What are the most effective options to replace my house's carbon use?
August 25, 2020 1:00 PM Subscribe
I recently became a first time homeowner in the seattle area and I'm considering adding some improvements to offset as much of our energy consumption as possible, but I'm a little overwhelmed by the options. I've done a little research on what options are available, but I'm having a hard time identifying the most effective option. Given the specifics of my home, what changes should I consider first?
A quick note, this question isn't about how I can change the carbon footprint of my behavior, I'm specifically asking about what I can add to my home to reduce its carbon reliance.
Here are the specifics of our situation and the options I'm aware of so far.
What options are most cost effective in terms of dollars to carbon offset?
A quick note, this question isn't about how I can change the carbon footprint of my behavior, I'm specifically asking about what I can add to my home to reduce its carbon reliance.
Here are the specifics of our situation and the options I'm aware of so far.
- Solar & battery: Due to a 3 story neighbor, a Douglas Fir, and the anemic Seattle sun, this may not be a great option for us. Google's sunroof tool says the maximum panel we could do would fall short of matching our energy use and only pay for itself after 20 years. Also, Seattle power is something like 98% renewable/nuclear so electricity seems like less of a concern here. Am I missing anything here that would make this viable?
- solar thermal: Despite those challenges, maybe some solar heating is viable still? Solar water heaters seem cheap, but are they actually practical? Beyond heating water are there other options here I'm unaware of?
- Heating: The main floor of our house is heated by a gas furnace. The lower and upper floors are also heated by separate electric forced air panels. Presumably, given how green our electricity is, just replacing the gas furnace with something electric would be a big gain, right?
- A heat pump: I'm not super familiar with these, but presumably this would be more effective than going all in on electric heating right? We have a decent sized backyard to put it under.
- Other gas appliances: Just a stove and a water heater. Eliminating these should be a small but simple gain if my assumptions are correct.
- Electric car: This is sort of out of scope of the question, but if replacing our single car required for my wife's commute would have a bigger impact than any of the above we should consider it. The challenge is that we have no driveway to charge it in. How practical is an EV while depending on charging stations these days?
What options are most cost effective in terms of dollars to carbon offset?
- What options are most cost effective in terms of installation cost to utility bill reductions?
- What options most reduce our dependence on external utility companies?
- Are there any other options I'm not aware of?
Is your house already well-insulated and sealed? That can make a huge difference in your energy consumption. Can you get an energy audit? (Ours was free to us, and officially wasn’t supposed to include any recommendations involving changes from electric to gas or vice versa but our guy did clue us into the existence of hybrid hot water heaters, which I hadn’t known about before, and it made us eligible for very low cost insulation and weatherization.)
Also a heat pump is just a backwards air conditioner - I think you’re maybe asking specifically about a geothermal heat pump?
posted by mskyle at 1:20 PM on August 25, 2020 [1 favorite]
Also a heat pump is just a backwards air conditioner - I think you’re maybe asking specifically about a geothermal heat pump?
posted by mskyle at 1:20 PM on August 25, 2020 [1 favorite]
Use an online carbon footprint calculator to estimate this, but depending on how much you drive the car and what kind of car it is, replacing the car might have the biggest impact. But getting an induction stove should be low-hanging fruit, and then a ground heat pump.
posted by pinochiette at 1:22 PM on August 25, 2020
posted by pinochiette at 1:22 PM on August 25, 2020
One more tip: Insulate and Weatherize: For Energy Efficiency at Home is the single book I see recommended most often. The title is misleading: it covers most of your question, not just insulation.
posted by caek at 1:26 PM on August 25, 2020 [1 favorite]
posted by caek at 1:26 PM on August 25, 2020 [1 favorite]
Excellent winter house slippers for everyone can drop the tolerable low thermostat setting by a few degrees. Think how that adds up over decades.
And insulate the house, too, and remember that a tube of caulk and some paint every summer can forestall high emergy repairs for decades. Maintenance and operations before construction, unless the construction you have is really terrible.
posted by clew at 1:42 PM on August 25, 2020
And insulate the house, too, and remember that a tube of caulk and some paint every summer can forestall high emergy repairs for decades. Maintenance and operations before construction, unless the construction you have is really terrible.
posted by clew at 1:42 PM on August 25, 2020
I think the suggestion to try to improve the insulation of your house could be really effective. We moved last year into a fixer upper and explored geothermal for the HVAC. The contractor we had give us an estimate was part of a company that was one of the first in the state to adopt those technologies and he said that it just wouldn't be cost effective for us - you either need a really big backyard to run a horizontal system or be prepared to dig down pretty deep. He ballparked a cost in the tens of thousands.
