What I Learned After 1 Year in My Net Zero House

If you've been following my channel for a while, you'll know that I built my forever home with the goal of reaching net zero energy status. In other words, I wanted my home designed so that I produced as much energy as I use over the course of a year. To get there, I incorporated a bunch of gadgets and techniques into my plans, like solar panels, home batteries, a geothermal heat pump, airtight house construction, and much more. Well, it's been a full year since I moved in, and there's been a lot of successes as I've worked towards that net zero energy goal. A lot of learning, some hiccups, and some setbacks too. It's been a real watch and see kind of journey. So if you want to make your home more energy efficient, what should you look out for and what strategies should you try? And then there's the lingering question, was all my effort really worth it in the end? I'm Matt Ferrell ... welcome to Undecided. This video is brought to you by Incogni, but more on that later. I won't rehash the whole house build story, but you can watch that playlist that I'll link to in the description. In a nutshell, my wife and I outgrew our previous house, and I suggested that we try to build our own home using all the techniques and technologies that I've been talking about on the channel for the past several years. Basically, I wanted to walk the walk and see how well a lot of this stuff actually works for myself. So here's a rapid fire list of what that entails. A factory built home from Unity Homes with incredible insulation and air tightness. A geothermal HVAC system for heating and air conditioning. Air source heat pump water heater tied into the geothermal HVAC system. An energy recovery ventilator, or ERV, as the lungs of the house. High efficiency appliances like our washing machine, ventless heat pump dryer, refrigerator, dishwasher, and induction cooktop. And of course, solar panels with home batteries for energy generation and storage. Before I get into all the nerdy details of what's happened, what's worked, and what hasn't, the TLDR for my home is that we're extremely happy with this place. It's not perfect, and there are things I would have done differently, but this home has been fantastic for us. This is also being broken up into two videos. This video is all about the energy use and efficiency. The other will be focused on our energy generation and how that's worked out. So what about the challenges? Well, most of those issues that have come up all tie back to some of the construction decisions that we made two, three, or even four years ago when this all started. For instance, we wanted to save some money on different areas of the builds so that we could put that money into other features that we wanted more. We decided to go for a slab-on-grade foundation. Basically, we just built a house with no basement, so if we ever need to hide from the zombies, we'll have to get a little creative. While there's nothing wrong with slab-on-grade, it does complicate some things. You really need to plan ahead for how and where you're going to run HVAC duct work, plumbing, electrical, home networking, and so on. You need to limit how many intrusion points you have to the thermal envelope of your house. With a basement as part of your thermal envelope, you have an easier time routing all those things under the main floor and adding onto them later. We had to plan for all of that up front, which does limit how easily we can modify things later without puncturing that airtight thermal envelope. One of the issues that I discovered more recently was a mistake or miscommunication between my general contractor and the roofers when they were building my house. According to the construction documents from Unity Homes, my roof should have had ridge vents all along the sections of the house. This is important to ensure proper airflow within the attic spaces to prevent humidity buildup. Hot, moist air exhausts through the ridge vent at the top of the attic space, while fresh outside air comes in through the soffit fence lower down. Nobody wants black mold growing in their attic space. Well, the roofer only put a ridge vent along the top of the main living area of the house. They didn't do it along the connector or above the garage in my studio and office. As soon as I spotted the issue, I let our contractor know and they're in the process of making it right. By the time you're seeing this, the roofers are coming back and adding those vents. But in the meantime, I stuck some humidity and temperature sensors into the different areas of my attic spaces and confirmed that there's a distinct difference when there's proper venting. The main area of the home with the ridge vent has a smaller temperature and humidity gradient than the other attic spaces, and it also runs with a lower humidity and temperature level overall. There was also a learning curve around the best way to run the HVAC system and ERV to get consistent CO2 levels throughout my house. Me being me, I have temperature and humidity and air quality sensors everywhere. I have a dashboard built out in Home Assistant so I can see how it looks over time. It's been super helpful. I'll get into those results in just a minute though, because the biggest challenge, which I've talked about in my previous videos about my solar and battery