Like solar panels, technology continues to improve in equipment that either consumes electricity, saves electricity, or switches you over to electricity. Typically, a solar electric system is designed based on the last 12 months of electricity consumption. In reality, we want that design to reflect the average consumption expected over the future 30-year life of the solar system. And that is going to be significantly impacted by the equipment you might choose in the future.
If your air conditioners (AC) are on their last legs, your fridge is twenty years old, or the pool pump is not variable speed, then time to consider what consumption would look like after all of these have been replaced and before designing your solar system.
AC is usually the largest consumer of electricity. A typical AC unit’s life is 15 – 30 years, and over this period the efficiency of the existing unit will drop. A new unit will have improved significantly, yielding a 30 – 70% drop in electricity required, depending on the model selected. SEER is the rating used to the measure efficiency of an air conditioner. Twenty-five years ago, a 12 SEER model was considered high efficiency, and now it would be difficult to find a basic model with a SEER less than 14.
Dual speed and variable speed air conditioners start at around 16 SEER and go as high as 26 SEER. Ductless mini-split air conditioners have ratings as high as 30+ SEER. Thinking in terms of array size, a home using 20,000 kWh per year of electricity could see a 7,000 kWh per year savings going from an old AC unit to a 20+ SEER, This would reduce the solar system from 12 kW to 8.4 kW, a saving after tax credits of ~$7,500. Always a good idea to compare investments.
ENERGY STAR certified products, which include specific brands and models of air conditioners, meet strict energy-efficiency specifications set by the U.S. EPA.
For pool homes, the second-largest consumer of electricity can be a single-speed pool pump which may be responsible for 20% of your utility bill. By switching to an intelligent variable speed pump that optimizes circulation rates during off-peak times the savings can average 70%. Again, look for the ENERGY STAR certification.
Other certified appliances to consider, now or in the future, are your clothes washer, dishwasher, refrigerator, freezer, ceiling fans and light bulbs. The cleanest non-renewable fuel is natural gas and further savings can be achieved by choosing a natural gas dryer, range, cooktop or water heater over electric.
And don’t forget about your electronics, as ENERGY STAR certification applies to computers, monitors, televisions, stereos, printers and copiers as well. An older home with single-pane windows should have those replaced with double or triple pane windows. Tinted film, reflective surfaces, or inert gas-filled space between panes reduce heat gain through windows. ENERGY STAR certifies windows, doors and skylights as well.
Not only will all these improvements save electricity consumption, but also possibly allow a new AC unit to be downsized, saving on the initial cost.
Offsetting these very real future savings are very real future increases in consumption when one, two, three or more electric vehicles (EV) need to be charged! Yes, even EV chargers have ENERGY STAR certification.
Consideration of all of these possibilities now will result in a better decision when it is time to install solar.