As painfully underscored in my own personal experiences, it is not easy to zero-out one's energy-related carbon footprint from home and cars. That said, you don't have to be an expert to make similar progress. This is doable! Here are some tips for everyday homeowners and renters. I'll give you some useful links at the end.
Here, in sum, are some principles to go by. More on each below.
Set your goals
Trust but verify
Break the process into smaller pieces and patiently chip away
Some of the most boring measures are the most impactful
Size does matter ... at least when it comes to heating and cooling systems
Electrification doesn't have to be excruciating
Choose contractors (very) carefully
Energy efficiency improvements will save you more money than you think (or that your contractor tells you)
Electrify your ride to save money and trim emissions
Solar last, not first
Grab the large and abundant cash incentives available in many areas (no one will tell you about them)
How you live is just as important as how your house is built and what kind of cars you buy
But, remember, it's not all about the money
Learn more
Set your goals
There are many worthwhile reasons to improve one's home's energy and carbon performance. Among these are saving money, reducing pollution, improving comfort, raising resale value, becoming more resilient in the event of power outages, etc. Think deeply about this before jumping into your project. Not all reasons may apply to you ... and that's fine.
Think also in terms of concrete goals or targets. For example, do you want to simply reduce your energy bills (or are you perhaps even willing for bills to go up a bit in the name of achieving other goals)? Do you want to reduce greenhouse-gas emissions? For any goal, try to specify the degree of your aspiration, e.g. "carbon neutral" (zero emissions). There is no right answer to these questions, but you need to have goals and targets in order to make good choices and be clear with designers and contractors how far you want to go.
Are there any things you're categorically opposed to (e.g. electric cooking or heatpump air distributors hanging above doors and such, like you see in hotel rooms).
Do you seek/require a certain return on your investment? If so, spell that out. Again, there are many ways to verbalize this including a payback time on your investment expressed in years, a certain percent-per-year return on what you invest in the improvements, or a lifetime cost of energy+improvements (aka "lifecycle cost") that is lower than if you do nothing. Be sure that any incentives are subtracted from the gross costs before you do the math.
Trust but verify
To identify opportunities, it's usually important to get an energy audit. As part of this process, there are well-refined tests you can (and should) have done. A "blower door test" will quantify your home's leakage, and, so cool, once it's running, workers can more easily find and seal those leaks and see in real time how much it helps. Similarly for ducts, find a provider who offers "duct blaster" testing -- again, they can find and seal leaks while on site and actually measure how effective their efforts are. A good auditor will also run a computer model based like the Home Energy Score on the specifics of your home and generate a list of ranked efficiency improvements. This is information you can later take to your contractor.
Break the process into smaller pieces and patiently chip away ... many opportunities don't require contractors
There is no need to do it all at once. Be opportunistic: when an appliance fails, shop intensively for the most energy-efficient unit you can find. These "windows of opportunity" only open briefly, then closing again for many years before the next replacement. Similarly, many remodels offer the opportunity to upgrade insulation and such. Many efficiency improvements are achieved through steps you take on your own (not with a contractor). Think about lights, appliances, computer displays, TVs, printers, etc. Always find the energy ratings and consider them in your purchase selections.
Some of the most boring measures are the most impactful
Many homes lose 1/4 of their heating energy through air leakage around windows, doors, electrical outlets, etc. A similar amount can be lost through leaky ducts. Another everyday opportunity is replacing lights with LEDs and old appliances with premium-efficiency appliances ones.
Size does matter ... at least when it comes to heating and cooling systems
The sad truth is that contractors have a conflict of interest: larger units generate more profit and lower risk of complaints, and it takes them less time to do "curbside sizing", meaning educated (?) guessing. Oversizing also means more pressure on your electrical panel (a tight constraint in many cases) In the US, there is a very straight-forward sizing process called "Manual J" that you should insist your contractor do. If they don't know about it or how to do it, they shouldn't be touching your house. It should take them about 30 minutes after you give them the needed info -- a small effort for such a costly project.
Electrification doesn't have to be excruciating
The only way to zero emissions is through the power lines carrying renewably generated electrons (unless you're off-grid altogether, but, still, it requires that electricity is the only on-site energy source). The first obstacle most people run into in existing homes is claims from the electrician that major panel upgrade is required. There are lots of interesting strategies for eliminating the need for costly panel upgrades. For example, the 120v/15A washer/dryers and heat pump water heaters, "dimming car chargers", prioritized circuit-sharing devices, etc., are cost-effectively helping people avoid having to do panel upgrades. If electricians tell you need a panel upgrade, ask them to first determine your actual peak demand and to identify what measures you could take to have the changes you want within the capacity of your current panel. With methods shown in this useful document, most homes can actually fully electrify on a standard 100-amp panel. See resources at the end for tools and tips.