setup, was just getting the solar and battery stuff installed. My solar didn't get activated until October of last year, and my battery didn't get installed and turned on until May of this year. I'll be getting into how the solar is working out specifically in that follow-up video. So how do the results for the house look at a high level? Well, before getting into those results, there's another tool that I've been using that's been getting fantastic results for me, and actually helped out a lot with our move into this house. That's protecting your online privacy with today's sponsor, Incogni. As my wife and I were getting our house constructed, setting up loans, getting insurance, and all the other stuff you have to do when you're moving, I saw a major uptick in the amount of spam promotional emails I was getting. I'm sure you've experienced this kind of thing too. That happened because companies sold my information to data brokers, and sometimes they sell your info to some pretty shady people. Or they can fall victim to data breaches that leak your data to scammers. Incogni can help you with this. We have the right to request that data brokers delete our information, but it takes a lot of time and effort. I signed up for Incogni, gave them the legal right to work on my behalf, and then just sat back and relaxed. You'll see updates in your account for which data brokers they've sent legal requests to, and which ones have complied. It couldn't be easier. Incogni really has been helping me. If you want to take back some of the control around who has access to your personal information, give Incogni a try. Take your personal data back with Incogni, use code UNDECIDED at the link below and get 60% off an annual plan. Thanks to Incogni and to all of you for supporting the channel. So back to how the results are looking for my house at a high level. We need to address the elephant in the room first, which is the cost of the house. I'm not going to share the exact costs of building the house, because the real estate and building costs vary state to state and town to town by so much. However, percentage wise, we paid roughly 25% to 30% more per square foot than a traditional house that's built to code standard. It's difficult to nail that down specifically though because of when we built it. It just so happened to be during the initial surge in pricing that we saw during the pandemic. That's really bad timing. Setting that aside, the most important thing for any house when it comes to maximizing your energy savings is general efficiency. So how good is the insulation and air tightness of the house? For a building to hit passive house standard of air tightness, you have to achieve a pressure test of 0.6 air changes per hour or lower at 50 pascals of pressure, referred to as ACH50. We achieved a blower door test just below 0.6 ACH50 during a mid-build test and got very close to that again in the final blower door test. Make no mistake, this is not a passive house certified home. That was never my goal, but it was much closer to that level of a home than a two-code built house. The insulation level of our walls is R35, along with triple glazed tilt turn windows, which are super efficient. And I believe the attic has an R value of around R60 or R65. To say this house feels consistent temperature wise would be an understatement. There are no cold spots or warm spots. It's also very quiet in this house. While my wife was under the impression that this house would be a tomb when it comes to noise, that's just not the case. We can still hear the loudest trucks as they drive by on the road that's behind our house, but it's very muted. This is hands down the quietest house I've ever lived in. Now, my water furnace geothermal HVAC system has taken a little more getting used to. I'm more accustomed to the standard forest air systems that you typically see here in the U.S. Typically you have a smart thermostat where you adjust timers, temperature, and fan settings dependent on whether people are home or not, like dropping the heat if the house is empty, or even dropping the temperature at night during the winter to save some energy. Well, with a geothermal system you really don't want or need to play the thermostat game of how low can you go. It's more of a set it and forget it situation, like Ron Popeil's rotisserie, but with less infomercial flair. Turn it on and you set it and forget it. Now, it's better to let the geothermal ground loop get equalized and just run. My geothermal well is a single loop going down about 400 feet into the ground in my backyard. Inside the house, heat is captured and cycled through the ground loop to cool things off for summer air conditioning, and in the winter the warmth of the earth is cycled into the house for heating. If you try raising and dropping the inside temps by time of day or by occupancy, it's going to take a longer time to ramp up to the desired temperature. The system is most efficient when it's running at temp. That means you'll be using more energy trying to race to a moving temperature setting versus just leaving it set for longer stretches of time. It's kind of counterintuitive. Now, my wife and I decided to take a set it and forget it approach for at least the first year of the house. We set the desired temperature range to 72 to 75 degrees Fahrenheit, which is like 22 to 23 degrees