Bruce Saller, ADVANCE CONTRIBUTOR

My last article discussed the issues around increasing our electricity supply to lower imported electricity costs. The other option is to reduce our demand for electricity. Here are three ways to do it.

Heat Pump Hot Water Heaters

Electric hot water heaters use 18 percent of residential electricity. Since the average customer uses 12,000 kilowatt hours of electricity annually, that is 2,160 kilowatt hours. A heat pump hot water heater uses 75 percent less energy than a traditional resistive water heater, so you can save 1,620 kilowatt hours, or $291.60 a year by switching over. Dominion offers an instant rebate of $350 towards their purchase, lowering the price of a heat pump hot water heater to $1590. A similar resistive unit costs $673, so the owner would recover the additional cost in a little over three years.

Since Dominion customers are paying for the rebate, so how does this benefit them? Because Dominion needs to import some amount of electricity all the time, so any energy savings causes a reduction in imported electricity costs. The average cost of imported electricity is $.115 per kilowatt hour, so Dominion customers would save $186.3 annually and recover the $350 rebate cost in less than two years.

So, if you’re replacing your hot water heater, consider a heat pump unit. There are restrictions on where you can install it, so make sure you understand the space requirements before purchasing one.

More Energy-Efficient ACs

An air conditioner uses 19 percent of residential electricity (2,280 kilowatt hours). An air conditioner’s efficiency is measured by its Seasonal Energy Efficiency Rating 2 (SEER2). The higher the rating, the higher the efficiency. A unit with a SEER2 of 20 will use 20 percent less energy than a unit with a SEER2 of 16.

Unfortunately, Dominion does not offer rebates on other energy-saving appliances, so it takes longer to recover the cost difference. For example, I priced two air conditioners from the same manufacturer: the $2867 unit has a SEER2 of 13.4 and the $3123 unit has a SEER2 of 14.3. If you purchased the more expensive unit, your annual savings would be $26, so it would take ten years to recover your additional cost ($256). If Dominion had a rebate of $100 on the unit, both you and the Dominion ratepayers would recover their costs in six years.

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Attic Insulation

One way to reduce both your heat and air conditioning usage is to add attic insulation. The government now recommends we insulate our attics to R60. This recommended value has increased from R12 in the 1950s to R38 in 2006 to R49 in 2012 to R60 in 2021. So, if your house was built before 2021, you could benefit from adding insulation to your attic.

The amount of heat transferred through insulation is equal to the temperature difference divided by the R value. So, you lose five times as much heat with R12 insulation compared to R60 insulation. If you have a 1200-square-foot attic and increase the insulation from R24 to R60, it will cost you about $3000 and you will save about $300 annually. If Dominion had a $1000 rebate on the installation, both you and the Dominion ratepayers would recover the costs in less than seven years.

The actual payback periods for all of these energy-saving measures will be shorter since the price of electricity will continue to rise. The cost of imported energy this year will be at least 22 percent higher than last year, so our rates will go up again next summer to cover that cost. It makes sense for Dominion customers to subsidize a portion of customers’ energy-efficiency improvements since they also receive some savings. Contact your state representatives and tell them to expand the Dominion rebates to cover insulation and other appliances.

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Bruce Saller is a retired systems engineer with degrees in electrical engineering and computer science.

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