When combined with a substantial solar system, if you have enough Powerwalls, you could go off-grid and be energy independent. But remember, you'd need enough Powerwalls to power your whole home continuously because a single Powerwall can’t power large appliances for extended periods. One Powerwall is able to power an average-sized home's emergency circuits, lights, and outlets. To power large appliances, you likely need two or three Powerwalls.

While many states require all new construction to undergo blower door tests, it’s not a requirement for existing homes. But in both cases, a blower test helps confirm that the contractor has sealed the exterior, that the type of ductwork installed is functioning properly, and that your home is as efficient as possible.

Motion-sensor lights use one watt while on standby and five watts while turned on. They’re usually on for one hour over a 24-hour period, bringing the total wattage to about 28 watts per day. LED lights use around 6.5 to 8 watts while on. If you leave an LED light on all night, with night ranging from 10 to 14 hours, you’re looking at using 65 to 112 watts a night. You can minimally cut your wattage in half by switching to a motion-sensor light.

Dryers are designed to use as little electricity as possible, but power is still required to run the motor that turns the drum and to heat an element that pumps hot air. Eco devices are available and may lead to cost savings in the long term, but you should run the figures before committing to an eco-friendly device as they are often much more expensive to purchase.