Celsius, and just let the system take care of itself. I did try setting the HVAC fan to specified run times to try to cut down on some energy use. However, our energy recovery ventilator setup kind of complicated this. One of the challenges with a super airtight house is how you control cycling in fresh outside air while exhausting stale inside air out. You don't want to lose all that energy that you put into heating and cooling your inside air as it leaves your house. The ERV does this by exchanging the heat between the inside and outside air before it comes into the house. Inside and outside air pass through little micro channels running alongside each other to make that happen. The ERV has dedicated exhaust vents in certain areas of my house. However, the ERV air that's pulled in from the outside doubles up on the HVAC system's ductwork vents to distribute it throughout the house. An ERV having its own dedicated lines for both intake and exhaust gives you a little more control and is ideally what you want. The way mine is set up, it definitely works, but some of that control is limited. What I found was that the ERV fan running at its normal low levels didn't have enough force to properly distribute the fresh air consistently throughout the house. The CO2 levels in some areas of the house would get a little higher than I'd like, so I ended up setting the HVAC fan to continuous so it's running 24-7 at a very low level as a baseline and it solved the ERV air distribution issue. I was concerned about how much energy this would all use, so how did that end up looking? Strap on your nerd hard hats, because I'm about to drop a lot of data and graphs on your head. I found the energy use of my house absolutely fascinating, especially when I was comparing it to my previous house and community averages. For energy tracking, I have a SPAN smart panel, so I have circuit-by-circuit energy use. Most of my appliances and systems also have their own energy use tracking as well, like Water Furnace's Symfony app or my Rheem water heater's Econet app, but I really only use those to verify my SPAN panel's numbers. I also have smart outlets and my SPAN integrated into Home Assistant, which adds yet another way I can track and double check my data. The one caveat I'm about to share is that this isn't a full year of data. It's only from October of last year because my SPAN panel setup had an issue for the first couple of months. Basically, my two SPAN panels were incorrectly associated inside my app. The app thought each panel's circuits were associated to the opposite panel. It wasn't a SPAN problem, but a problem when the electrician first set them up in the app. It meant that their numbers were all screwed up for about 6 weeks. That got corrected in October, just in time for Halloween, because nothing is scarier than inaccurate energy data. Let's look at the data I do have between October and now, or about 10 months worth. The top energy sinks of the house were my network closet at 19.2%, the geothermal system at 15.4%, charging my EV at 12%, a whole house dehumidifier at 5.5%, water heater at 5.2%, and the washer and dryer at 2.4%. The rest is made up of other odds and ends, but interestingly the ERV only accounts for about 1.6%, which is much lower than I expected. Considering the average U.S. household has about 54% of their electricity use going towards heating and air conditioning, my 15.4% seems really, really low. But what the heck is going on with my network closet? It's like the Bermuda Triangle of energy use. With that said, I would be lying if I said my network closet is normal. I have a server rack with multiple Ubiquiti network switches, a UniFi network video recorder with a bunch of UniFi Protect security cameras around the outside of my house, and QNAP network attached storage for archiving all my video footage that I use my videos. Basically I run a business out of my home, so there's a lot of gear in there that the average house won't have. I did manage to cut my network closet energy use by 35% a few months ago, and there's a few other things I'll be trying to get down even more. But if I want to compare my energy use in a way that's more apples to apples to a typical house, I need to remove my network closet and EV from the mix. If I do that, things change a bit. Now my geothermal system is at 22.3%, a whole house dehumidifier at 8.1%, water heater at 7.5%, the washer and dryer is now at 3.5%, and my ERV is at 2.3%. My heating and air conditioning still comes in well under half of a typical house. I don't have good data for my previous house as a comparison for a really dumb reason. I forgot to export my Span smart panel data from my old house before I lost access to that panel. Like I said, dumb. But I can do an apples to oranges comparison with just the amount of natural gas our old system used for heating alone. We averaged the equivalent of about 500 kWh a month for natural gas heat. My current geothermal average of about 193 kWh a month for heating and cooling, including the electricity to run the HVAC fans, is still only 39% of my old house's natural gas energy alone. That's the one-two punch of my geothermal system efficiency with a well-insulated airtight house. And for those of you wondering what heat backup is, I have no idea, at least not yet. But I do know that it's not directly related to my