Lets compare three common green projects people consider. Heat-pump installation, switching the gas guzzler to an electric vehicle (EV), and putting solar on the roof. We use Canadian green-house emissions statistics, and my experience with the first two (plus some planning/googling for the third), to see how the economics and user experience compare. As is often the case with infrastructure, it needs to be replaced after a certain in-service life. Thus if you need a new furnace, a new car or a new roof. that’s the cheapest time to go green.
Methodology: We look at the extensive database compiled by the government of Canada (source), to compare Canada-wide what percentage of green house gas emissions can be eliminated by our three technologies (Heat-pump, EV and Solar). Next we look at the total project cost, and any incentives that might help the budget. Here we rely on my previous posts on the subject, or in the case of solar, googling. We also list any cost savings that might be had with these projects. For fun, we add a few no, or low-cost options that if done might substantially reduce your carbon footprint. With that, lets look at the table.
| Category | Heat-pump | EV | Rooftop solar | Home battery | Going vegan | Two wheels |
| Canada-wide GHC emissions (percent of total) | 5 % | 11 % | 8 % | 8 % | 7.5 % | 11 % |
| Project cost | 15k CAD | 14-35 k CAD | 15 k CAD | 15 k CAD | 0 | $1000 CAD |
| Project “extra-cost” compared to conventional solutions | $500 CAD | ~ 10 k CAD | 12 k CAD | 15 k CAD | 0 | Lot cheaper than a car |
| Possible savings on a yearly basis | potential $100 but likely to pay more | 2990 CAD | ~ 600 CAD | 1000 CAD | ~ 2600 CAD for a family of 4 | ~ 16k CAD |
Green efficiency | 300 % | 90 % (source) | 20 % (source) | 90 % (source) | 25 % (source) | 25 % (source) |
| Traditional efficiency | 95 % | 20 % (source) | N/A | N/A | 4 % (source) | 20 % (source) |
| Green efficiency improvement | 3 x | 4.5 x | N/A | N/A | 6 x | 1.25 x |
| Payback period, full cost | Probably going to cost more, but perhaps 30 years | 5-15 years | 30 years | 15 years | Right away | 1-2 months |
| Payback period, “extra-cost” | 5 years | 3 years | 25 years | 15 years | Right away | Right away |
| Lifestyle notes | Almost invisible, it just sits there and heats my house, do change the furnace filter more often | If home charging is available, its very convenient, better than the gas car I say. Long road-trips may require planning around charging. | Seems almost invisble (source) although some maintenance/cleaning might be required | When set up, it just sits there, charges up on the cheap ULO rate, feeds back during the day | I do like my burgers (source), but the vegan ones are getting pretty good | Wintertime cycling is a character building experience. Works great for shorter commutes and local trips. |
I find it curious how even the “green-house-gas” row is. All of our projects range from 5-11 % in terms of their potential climate impact. Heat-pump, EV (or two wheeler), plus solar gets you about 24% reduction in green-house-gas emissions. Not bad, combined with the 10 % green-house-gas reduction that already happened before 2020, just about all we need to hit our Paris agreement targets (source). I may not have to go vegan (although the economics and sizable green-house gas reduction are tempting).
The “extra-cost over conventional solutions” row is whats going to determine the best way forward for you. If you need a car, you will be spending a fair bit of money no matter what you do. Why not spend a little more and get the greener and yes in the long run, less expensive alternative. Same with heat-pumps, here in Toronto, I consider air conditioners to be essential kit. Swapping out the heat-pump for the AC, is a relatively small premium. Even for solar, there are similar opportunities. Combine solar with your next roofing job. My home insurer insists that I redo the roof every 15 years. That means, I can combine the roofing job with the solar job, for more savings.
This perhaps, is what will decide the best order for you? Is your furnace/hot water heater getting old? Then perhaps start with the heat-pump. How about the car, is it getting to its end of life? Perhaps time to go EV shopping? Roof getting old? Do consider solar…
Another approach is to focus on efficiency. Looking at our table above, seems the best deal there is to go vegan. While there is some debate between agricultural experts, a 6-1 ratio is a common number, namely that it will take 6 pounds of feed to produce one pound of beef. Perhaps that soy burger is not such a bad deal?
The gas car takes second place on our efficiency metric. Namely, only about 20 % of the energy in gasoline winds up moving the wheels, compared to 90 % of the electricity the charger provides. Thus our EV here has 4.5 fold efficiency improvement. Time for an EV?
Electric car adventures 