What we ended up doing was having electric heat installed, and, because our house is two stories in a warm climate (NC), we had two AC units installed, one for each floor, with separate thermostats. NC does pretty well in solar energy, and hopefully we will bring more offshore wind energy online eventually, too, so that our all-electric HVAC can be completely renewable.
I think an electric car could work. We bought a used 2015 Nissan Leaf a few years back and love it. We just plug it in to a standard wall outlet and let it charge overnight. We never have a problem with it, but I think a climate like Seattle would be even more ideal than our hot, humid summers (when you have to run AC in the car).
You mention that you don't have a driveway, so I presume you park your car in front of your house. Maybe an electrician could give an estimate on running some sort of line to the front of your lot and then providing an unobtrusive, secure outlet. You could keep the charging cable in the car and then plug it in, maybe with a locking cover over the outlet..? I guess it could be a tripping hazard if it then has to cross a sidewalk. Still, I would investigate something like that.
Good luck!
posted by Slothrop at 1:52 PM on August 25, 2020
What we ended up doing was having electric heat installed, and, because our house is two stories in a warm climate (NC), we had two AC units installed, one for each floor, with separate thermostats. NC does pretty well in solar energy, and hopefully we will bring more offshore wind energy online eventually, too, so that our all-electric HVAC can be completely renewable.
I think an electric car could work. We bought a used 2015 Nissan Leaf a few years back and love it. We just plug it in to a standard wall outlet and let it charge overnight. We never have a problem with it, but I think a climate like Seattle would be even more ideal than our hot, humid summers (when you have to run AC in the car).
You mention that you don't have a driveway, so I presume you park your car in front of your house. Maybe an electrician could give an estimate on running some sort of line to the front of your lot and then providing an unobtrusive, secure outlet. You could keep the charging cable in the car and then plug it in, maybe with a locking cover over the outlet..? I guess it could be a tripping hazard if it then has to cross a sidewalk. Still, I would investigate something like that.
Good luck!
posted by Slothrop at 1:52 PM on August 25, 2020
Nthing the advice to look at air sealing first, insulation second. With that out of the way, to address your other points:
* Given that your property is a poor candidate for PV, I would be a bit skeptical about solar hot water as well. Specifically, if your electric power mix is already highly renewable, you are likely better off just converting to an electric source for domestic hot water, likely a heat pump for best efficiency.
* A heat pump is going to be more efficient than electric resistance heat by a long shot. If you can fully remove carbon fuel consumption from your home by replacing your furnace with a heat pump this is an environmentally meaningful big step.
* Replacing your stove is pretty straightforward and induction ranges have a lot going for them.
* Assessing the car versus home question would require comparing current levels of consumption on both. Given what you have stated about logistics, I think it makes more sense to focus on the house. A car is a shorter term investment and the performance and efficiencies in all electrics are still growing by leaps and bounds with time. Any home upgrades are likely to have a long life return (and would even positively influence a later occupant should you decide to move).
posted by meinvt at 1:57 PM on August 25, 2020
* Given that your property is a poor candidate for PV, I would be a bit skeptical about solar hot water as well. Specifically, if your electric power mix is already highly renewable, you are likely better off just converting to an electric source for domestic hot water, likely a heat pump for best efficiency.
* A heat pump is going to be more efficient than electric resistance heat by a long shot. If you can fully remove carbon fuel consumption from your home by replacing your furnace with a heat pump this is an environmentally meaningful big step.
* Replacing your stove is pretty straightforward and induction ranges have a lot going for them.
