14 Ways One LA Designer Created Eco-Friendly ‘Granny Flat’

by on September 16, 2021 · 2 comments

in Environment

From LA Times:

Sustainable builder Steve Pallrand, founder and principal designer of the L.A. firm Carbon Shack Design, designed and built an 888-square-foot zero energy accessory dwelling unit, or ADU.

“To make sure the systems he puts into place tread lightly on the planet, Pallrand added many eco-friendly solutions: Wood from the dilapidated barn was saved to frame the interior non-structural walls of the ADU. The barn’s redwood siding was reused on half of the house and new redwood siding was added to finish the rest of the exterior. Old roof sheeting was reused as flooring. Board-and-batten barn siding was used to make the cabinets and millwork. The concrete slab was broken up and used as pathways, and when the city forced them to remove a cedar tree for fire access, they used it to create live edge countertops and furnishings in the kitchen.”

Pallrand details his strategies for creating environmentally friendly housing that will help fight climate change:

1. Plug it in

The best way to reduce your operational footprint is to have an all-electric house. This project has a solar array on the roof, but even if you can’t produce your own electricity, getting rid of gas appliances still makes environmental sense as most utility grids are getting greener, phasing out coal and relying more on wind, solar and other renewable sources.

2. Creative cooling

At least half of the energy used in a house goes to heating and cooling. In this project, we used heat pumps that heat and cool with electricity only. Air-conditioning is already done by electricity but heat pumps heat with electricity as well. Basically, it is an AC unit running backward. Heat pumps are more efficient since they rely on heat exchange and so are more cost-effective.

3. In hot water

Heating your water is another major source of energy use in a house, accounting for approximately another 20% of usage. We have been taught that getting rid of the old gas-tank hot water heater and replacing it with a gas tankless is a more efficient use of energy. This is true, but you are still left with the fact that gas is a non-renewable resource. Heat-pump hot water heaters are electric units that use heat-exchange technology to heat water much more efficiently. They are more expensive than a traditional gas-tank hot water heater, but switching to a heat pump hot water heater will easily pay for itself within years and most certainly over the life of the unit and, most important, it is another way to easily get to an all-electric house.

4. All-electric kitchen

Why is a kitchen so hot when you’re cooking? It’s because only about 30% of the energy produced by burning gas is used to cook. The rest goes to heating your air, making life miserable and a complete waste of a non-renewable resource. Induction cooktops use electromagnetic energy delivering 80% to 90% to the cooking vessel. They are more efficient, make for a cooler kitchen, and has anyone thought about the environmental costs of living in a small refinery? One of the largest sources of indoor air pollution is the inefficient burning of fossil fuels in your kitchen.

5. Harness the sun

The roof on this project was tilted slightly to the south and is a single flat plane to maximize the number of solar panels. Enough panels were installed to reduce the operational energy footprint of this all-electric house to zero, but with so many panels the ADU became a net energy producer, offsetting the energy use of the main house as well as the pool equipment.

6. Water efficiency indoors …

We pay a water bill but we rarely think about how costly water is environmentally. Transporting it, refining it and treating the sewage takes a lot of energy. Reducing water use is not just critical as our water supply in Southern California shrinks but also because of the massive amount of energy it takes to get water over mountains and across huge distances to our taps.

Low-water appliances and plumbing fixtures are readily available and not like they were when first introduced. Government agencies require low-use fixtures for commercial buildings, and manufacturers are eager to make those products more pleasing and acceptable to the residential market as well. Low-flow showerheads and single-gallon flush toilets are much, much more efficient and pleasant to use than they used to be.

We also used motion-control water faucets in the bathroom [which conserve water by automatically shutting off when not in active use]. Washing your face and hands or brushing your teeth while leaving the water running wastes an astounding 4 gallons each time.