Choose contractors (very) carefully
As with any home-improvement project, there are too many workers running around who are not qualified, don't communicate well, and aren't really interested in improving homes' performance. Interview carefully. Ask if they have experience doing the types of energy improvements you're seeking. Ask if they can tell you about available incentives in your area. Ask if they have any specialized trainings and certificates relevant to your project needs like those offered by the Building Performance Association or the LEED program. Rinse, repeat.
Home energy efficiency improvements can save you more money than you think (or that your contractor tells you)
You'll probably find that utilities, carpenters, and others are poor at best in giving you a concrete idea of how much energy (and money) you can save. Push them. In addition to simple factors like gallons of gas x $/gallon, there are many more subtle sorts of savings you can capture. The above-mentioned energy audits can help with this.
It's important to look for whether you qualify for a more advantageous utility rates. Most utilities give lower rates for all-electric homes or owners of electric vehicles. These often result in giant savings on your bills! And, if you are on an increasingly common "time-of-use" rate, simply shifting your use (think clothes-drying or car-charging) to "off-peak" periods can save you 30% to 50% on that energy use.
Electrify your ride to save money and emissions
Don't fall for the culture-war spin that EVs emit more carbon to make and drive than gas cars. Your EV will "pay back" its emissions within the first year or two, and fastest if your home is solar or you live in a cleaner grid. EVs save more energy and emissions than plug-in hybrids. And, did you know that preferential electricity rates for EV owners can reduce electricity costs for your entire home?
Solar last, not first
Prioritize saving as much energy as possible (appliances, lighting, heating, etc.) because that will mean (a) a potentially much smaller/cheaper solar system if you do indeed go that route or (b) you'll have minimized the amount of clean power (and thus $) you need to buy from the utility. Beware that solar system designers typically lazily size your system to match your current electricity use, which means it will be oversized if you later improve energy efficiency ... or it could be undersized if you later add major electricity uses, like electric car charging or a hot tub. Our home did not have solar access, so we are buying a the small amount of power we now need from our utility instead. Same kinds of panels, just located elsewhere.
Grab the large and abundant cash incentives available in many areas (no one will tell you about them)
In many parts of the country, utilities are offering very significant financial incentives in the form of rebates. The "professionals" helping you will usually be unaware of them. Sometimes a certified installer has to be used in order for you to qualify, so check into that before signing contracts! There are significant federal tax incentives, too, which can also amount to many thousands of dollars that you can discount from your annual tax bill. And, starting in 2024, electric vehicle incentives (up to $7500) can be deducted from the car's sales price -- no waiting for tax refunds! The incentive landscape is ever-changing, and this can be frustrating. Be sure to get the latest info before making decisions.
How you live is just as important as how your house is built and what kind of cars you buy
Many lifestyle factors impact energy use as much as "tech" does. Think about the temperatures you keep your house at (while home, while sleeping, while away). Lights on when no one is in room? Driving when you can bike or walk? Lots and lots of little ways to save, at zero cost.
But, remember, it's not all about the money
Many energy-efficiency measures have non-monetary benefits. Your house will probably be more comfortable after upgrading cold windows. Your LED lights will last way longer than the old incandescents or fluorescents. Your new, efficient fridge will be quieter than the old one. Your induction cooktop will eliminate dangerous indoor pollutants. Your EV will be more responsive and feel safer, and "filling up" at home while you sleep beats standing around a stinky gas pump instead of having a latte.
And, since homes and cars are responsible for about one-third of national greenhouse-gas emissions from energy, doing your part does, actually, make a difference ... and that means profit for the planet.
Learn more: Here are some helpful resources
Financial incentives
The federal ENERGY STAR program offers an on-line resource about federal tax credits. More info from the IRS.
The Switch is On offers an electrification rebate finder that covers local, state, and federal incentives.
Inflation Reduction Act (IRA) - this is only the national program, doesn't include state and local incentives.
A group called Quit Carbon helps California homeowners develop "electrification plans". Here's their list of incentives.
If you live in California, the Energy Smart Homes Program will give you thousands after eliminating your final gas appliance. Look for similar programs in other states.
Database of State Incentives for Renewables and Energy Efficiency : https://www.dsireusa.org.
Purchasing and everyday decisions
The ENERGY STAR website has comprehensive lists of the most efficient appliances and equipment, plus resources if you're building a new home
Tips and other useful info from the federal Energy Saver website
Find a local company that can give you a Home Energy Score -- this will rate your home's efficiency and make recommendations
Home electrification
Extensive tech tips from Redwood Energy on clever ways to electrify without breaking the bank
Electric cars
See every EV rated, plus other helpful decision-making resources at https://fueleconomy.gov/
For technically-oriented homeowners
A no-cost "Manual-J" calculator for heating and cooling system sizing is called CoolCalc
The Watt-Diet Calculator helps you figure out whether there is room in your panel to electrify without a pricey panel upgrade
There are a number of good books out there, including:
No Regrets Remodeling (2nd Edition free here)