architectural and behavioral. These issues can be mitigated with smart systems choices, energy efficiency savings, and educating one’s self or one’s clients ahead of time about the slightly different ways of living in an all-electric building.
This dovetails perfectly with Passive House best-practices, as most practitioners are already addressing a number of these issues with their projects and educating their clients about life in a Passive House.
From an economic standpoint, heat pumps for heating/cooling and water heating, LED lighting, and induction ranges can potentially add a premium to the already constrained budget. This should be tempered with the cost savings of the improved energy efficiency of these systems over time. Heat pumps can be up to 250% more efficient (and up to 500% more efficient in some water heating applications) relative to the combustion of natural gas, thus saving money and impacting cash flow positively from day one.
This savings reduction can be especially impactful if the building is intended to be a rental, because the increased costs of all-electric HVAC systems can be offset by charging “typical” utility rates to the tenant. The tenant, even if paying typical utility fees, will be able to take advantage of the higher indoor air quality, better comfort, and other benefits of going all-electric, so there is a qualitative positive value for the tenant.
“Additionally, it typically costs between $1,500 and $2,000 to install a gas line to the building. These initial savings can be put towards these systems and can temper the upfront costs of upgrading to all-electric.
“But, I Like Cooking on a Gas Range”
The main behavioral change of going all-electric is letting go of the gas cooktop. This is likely the biggest hurdle to removing gas from a building (at least in the residential vernacular—commercial buildings can have a different set of constraints).
As opposed to the old electric resistance cooktops that took forever to warm up then turned uncontrollably red hot, induction ranges perform as responsively as gas cooktops, and address a number of typical concerns:
Induction ranges use magnetic induction to heat the pan itself and are extremely responsive and precise when adjusting temperatures.
Since they don’t heat up the surface of the cooktop, they reduce the potential for burns and are safer than electric or gas cooktops.
They are powerful, being able to boil a pot of water in an astonishingly short time, while also sensitive enough to sauté delicate sauces without overheating or burning.
Granted, charring the peppers or some wok cooking may be out of the question, but a few minor behavioral changes or using an outdoor grill are generally acceptable.
Indoor Air Quality
Another issue with gas cooking is the associated indoor air quality issues that arise through combustion during cooking. Gases such as nitrous dioxide, carbon monoxide, formaldehyde, mercury, methane and particulates are produced when burning natural gas.
These gases and particulates have been associated with negative health effects such as respiratory disease, chronic respiratory illness in children, decreased pulmonary function, depression, cancer, nervous system disorders, birth defects and organ damage, among others.
An induction range does not combust anything, therefore bypasses a lot of these issues. As always, it is a good idea to have a vent hood with a large capture efficiency that includes make up air and is vented directly to the outside to capture any cooking particulates.
All-Electric Water Heating
Switching to an electric heat pump hot water heater can present challenges. Heat pump water heaters can dump cold air into the surrounding conditioned space. This should be avoided (or at least cleverly managed), if possible. One solution is to order a venting kit that brings in make-up air and vents to the outside, thus avoiding some of these issues.
In order to do so, the unit should be located near an exterior wall, though this then has the potential to complicate design.
There are newer split hot water heaters such as the Sanden System, which locate the condenser on the exterior of a building, similar to a HVAC heat pump. They are extremely efficient, topping out at a whopping 500% efficiency.
These work really well for flexible building design, as they can be located farther from an exterior wall and the smaller units are only 4’ tall. Smaller Sandens behave like a much larger unit since they hold the water at a higher temperature, so there is little worry of ever running out of hot water. The downside is the higher cost, but they pay for themselves over time and do allow for a much less constrained design.
Going all-in on the all-electric building shouldn’t be too much of a stretch on the West Coast. There are numerous companies that have been producing all-electric Passive House buildings for years now without complications or complaints from the people that live in them. Additionally, there are a number of jurisdictions across the country that have implemented a ban on natural gas in new construction or are otherwise considering doing so. Cities such as Berkeley, CA have passed bans and others in northern California have followed suit. Recently Santa Monica and cities in Massachusetts, Oregon and Washington have started contemplating changes to their codes.
All-Electric Homes are Like Chocolate Falling in Your Peanut Butter
To continue building with natural gas as one of our main sources of fuel is locking ourselves into decades of carbon emitting infrastructure, stranding assets, and reducing flexibility in future climate response options.
There are mostly upsides to getting rid of natural gas in our buildings. The natural gas industry would like to make you think otherwise, by promoting concepts like ‘Balanced Energy Solutions’. However, the goal of this post is to get you to take an objective look and consider the rewards of switching to an all-electric and Passive House building. You could say that the combo is as natural as chocolate and peanut butter.
(Featured image courtesy of jules.)
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