January 15th, 2021 by Barry A.F.
One of the ways to slow the advance of climate change is to reduce your personal carbon usage. While we can’t efficiency our way to climate neutrality we can buy ourselves time by slowing the rate of carbon emissions and conservation/Negawatts are often the cheapest form of clean energy available (and the least polluting). Also when you have less energy to replace its cheaper to do so (i.e., if you cut your energy use in half, then only half the renewables are needed to make it sustainable).
Our homes can seem like a monolithic entity, they need heat and or cooling, they use water and heated hot water, they consume electricity, and need lighting and plumbing. But the structure, plus our actions, can alter how much carbon is produced by several orders of magnitude. Two equivalent homes standing side by side could have 5-20x the difference in carbon pollution produced in daily operation. A 100+ year old leaky home with inefficient appliances and high electricity use creating dozens of tons of CO2 a year can stand next to a Passivhaus or Net Zero home which has very low or even no carbon emissions whatsoever. And there is a huge continuum in between these extremes. Many existing homes that are inefficient can be upgraded to various degrees to reduce its footprint.
This will be a four part series:
Series One: Insulation And Air Sealing
Series Two: Heating/Cooling And (Hot) Water
Series Three: Plug Loads
Series Four: Building For Net Zero Or Better
The standard disclaimers apply, all advice is for informational purposes only, CleanTechnica is not responsible for any damages caused by inaccurate information or following any information provided, consult professional expertise before making any modifications to your home, all information is subject to change as our knowledge evolves, and the coffee may be hot.
This article series is focused on detached and semi-detached homes, but many of the concepts are applicable to all building types.
Most homes require heating and or cooling and hot water. These creature comforts can often be considered necessities (especially in extreme temperature locations) and we don’t think too much about them except when the appliances break down or need replacement. However when considering the carbon pollution produced, there can be huge gains to be had in all of these areas and some technologies are far more efficient than others.
Heating
Heating in modern times is typically provided by oil, propane, natural gas, wood, or electricity (in ascending order of potential carbon neutrality). There are some niche systems also available and oil heating is less common then it was in decades past though still in common use in some areas. The carbon intensity of each varies by source and volume needed. If you move towards electricity, you will be reducing your carbon output the most in the long term as the grid in most countries continues to become more renewable, and unless we destroy ourselves first will eventually become 100% renewable.
For all options the less energy you need to condition your home the less carbon/renewables you will need to satisfy it and hopefully you read the Improving The Efficiency Of Your Home, Part 1: Insulation & Air Sealing article and are able to improve your home’s efficiency as much as possible. However, if you cannot for whatever reason, increasing the efficiency of your heating appliances will still typically save you some money and reduce the amount of carbon produced. If you combine building efficiency upgrades with the most efficient appliances available, you can maximize your efficiency and savings.
The debate between radiators and forced air has passionate defenders on both sides, but if your goal is to reduce carbon then amount of fuel used for comfort is what matters.
Heating Oil is the most carbon intensive heat source available, it often has to delivered by diesel-powered truck, it is very polluting when burned, and the efficiency from many older units is atrocious. For very old units, determining the efficiency will be very difficult, but an experienced energy auditor may be able to provide some direction or have experience with your particular unit. If you are very lucky, the manufacturer may still be in business and may have some data to provide if you ask nicely. Newer units are more efficient, but not preferable to electricity by any stretch of the imagination. The best way to cut your carbon here is to switch away from oil-based heating. Biofuels are not a solution, they are a distraction and cannot scale anyways even if they were the way to go.
Propane is often used for heating and cooking and refrigeration in places where the grid does not reach. It’s often delivered and replenished as needed. It is far less polluting than oil and the efficiency of the appliances varies a fair bit. If you’re off grid, completely replacing propane with electricity in a retrofit situation can get tricky because propane can be stored for months or years while 100% electricity would mean lots of solar panels and storage, hoping you do not run out faster than you can generate more electricity on site from the sun or wind. However, it is worth checking on the efficiency of propane furnaces/appliances and doing the math as to whether upgrading is cost effective (or at the end of life buying the highest efficiency replacement unit). You may also consider a ducted or ductless heat pump combined with solar (and maybe battery) and keep the propane for backup, which could cut your carbon a great deal and greatly reduce the frequency of propane replenishment, since a renewable setup — if sized properly — can handle a decent or even high percentage of the load, in fact further increasing your resilience to supply disruptions.
Cooking and refrigeration can typically be replaced by electricity and are often far less energy consuming, reducing the risk of running out of propane by a huge percentage. Induction cooking is rather miserly on power and electrically powered refrigerators can be very efficient if you buy carefully and go with only the size you need, smaller using less energy (typically). Do the math before deciding on any changes to your current setup, with the help of an efficiency professional if necessary.
Stay tuned until next week for Part Two.
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About the Author
Barry A.F. I’ve had an interest in renewable energy and EVs since the days of deep cycle lead acid conversions and repurposed drive motors (and $10/watt solar panels). How things have changed.
Also I have an interest in systems thinking (or first principles as some call it), digging into how things work from the ground up.
Did you know that 97% of all Wikipedia articles link to Philosophy? A very small percentage link to Pragmatism.