ROCHESTER, Minn. — With milder winter weather returning to Minnesota last week, Ivan and Mary Idso woke up to a home comfy at 68 degrees Wednesday morning.
That’s to be expected for most people. However, most people probably didn’t cut their power from their utility company on Tuesday night — and keep it off through Friday morning.
Recent cold air and winter weather in Texas that left millions without power for days prompted Ivan Idso to test his home’s resilience if faced with a prolonged outage.
The Idsos installed rooftop solar panels on their home about four years ago. Ivan had never tested to see how well the home would perform relying only on solar energy for a few days in the winter.
"We’ve been wanting to do this for a while,” Ivan said. “But the events down in Texas made me want to test my preparedness if we had a similar event.”
A crippling ice storm isn’t out of the realm of possibilities — north or south.
“We’re pretty vulnerable against ice storms anywhere,” he said.
The Idsos’ home has eight breakers that can run entirely off the 4.7kW solar system. Those include the outlet that powers the home’s refrigerator, another outlet in the kitchen for the microwave and coffee maker, garage door, internet router and outlets and lights throughout the upstairs of the home.
The electric induction stove remained off. Although their laundry appliances include an efficient heat pump dryer and their water heater is also a low-energy heat pump, those remained offline as well.
“It’s a little inconvenient,” Ivan said. “But we’re still comfortable.”
The thermostat read 74 degrees after nearly 24 hours off the grid. The home features double-wall construction and passive solar heating design which accommodates the sun warming the interior during the day. Their home’s in-floor electric heat was also turned off in the experiment.
The reason these larger systems are off the solar-only breaker is because they draw down too much energy too quickly.
The Idsos test was to see if the home would maintain its comfort and remain habitable in the winter during a prolonged outage. Running off the batteries that stored the solar energy through the day, each morning of the test the couple found their batteries were still at 75% of charge.
During the day, the sun charges the batteries. Idso looked at the panel Wednesday afternoon. The panels were generating 1,700 watts of power while the house was drawing 1,300 watts.
Normally, that extra energy would go to the utility company and the couple would be compensated. Having temporarily disconnected from the grid, the extra energy was going to charge the batteries. Once the batteries are at 100%, the couple plug in space heaters to warm the house before the sun sets.
If we don’t use it, we lose it,” Ivan said of the extra electricity the panels generate once the batteries are full.
“I’m learning to manage these batteries,” he said.
Ivan said it’s important to test the resilience of your backup systems whatever they might be.
He tried to fire up his gas-powered generator as part of the test.
“I couldn’t get it started,” he said. “That’s why you test them.”
However, the couple’s electric car and its 60kWh battery could provide more than enough supplemental power should it be needed.
Overall, the home's temperature stayed in the mid-60s through the night and rebounded to the lower 70s by the evening through the test, which the couple concluded Friday morning.
“I’m convinced this is the right way to build a resilient home,” Ivan said of his solar and all-electric house.
That resilience will be needed, he added.
“We’re seeing more of these prolonged power outages,” he said. “And it’s mostly because of the weather.”