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 produce 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. There've been a lot of successes as I’ve worked toward my net zero energy goal, a lot of learning … and some hiccups and setbacks too. It’s been a real watt-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 of 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. You can watch the playlist I’ll link to here and in the description.
In a nutshell, my wife and I outgrew our previous house and I suggested that we try building a home using all the tech and techniques 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. 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 (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 TL;DR 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 about energy use and efficiency. The other will be focused on our energy generation and how that’s worked out.
What about the challenges? Well, most of the issues that have come up all tie back to some of the construction decisions 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 build so we could put that money into other features we wanted more.
We decided to go for a slab-on-grade foundation — basically, we built a house with no basement. So, if we ever need to hide from zombies, we’ll have to get creative. While there’s nothing wrong with slab-on-grade, it does complicate some things.
You really have to plan ahead for how and where you’re going to run HVAC ductwork, plumbing, electrical, home networking, and so on. You want to limit how many intrusion points you have through the thermal envelope of your house. With a basement as part of your thermal envelope, you have an easier time routing all of those things under the main floor … and adding on to them later.
We had to plan for all of that upfront, which does limit how easily we can modify things later without puncturing that airtight thermal envelope. One issue that I discovered more recently was a mistake or miscommunication between my general contractor and the roofers when building my house. According to the construction documents from Unity Homes, my roof should have had ridge vents along all the sections of the house.
This is important to ensure proper airflow within the attic spaces to prevent humidity build up. Hot, moist air exhausts through the ridge vent at the top of the attic space, while fresh outside air comes in through soffit vents 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 and my studio & 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 in the different areas of my attic space 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 my HVAC system and ERV to get consistent CO2 levels throughout the house. Me being me … I have temperature, humidity, and air quality sensors everywhere. I have a dashboard built out in Home Assistant, so I can see how all of this looks over time.
It’s been super helpful. I’ll get into those results in just a minute though. The biggest challenge, which I’ve talked about in 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 specifically in the followup video. So, how do the results for the house look at a high level?
Before getting into those results, there’s another tool 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 everything else you have to do with 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 . .
. sometimes they sell your info to some pretty shady people. Or they can fall victim to data breaches that leak your data to scammers.
Incogi can help 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 Icogni, gave them the legal right to work on my behalf, and then … just sat back and relaxed.
You’ll see updates on your account for which data brokers they’ve sent legal requests too and which ones have complied. It couldn’t be easier. Incogi really has been helping me.
If you want to take back some of the control around who has access to your personal information, give Icogni 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 of my house are looking at a high level. I 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 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 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. Bad timing. Setting that aside, the most important thing for any house when it comes to maximizing your energy savings is its general efficiency.
How good is the insulation and air tightness of the home? For a building to hit the passive house standard of airtightness, you have to achieve a pressure test of 0. 6 air changes per hour or lower at 50 pascals of pressure (referred to as ACH/50).
We achieved a blower door test just below 0. 6 ACH/50 during a mid build test, and got very close to that again in the final blower door test. Now make no mistake, this isn’t a passive house certified home — that was never my goal.
But it is much closer to that level of home than a “to code” built house. The insulation level of our walls is R-35 along with triple glazed, tilt turn windows, which are super efficient. And I believe the attic has an R value of around R-60 or R-65.
To say this house feels consistent temperature-wise would be an understatement. There’s no cold spots or warm spots. It’s also very quiet in the house.
While my wife was under the impression that this house would be a tomb when it comes to noise, that’s not the case. We can still hear the loudest trucks as they drive by on the road behind our house, but it’s very muted. This is hands down the quietest house I’ve lived in.
My WaterFurnace geothermal HVAC system has taken a little getting used to. I’m more accustomed to the standard forced air systems that you typically see here in the US. 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 energy.
Well, with a geothermal system, you don’t really 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. 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. 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. My wife and I decided to take a “set it and forget it” approach for the first year in the house. We set the desired temperature range to 72 to 75 F (22 to 23 Celsius) and just let the system take care of itself.