* Assessing the car versus home question would require comparing current levels of consumption on both. Given what you have stated about logistics, I think it makes more sense to focus on the house. A car is a shorter term investment and the performance and efficiencies in all electrics are still growing by leaps and bounds with time. Any home upgrades are likely to have a long life return (and would even positively influence a later occupant should you decide to move).
posted by meinvt at 1:57 PM on August 25, 2020
I think in climate like Seattle, after insulation and sealing, adding thermal mass would also be good. This can be in terms of things like stone countertops and tables and tile flooring where available. Also adding overhangs over windows and exterior shutters for the summer time are also good options.
posted by The_Vegetables at 2:20 PM on August 25, 2020
posted by The_Vegetables at 2:20 PM on August 25, 2020
I'd give it some time. Collect some usage data. I'm in the same area, with a smallish, oldish house that's probably leaky as heck and doesn't have a particularly efficient furnace. And after going through and switching to LED bulbs, there was pretty much nothing left that was plausibly cost effective. The weather is, for the most part, too mild for there to be a lot of big wins sitting on the table.
posted by wotsac at 2:58 PM on August 25, 2020 [3 favorites]
posted by wotsac at 2:58 PM on August 25, 2020 [3 favorites]
(Like in our case, we might spend a PEAK $25/mo in Jan and Feb on natural gas over our water heater and keeping the gas turned on base price. You can't turn, say, $160/yr on heat into a return on investment.)
posted by wotsac at 4:08 PM on August 25, 2020 [1 favorite]
posted by wotsac at 4:08 PM on August 25, 2020 [1 favorite]
Jumping in to +1 to wotsac's comments. I assume if you are asking this question and recently purchased in Seattle that you are more financially comfortable than the average bear, but changing everything to electric, while environmentally better, will probably cost you more in ongoing energy bills. I'm not saying not to do it, but home ownership is expensive and you'll want a good handle on your household's energy use and costs before you embark on expensive projects.
That said -- there may be some easy low-hanging fruit by changing out some appliances. For example, we had an "energy star" electric water heater that wasn't that old, and switching it out has saved us ~$50/month on our electric bill, no lie. Updating other appliances over time has reduced electric use, though not quite that dramatically.
BTW - the "free" energy assessment from Seattle City Light or PSE are fine, but I don't think it will give you the level of detail you want. Basically they are reps from private companies who will just tell you if you qualify for certain subsidies. It sounds like you really care and want to get the most environmental bang for your buck -- hire your own independent consultant if it's feasible.
posted by stowaway at 4:31 PM on August 25, 2020 [1 favorite]
That said -- there may be some easy low-hanging fruit by changing out some appliances. For example, we had an "energy star" electric water heater that wasn't that old, and switching it out has saved us ~$50/month on our electric bill, no lie. Updating other appliances over time has reduced electric use, though not quite that dramatically.
BTW - the "free" energy assessment from Seattle City Light or PSE are fine, but I don't think it will give you the level of detail you want. Basically they are reps from private companies who will just tell you if you qualify for certain subsidies. It sounds like you really care and want to get the most environmental bang for your buck -- hire your own independent consultant if it's feasible.
posted by stowaway at 4:31 PM on August 25, 2020 [1 favorite]
(Like in our case, we might spend a PEAK $25/mo in Jan and Feb on natural gas over our water heater and keeping the gas turned on base price. You can't turn, say, $160/yr on heat into a return on investment.)Sure, gas is cheap, which means a more efficient gas appliance (oven, water heater, furnace, etc.) isn't going to save a lot of money in the long run. Full electrification of that system may even cost money in the long run.
But the question isn't about saving money! It's about using (presumably finite) resources of time and money to reduce carbon output. If you use gas to heat your home, water and food, it's probably 5-10% of your carbon footprint. If you don't fly much and your electricity is renewable and you live in a city, it might even be the single biggest contributor to your footprint.
Simply saying "I'll ignore this part of my home because doesn't personally cost me a lot of money" is not a good way to figure out how to do what the OP wants to do.
posted by caek at 4:47 PM on August 25, 2020
I'm working on this same problem, and in the same geography.
If you're serviced by PSE, the Green power option isn't bad. It bumps costs by about 10% while reducing carbon to near zero levels. If you live in one of the non-PSE areas, you can see if you have Community Solar as an option from your provider in addition to other green power options.
Your idea of changing your water heater and furnace to electric are great ones in combination with buying renewable electric. That said, new units require carbon to manufacture so you may need to do research to determine if it's more environmentally sensitive to use them through a portion of their life _then_ switch, or to switch immediately. I decided to proactively replace an extremely energy-thirsty furnace, but intend to keep using a fairly efficient gas-fired tankless water heater until it's lived a good life.
PSE sells carbon offsets, essentially increasing the size of a forest, to try to offset natural gas a bit. But you can't beat just _not_ using the gas in the first place.
