Building resiliency for power outages

Increasingly extreme weather events put your home's resiliency to the test; we dig into power outages in this post.

Increasingly extreme weather events put your home’s resiliency to the test; we dig into power outages in this post.

A passive house is uniquely positioned to withstand extremes in a changing climate. This article will help you to understand how much more resiliency will be built into your passive home as compared to a code built or any older home.

When the power goes out

In our most recent article on resiliency, we talked about protection against extreme heat. That thread is very relevant here. When extreme weather occurs, the outside temperature can make a difference.

If it’s extremely cold, how will your home stay warm? If it’s extremely hot, what about cooling?

But there are many other factors to consider when the power is cut, such as air quality, avoiding food spoilage, cooking, lights, etc.

Why build passive

A passive home will put you in a stronger position to weather a longer power outage as the home will stay close to a comfortable temperature for longer without external inputs, and the energy required to heat or cool your home will be much less than a home built to the codes of the past or even today.

The reason for this is that a passive home is built with passive solar gain in mind, for optimal cooling in summer and warmth in winter. The home’s orientation, including wall, window and roof and overhang elements all take into account the best decisions for natural cooling and heating.

Be sure to check out our related blog post Your EV as a Battery Backup.

Keeping the food in your fridge from spoiling is just one of many concerns when the power goes out for an extended period of time.

Net zero homes are resilient

Because of these factors, net metering a passive home of 1,500 to 2,500 square feet can easily be done with a small 6kW solar array, whereas a similarly sized home built to the current or recent code, would require a 40kW array or more. The cost difference involved is huge!

Many of the newer solar arrays have inverter technology that allow them to come with three additional plugs as standard, making it easy to slot in additional features. This is a great opportunity to connect a single 15kWh battery for power storage. This can be key in an outage.

Shown here is the solar array used for EkoBuilt’s model home — a 1,500 square foot bungalow and 676 square foot garage with office/studio. In the sunniest months, it often produces MORE energy than the home requires!

Our cost rule-of-thumb for backup battery storage is that it tends to run about $1,000 per kWh. A single 15kWh pack can run about $15,000. If you build this in from the start, it can be quite doable, but purchasing multiple battery packs isn’t an option most of us can enjoy. Planning ahead can make sure you use this power effectively.

Benefits of battery storage

When the power goes out, if your solar array has backup battery storage, you can be independent of the grid and keep your home operating (assuming your solar array hasn’t been damaged) for several days in sunnier periods, and 1.5 to 2 days during overcast, winter periods.

To generate power for a longer outage, such as the derecho that cut power for many home owners for a week in Eastern Ontario in 2022, one option is to pair a gas generator with a backup battery. Running a gas generator 24/7 is not only costly, it also creates pollution and noise, especially for those in the immediate vicinity.

Running the generator for 3 to 4 hours per day to charge your battery pack will then allow you to run your home for the remainder of the 24-hour period noise and pollution free. In this scenario, much less gas will be required, keeping you from joining lengthy line ups at local gas stations and beyond.

(It is worth noting that it’s also an option to invest in one of these batteries and to rely solely on charging it with a gas generator.)

Key takeaway: No power for a few days won’t be a big deal with a passive house if you don’t have backup, even though many of its systems are designed to run on electricity. With the way climate is trending, however, it’s a good idea to plan.

The Trillium passive house shown on an overcast day in summer.
Our first model passive home was built using the 3,000 sq ft Trillium floorplan. See all 50+ passive house plans.

The natural resiliency of passive

Several winters back, when we were operating our first model passive home, it weathered an extended period of extreme cold due to a polar vortex where temperatures dropped as cold as -40C / -40F.

We were actually away at the time, but a combination of remote monitoring and quick checks by family confirmed that on most days — with no heat input — the home hovered in the 18 to 19C range (64 – 66F), and on the very coldest days never dipped below 15C / 59.

Finally – if you’re looking for a small, super energy efficient, but also pretty powerful little space heater, the Senville 900W/1500W Tower Ceramic Heater with Remote, Digital Thermostat, Overheat Protection is excellent.

Plan your passive home and a resilient future

A passive home offers built-in resilience for storms and extremes. Ready to design yours? Check out our portfolio of 50+ passive house plans, or get in touch to discuss a custom design.

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