Welcome to my adventure in cutting fossil fuels at home! Read the other posts in the series here:
Part 1: Reducing Heat Demand
Part 2: Converting Gas Hot Water Tank To Electric
Part 3: Converting Gas Range to Induction
Part 4: Upgrading Central AC to Heat Pump
Part 5: Summary and Discussion
My first step in achieving fossil fuel independence was to reduce heating demand by using temperature setbacks, adding attic insulation, and sealing up air leaks. The next step is to evaluate the removal of fossil fuel burning appliances.
Since my gas fired water heater had an expensive rental contract associated with it, I figured this would be a good place to go next as I could save money despite moving to a higher cost fuel. For those not living in Ontario who are wondering what a water heater tank rental is, here is a backgrounder. This article will go over some considerations when switching from gas to electric water heating and costs/savings I had doing it.
This is the whole reason I am switching from gas to electric in the first place. The bottom line is electric doesn’t burn fossil fuels, allowing me to take guilt-free showers. I generated a gas baseline from my utility bills and found my average gas usage in the summer (when the furnace is not running) was about 28 cubic meters per month. I estimated that the majority of this usage is for hot water, about 25 cubic meters. This corresponds to about 1.4 tons of CO2 emissions per year based on gas combustion and losses in mining/transportation.
By converting to electric, local CO2 emissions are zero and overall emissions are dependent on your electric grid. In Ontario, with only about 7% of electricity from fossil fuels, total emissions work out to 0.09 tons CO2. I choose to eliminate those emissions by purchasing renewable electricity through an electricity reseller. If you live in a region with a dirtier grid, emissions of electric may be closer to gas so purchasing renewable electricity could be more important. The other thing to realize is that with renewable power now cheaper in many regions than fossil fuels, your grid electricity will likely get cleaner over time. Gas will not become cleaner over time.
In general, electric tank water heaters cost less than gas. Perusing a few home improvement websites, the gas cost premium appears to be about $200 for an equivalent size tank with similar warranty. I opted to go for a mid-range electric tank that has a lifetime anti-leak warranty. This tank also has a plastic body and stainless steel element, which eliminates the need for a sacrificial anode (yay for reduced maintenance!). The purchase price was $959, plus $55 delivery and $700 installation. The lowest cost option for this size of electric tank was about $350, but I opted for the tank with more robust features.
Of course, there were additional costs associated with installation due to the change in fuel source. Before the tank was ordered, I hired an electrician to put in a 240V feed for the new tank. Estimated cost was $270 (the electrician was working on a few things). Additionally, I had to pay $105 to the rental company to close my account and remove their old tank.
So the total cost of the install was $2,312 after tax. A person with decent DIY experience and electrical safety knowledge could probably do most of the install themselves to reduce this cost. I would recommend a licensed gas fitter for removing the gas appliance.
As an aside, I also looked into hybrid electric heat pump tanks as they are the most efficient tanks available, however these run well over $2000. There would be a case for payback on electricity savings (heat pump units use about a quarter of the electricity compared to resistance), but I opted to go with the simpler option with longer warranty and fewer moving parts. Another consideration was that the heat pump units are larger and would potentially be more complex to install (may need to be vented). If lowest possible energy consumption is your goal, a hybrid electric heat pump system could be a good option for you.
Currently, gas is cheap (if you don’t price in externalities) and I was paying about $9 per month in gas to run the hot water tank. Providing the same amount of hot water with my new electric water heater costs about $24 per month. However, I was able to cancel my tank rental contract, which yielded savings of $38 per month. If you like the peace of mind of a rental contract (they will fix any issues without much hassle), they typically offer a lower rate for electric tanks because they are more reliable. Ask your rental company if you can switch to an electric tank! The lower rate could offset the electricity cost.
Overall, after the project I’m saving about $23 per month. This works out to a payback of 8 years, which in my mind is ok since I still have savings despite a higher cost fuel and have a piece of equipment that should last for decades.
The typical gas heater lasts 8-12 years, with electric lasting 12-15. There are different levels of quality and warranty for both types. As I mentioned, I purchased one with a lifetime anti-leak warranty, so I am hoping it lasts longer than that.
Gas does have one superpower that electricity has a hard time competing with and that is energy density. Gas is powerful and can heat water fast. This means if you are taking super longs showers, while running the dishwasher and laundry, gas can keep the hot water flowing longer. For example, a 40 gal gas fired tank can often make up 40 gallons per hour of hot water. The tank I chose has a 4500W element, which enables a recovery rate of 21 gallons per hour. I haven’t had any issues with running out of hot water, but if you are a high water consumer, you may consider getting a slightly larger tank if you are converting to electric. Check the recommendations on size of household for various tanks and choose one that makes sense for you.
With so much heat being blown out the vents as waste, gas cannot compete with electricity in terms of efficiency. The tank I replaced had an efficiency rating of 0.67, which means for every unit of energy input, only 0.67 actually ends up as hot water. The electric replacement tank has an efficiency rating of 0.92. Hybrid heat pump units can achieve efficiency rating of up to 4.0, meaning they can produce 4 times the amount of heat energy compared to the electric input energy.
One hot water technology I haven’t talked about is instantaneous. This type of system takes advantage of the high energy content of gas to produce hot water on demand as it is needed, avoiding tank losses. These types of systems may be harder to convert to electricity because a lot of electric power is needed to match the instantaneous energy of gas. The higher power demand may end up requiring a more substantial electric upgrade. Additionally, instantaneous systems have no tank and a much smaller footprint (often wall mounted), so it may be difficult to switch to a tank electric system due to lack of mechanical space.
Stay tuned for the next episode of Mike at Home: Cutting Fossil Fuels, which will look at the alternatives to a kitchen mainstay: the gas range. As always, feel free to get in touch to discuss your plans to kick the fossil fuel habit!