Another action you could consider would be to establish a garden. This would help shift your food consumption toward vegetables (and would eliminate transportation to get those veggies). Even an indoor garden that requires power (e.g. click and grow, or aerogarden) should be good if you're buying green power.
As for cars, hybrids and electrics both move the needle in a big way.
posted by whisk(e)y neat at 5:08 PM on August 25, 2020
If you're serviced by PSE, the Green power option isn't bad. It bumps costs by about 10% while reducing carbon to near zero levels. If you live in one of the non-PSE areas, you can see if you have Community Solar as an option from your provider in addition to other green power options.
Your idea of changing your water heater and furnace to electric are great ones in combination with buying renewable electric. That said, new units require carbon to manufacture so you may need to do research to determine if it's more environmentally sensitive to use them through a portion of their life _then_ switch, or to switch immediately. I decided to proactively replace an extremely energy-thirsty furnace, but intend to keep using a fairly efficient gas-fired tankless water heater until it's lived a good life.
PSE sells carbon offsets, essentially increasing the size of a forest, to try to offset natural gas a bit. But you can't beat just _not_ using the gas in the first place.
Another action you could consider would be to establish a garden. This would help shift your food consumption toward vegetables (and would eliminate transportation to get those veggies). Even an indoor garden that requires power (e.g. click and grow, or aerogarden) should be good if you're buying green power.
As for cars, hybrids and electrics both move the needle in a big way.
posted by whisk(e)y neat at 5:08 PM on August 25, 2020
I'm not sure that replacing working gas appliances is a great move consumption wise. Don't forget the concept of embodied energy-e.g. making a new electric appliance from scratch, shipping it from China or wherever and getting it to a retailer has a huge carbon footprint. It MIGHT make environmental sense to swap out a furnace, but the energy consumed by a gas stove is negligible. I'd think about swapping things out as they break rather than scrapping perfectly good stuff, unless a particular appliance has been identified as an energy hog.
posted by Larry David Syndrome at 5:44 PM on August 25, 2020 [2 favorites]
posted by Larry David Syndrome at 5:44 PM on August 25, 2020 [2 favorites]
Electrification (replacing your furnace and stove) is a good item to keep on your list. Helps with indoor air quality, too.
posted by slidell at 8:35 PM on August 25, 2020
posted by slidell at 8:35 PM on August 25, 2020
Since over 90% electricity produced by of Seattle Utilities comes from hydroelectricity it's already pretty clean.
But since over 2/3 of Seattle's buildable land is zoned for single family homes, you could help reduce the need for long commutes and the carbon emissions created by them by advocating for better land use policies overall.
And since over 40% of the county's emissions come from transportation, supporting public transit, getting an e-bike, and walking more will also go a long way to reducing your carbon footprint.
posted by brookeb at 10:11 PM on August 25, 2020 [1 favorite]
But since over 2/3 of Seattle's buildable land is zoned for single family homes, you could help reduce the need for long commutes and the carbon emissions created by them by advocating for better land use policies overall.
And since over 40% of the county's emissions come from transportation, supporting public transit, getting an e-bike, and walking more will also go a long way to reducing your carbon footprint.
posted by brookeb at 10:11 PM on August 25, 2020 [1 favorite]
Does your energy utility offer a wind power option? I opted into Xcel Energy’s Windsource program for 100% of my electrical bill. I pay a monthly surcharge calculated on usage - last month it added about $4 to my bill. It seemed easier and cheaper than investing in solar panels and waiting years for them to pay off. I drive an electric car, and it feels pretty cool to know that it is wind powered!
Unfortunately there’s no similar option for my gas bill, which is sad because I have a gas furnace and live in Minnesota.
posted by Maarika at 12:37 PM on August 26, 2020
Unfortunately there’s no similar option for my gas bill, which is sad because I have a gas furnace and live in Minnesota.
posted by Maarika at 12:37 PM on August 26, 2020
This thread is closed to new comments.
The lowest hanging fruit is usually to pay your utility company extra for green power which is apparently not an issue/option for you, but after that, the details of house, geography and lifestyle matter a lot, so the next step should probably to get an independent house energy audit. This is likely to run you a few hundred to the low thousands, but if you're serious about identifying the most impactful things you can do (rather than doing random things that seem like they should help, or that the person advising you has a financial interest in you doing) then it's the place to start before spending money or making big changes.
posted by caek at 1:12 PM on August 25, 2020 [2 favorites]