geothermal system. It's how it's labeled in the Span app, but I'm still trying to figure out what it is exactly because it's 4% of my energy use. What's even more interesting to me is my hot water. It's not only more efficient because it's a heat pump water heater, but it's also tied into my geothermal desuperheater. It's using the waste heat from the HVAC system to help preheat water into a holding tank. On average, we're using about 65 kWh a month for hot water. In my old house, we used natural gas, but you can convert gas therms to kWh, because one therm is about 29.3 kWh. On average, we used the equivalent of 398.9 kWh per month. That means we're using only 16% of the energy that we used in the old house to generate hot water, which is just nuts. So what would I have done differently? Well, it's nothing too dramatic, but I have wondered if it would have been better to opt for a basement. It would have simplified a lot of the headaches we ran into trying to pre-plan all the HVAC, electrical, and networking runs. It would have also given us easier access to make modifications to the stuff over time without having to worry about possibly compromising the airtight envelope. Another would-be bonus? Extra climate controlled storage space. But maybe it's a good idea that we don't have that. It's keeping us from turning into contestants on Hoarder's Net Zero Edition. As much as I love our geothermal system, it was pretty pricey. I have details on that in my previous geothermal video that you've probably seen if you're subscribed. And speaking of subscribing, I know that for my YouTube analytics, that a significant number of you that watch on a regular basis still aren't subscribed. Or you thought you were, but actually aren't. I hear that a lot from some of you. Subscribing and hitting the notification bell not only helps you not miss a video, but it also helps out the channel with the mighty YouTube algorithm gods. As far as the geothermal cost, we were building our forever home and will hopefully be here for decades more. Spending a little more up front to get the long term benefits was worth it to us, but your mileage will vary there. Air source heat pumps are absolutely superb today. And yes, they do work in the cold. I'd recommend going with at least a quality air source heat pump setup because it's going to blow away any natural gas or standard electric system you can get. Granted, electricity and natural gas prices will vary how much of a financial gain you'll get but you will come out ahead over time. It's just by how much that's the open question there. I'd also strongly recommend a ventless heat pump dryer if you can find one that fits your needs. They're dramatically more efficient than a standard electric dryer. My wife and I are using about 31 kWh on average per month running both our washing machine and heat pump dryer. Dryers that vent outside of your home are ejecting a lot of conditioned air from inside your home. Not only is it using more electricity than a heat pump dryer, which is about 3,000 watts versus about 800 watts, but it's forcing your HVAC system to work harder to recondition your home. Yes, a heat pump dryer may take a little more time to get your clothes as dry as you like, but it's using a fraction of the energy and not exhausting conditioned air outside your house on top of that. And to continue my trend recommending heat pump all the things kind of a strategy, I'd also highly recommend going with a heat pump water heater when it's time to replace your old one. You can check out my previous video on the ins and outs of them, but in a nutshell, they work well and will save you a lot of energy and money. Mine paired with my geothermal system is absolutely incredible and I'm really happy with the results. Lastly, we're also really liking our induction cooktop. I've talked about these in a previous video too, but after living with one for the past year, I love this thing. It heats up far faster than any other electric cooktop I've ever used. And much like cooking with natural gas, when you turn it off, it's off. It brings a pot to a boil faster than any stove I've used, so again, I highly recommend it. Faster cooking times means less time running and using electricity. It's also a great warning system for when my cat is walking across the counter. Her feet activate the random capacitive buttons as she walks across them, so when we hear a random beeping, we know it's her. As for my goal of hitting net zero energy, meaning generating as much energy as I use over the course of a year, I'll be getting into that in a separate video. I kind of need that to give the final assessment of was it worth it. So be sure you're subscribed with notifications to not miss that one. But from a more anecdotal point of view, this is the most comfortable and quiet house I've ever lived in. I can say now that my house is super energy efficient, so it's definitely pulling its own weight to help me achieve that net zero energy goal. But what do you think? Do you have any experiences that you can share using similar tech or approaches? Jump in the comments and let me know. And be sure to listen to my follow-up podcast, Still To Be Determined, where we'll keep this conversation going. And thanks as always to my Patrons for your continued support. Your help really keeps this channel going. I'll see you in the next one.