I did try setting the HVAC fan to specified run times to try and cut down some energy use. However, our Energy Recovery Ventilator (ERV) setup complicated this. One of the challenges with a super airtight house is how to control cycling in fresh outside air while exhausting stale inside air out.
You don’t want to lose all that energy you put into heating and cooling your inside air as it leaves your house. The ERV does this by exchanging that heat between the inside and outside air before it comes into the house. Inside and outside air pass through little microchannels running alongside each other to make this happen.
The ERV has dedicated exhaust vents in certain areas of the house. However, the ERV air pulled in from the outside doubles up on the HVAC system’s ductwork vents to distribute it throughtout the house. An ERV having its own dedicated lines for both intake and exhaust gives you a lot more control and is ideally what you want.
The way mine is set up definitely works, but some of the 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.
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 hardhats, 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 compared it to our previous house and community averages. For energy tracking I have a Span smart electric 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 WaterFurnace’s Symphony app or my Rheem water heater’s EcoNet app, but I really only used 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 to what I’m about to share is that it 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 with the opposite panel. It wasn’t a Span problem, but a problem when the electrician first set them up in the app.
It meant the numbers were all screwed up for about six weeks. That got corrected in October. Just in time for Halloween, because nothing’s 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 1. 6%, which is much lower than I expected. Considering the average US household has about 54% of their electricity use going towards heating and air conditioning, my 15.
4% seems REALLY low. But what the heck is going on with my network closet? It's like the Bermuda Triangle of energy use!
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 (NVR) with a bunch of Unifi Protect security cameras around the outside of the house, and Qnap network attached storage (NAS) for archiving all of my video footage used in my videos. Basically, I run a business out of my home, so there’s a lot of gear in there that the average house isn’t going to 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’m going to be trying to get it 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 at 3. 5% And the ERV at 2. 3% My heating and air conditioning still comes in well under half the typical house.
I don’t have good data for my previous house as a comparison for a pretty dumb reason. I forgot to export my Span smart panel data from the 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 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, air-tight house. And for those of you wondering what “heat backup” is? I have no idea (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 actually is considering 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 (1 Therm = 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 we used in the old house to generate hot water. That’s just nuts. What would I have done differently?
Nothing too dramatic, but I have wondered if it would have been better if we had opted for a basement. It would have simplified a lot of the headaches we ran into trying to preplan all of the HVAC, electrical, and networking runs. It would also have given us easier access to make modifications to that stuff over time without having to worry about possibly compromising the air-tight envelope.
Another would-be bonus: extra climate-controlled storage space … but maybe it’s a good idea we don’t have that. Keeps us from turning into contestants on “Hoarders: 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 you’ve probably seen if you’re subscribed. Speaking of subscribing, I know from my YouTube analytics that a significant number of you that watch on a regular basis still aren’t subscribed, or 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 we’ll hopefully be here for decades. Spending a little more upfront 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 at least with a quality air source heat pump setup because it’s just going to blow away any natural gas or standard electrical system you can get. Granted, electricity and natural gas prices will vary how much of a financial gain you’ll get in that equation, 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.
Drers 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 (~3000W vs. ~800W), 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 the clothes 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 of recommending a “heat pump all the things” 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 the geothermal system is incredible. 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 it. 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 ever used, so again, I highly recommend it. Faster cooking 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 random capacitive buttons as she walks across them. 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 year, I’ll be getting into that in a separate video.
I kind of need that to give the final assessment of “was this 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 weight to help me achieve that net zero energy goal. But what do you think?
Do you have any experiences you can share using similar tech or approaches? Jump into the comments and let me know and be sure to listen to my follow up podcast Still TBD where we’ll keep this conversation going. Thanks as always to my patrons for your continued support … you really help to keep this channel going.
I’ll see you in the next one.