The main complaint regarding these fixtures is not knowing where the sweet spot is to trigger water flow. This is because our primary experience is in commercial situations where each building has a different faucet manufacturer. When it is your faucet that you use every day, you quickly know exactly how to use it. We do not use them in kitchens as trying to find that sweet spot when washing a head of lettuce is impossible. Instead, we install touch-on-off faucets in kitchens to reduce water use and which are wonderfully convenient when you are cleaning meat or fish and don’t want to touch the tap.

7. … and outdoors

We installed California native drought-tolerant landscaping along with a drip irrigation system that responds automatically to weather changes and detects and shuts off or alerts the owner when there is a leak. We also added rain capture cisterns to the downspouts to reuse rainwater for the landscaping.

8. Start with the foundation

Concrete is responsible for large amounts of carbon emissions (the production of cement is the carbon-intensive part), so the house was designed to sit above the ground rather than down at grade. This is because the ground rises toward the back of the site and in order for the structure to be at grade a concrete intensive slab and retaining wall would have had to be poured. Instead, we elevated the house above the grade, allowing us to use less concrete. We used a perimeter foundation, point loads and a raised wooden floor. To create the desired link to the exterior we used the wraparound deck and an “invisible” corner, two sliding glass doors meeting at and opening up the corner.

9. Salvage materials

The new building occupies the spot where an original 110-year-old dilapidated barn once stood. We took the old structure apart but, instead of throwing it in the dumpster, we found ways to reuse most of the materials, thereby reducing the need for as much new material and reducing the overall carbon footprint of the structure.

10. Shop local

No house can be completely built from recycled materials. New materials, like tile, always have to be purchased, so our mantra is to shop local. The carbon cost of shipping consumer products around the globe on polluting container ships is a major source of unregulated greenhouse gases. Chances are if you buy products made in the States they will have been produced under local environmental regulations and most certainly took less energy to bring to your house. Purchasing tile, plumbing fixtures, appliances and other finishes locally or nationally supports local businesses.

11. Over-insulate

So cheap and so effective. There are states in the United States that do not require any insulation. Insulation is so cheap; all you have to do is remember to over-insulate. However, no wall or ceiling is completely insulated. The framing studs interrupt the insulation envelope, allowing thermal transfer to bridge between the interior and the exterior. To break this thermal bridging, we installed environmentally friendly rigid insulation to the outside of the framing. This is an added upfront cost but more than pays itself back over time with energy savings.

12. Skip the paint

To improve indoor air quality and get rid of more manufactured materials, we use natural plaster finishes on the interior. This is actually cost-effective since it reduces the need for painting.

13. Add a light touch

We use LED fixtures exclusively since they use 80% less energy than incandescent bulbs, and last much longer. The use of LED lights is a revolution in home energy reduction. The variety of LED light fixtures has rapidly expanded, and they are infinitely more pleasing than fluorescent lighting.

14. Forget perfection

Thinking about and reducing the carbon footprint of the materials used in your house is easier than one thinks, and in many cases, more cost-effective. In our firm we don’t strive to be perfect or shame clients into doing more than they want or can afford. There is a reason why in Los Angeles there are only a handful of LEED or Passive House residences. LEED status comes at a price. You have to hire an outside LEED consultant that adds tens of thousands [of dollars] to the job. Most homeowners don’t want to spend the money for a label, and we feel if you can only get halfway toward being perfect that is better than nothing. Similarly, Passive House is a wonderful and admirable goal but is prescriptive, and if you don’t do everything, you don’t get the label. We strive not to be orthodox and reject clients just because they cannot achieve LEED platinum. We use the goals and techniques of LEED, Passive and other approaches to fit the budget and level of interest with our clients. Perfection is often unattainable. We offer solutions to our clients and help them go as far as they can.



{ 2 comments… read them below or add one }

Tessa September 16, 2021 at 2:21 pm

The design and materials of this granny flat appear to be well thought through. The bottom lines are – how much did it cost, and what’s the rent?


Paul Webb September 17, 2021 at 2:21 pm

Oh, Tessa! Love the snark. Of course, the cost and rent are unimportant, it’s the style and profit that matter.


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