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 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.