Your Energy-Efficient Custom Home: Priorities to Consider
Last week’s winter snow storms were intense, especially in Texas with the rolling blackouts. Because of this, I want to talk about energy efficiency and how it relates to your custom home. It should be a priority for you, whether high or low, because once your house gets designed—and especially once you detail all the specifications—it’s difficult to go backwards and catch up. So, if you can, I’d like for you to define your level of priority for energy efficiency in your home before getting started.
Personally, I break energy efficiency down to three levels. Let’s take a look at each in more detail...
Level One: Code Minimum
The first level is code minimum. The energy codes have changed in ten years—and significantly again over the last two years. There was a big energy code revision that happened and there's another one coming in two years. Many of these energy efficiency minimums rely on which zone you live in. The US is broken down into somewhere around eight zones, all indicating how cold it gets where you live. In a nutshell, the number goes up the farther north you go. For example, here in Dayton, Ohio, we’re in zone five. So, in zone five, our ceiling minimum is R38. But if you went to zone six, your ceiling minimum goes up to an R49. Now, I know what you’re thinking: What does the R stand for? R values are the insulation value—the higher, the better. You might also see a U value, which is the inverse of R. Those are the two options of how we rate insulation.
Level Two: Hybrid
The second level is where most of my clients fall—they’re really interested in net zero. However, after more thorough investigation, it's not that they necessarily want that certificate, it’s more that they want to be very energy efficient and to produce some energy so they can replace what they're using. For this level, not only do you need to hit your code minimum, you have to consider different impacts: energy impact and financial impact.
Interior Insulation
First, let’s talk about interior insulation. Ceiling insulation is something you absolutely need. It also happens to be the easiest and least expensive place to bulk up your insulation value. You'll also want to consider Flash & Batt, which is a wall insulation system. For example, if you have two by six walls, you do two inches of Spray Foam Insulation and then you do batt insulation on top, which gives you the best of both worlds. The spray foam insulation seals everything and it's a really high R value. But keep in mind, spray insulation is very expensive, so only doing a two-inch layer is less expensive than filling the entire cavity. Many people don’t take me up on this, but insulation under your basement slab is so important. Ground temperature is a constant 50 degrees. Above the slab is your home temperature at 70 degrees. With all of these layers, your home is trying to find its “normal” temperature. So, if your house is set to 70, it’ll keep getting colder until it meets 50 degrees. The bottom line? That slab is a continuous suck on your home room temperature, constantly draining heat out. By putting a two-inch rigid insulation under the slab, it's going to keep more heat on the top side and keep more cold on the bottom side. And it's not super expensive either (possibly a few thousand dollars). It's an investment that you’ll hopefully never have to touch again.
Exterior Envelope
Next, let’s talk about exterior materials, especially an exterior insulation finish system, or EIFS. You'll see it when you go past construction sites, where it looks like they put sheets of rigid insulation up on the side of your house, and then they stucco over it. This is a great system because it's a continuous barrier. If you think of your stud walls, you have studs every 16 inches. That stud is a bridge for thermal transmission, and that means your heat is going from inside your house to outside of your house. Walls are not a huge heat loss place, but if you've already addressed sealing the attic space, then the walls are a good place for additional insulation.
You’ll also want to research your windows thoroughly. Windows are a big number for energy efficiency, so it’s worth every penny. But it's also a balancing act: Do you save money now and sacrifice the R value over the long term? Or do you put the money in now? Take your time to decide. It's not just what the windows look like or what color they are, but what their insulation value is—which is readily available on Google!
Home Systems: Water Heaters, Geothermal Energy & Solar Power
The third thing to consider are systems like your water heater, which wastes a lot of energy by simply keeping water hot all the time, and geothermal energy. The government is up and down and back and forth about whether they should give tax credits for this or not. So, do your research and know your deadlines. Sometimes your entire geothermal system has to be installed by the end of the year for you to get the tax credit, and if you miss that deadline, you don't get money. In fact, it may be 15 to 30 years before you recoup that money, because studies are still up in the air around maintenance costs. So, be careful with geothermal.
Lastly, you’ll most likely consider solar power, which doesn't work when snow is on top of the panels or when you don’t have the correct sun orientation. So, sometimes solar can be dicey, but definitely worth researching. When all else fails, hire a specialist to hammer out all of the details and see what's right for you!
Level Three: Certified Levels
The third level takes into account your certified levels. In a nutshell, governing agencies like Energy Star, LEED, and Net Zero are able to give you a certificate for a gold level, silver level, or bronze level. If you’d like to be certified, Springhouse can help you through that process, but keep in mind, I’m not certified.
Basically, you’ll need to hire a specialist, like an architect or builder, to come in the very beginning of the process and talk about what's important to you.
Have any questions?
It’s no secret that energy efficiency is a big topic. In fact, we’ve just brushed the surface. But getting your priorities in line before you design and work through all of the detailing of your construction documents is incredibly important. If you have any questions, pop by Springhouse Collaborative, our free Facebook Home-Building Community! We’re excited to meet you.
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