Owners of a decades-old manufactured home push the envelope on energy efficiency, cutting their home’s electricity use by more than 70% with cost-effective upgrades.
When Glenda Alm and Dick Kent decided to put down roots after four years of traveling, they bought a 30-year-old manufactured home in a mobile home park overlooking Padilla Bay in Bayview, Washington. It got them back to their Northwest roots, and gave them a home with a great view.
But the poorly insulated, leaky home was heated with a 30-year-old electric furnace, and the previous occupant had used an average of 45 kilowatt-hours (kWh) of electricity per day. Their first task was to identify and replace any energy wasters to reduce their household consumption and electricity bill.
Glenda and Dick were no strangers to tackling energy efficiency and living on an energy budget. They had both lived with off-grid PV systems, and four 100-watt PV modules had kept the batteries in their RV topped off while they were traveling and without shore power.
The home they bought had advantages over the neighboring mobile homes because it already had better wall insulation and windows. For starters, Dick cleaned and sealed the ducts, and added tight rodent-proof skirting all around the home.
The previous owners had upgraded the kitchen appliances about seven years before Dick and Glenda purchased the home, so they were not the worst energy hogs. They replaced the clothes washer with a new Whirlpool HE model using a utility incentive program. They still prefer solar clothes drying, and seldom use the 20-year-old electric dryer. They replaced the 20-year-old refrigerator with a new and smaller (15 cubic feet) model that uses about 400 kWh per year.
Lighting was an obvious early target—the existing lighting was 25 bulbs totaling 2,000 W. Today, 15 LED bulbs and three CFLs—a total of 320 watts—result in nearly the same lumens, and some task lighting has improved the functionality. The local utility offered LED bulbs at a deep discount, which also helped fund the improvement.
Dick removed a big and wasteful 36-inch CRT TV (300 W), and replaced it with a smaller, efficient, LCD model (100 W). Dick and Glenda only use it about 10 hours a week—which translates into about 50 kWh per year.
Next, Dick ferreted out the phantom loads that were using energy continuously—such as the entertainment center and pellet stove remote—while giving no benefit in return. Plug strips were a key part of curbing these loads, making it easy to turn off related loads with the same switch. At 30 W, the pellet heater’s remote control receiver was a “large” phantom load at 263 kWh per year. Put on a plug strip, the heater is now a negligible load.
These few, easy changes, with little investment, reduced energy use by 13 kWh per day—from 45 kWh to 32 kWh. Next, they tackled the heating system. The forced-air electric furnace was a prime candidate for an energy upgrade. The Wesco furnace was 30 years old and most likely contributed to nearly 50% of the energy cost with 20-plus kWh per day. It was removed, and the vents all sealed permanently to eliminate energy losses. At the same time, the floor was reinsulated with R-16 fiberglass batts between the 2-by-6 floor joists.
Dick replaced the furnace with a ductless minisplit air-source heat pump purchased online for $1,500. He and a friend installed it in a few hours, but hired a local HVAC company to check for leaks and charge the system with refrigerant. With a $1,200 rebate from the local utility, the upgrade cost less than $500. The old 4 kW electric furnace used about 24 kWh per day, while the new 1.2 kW heat pump averages less than 5 kWh per day.
While working on the heating system, Dick also dealt with the old plumbing in the home. He remodeled both bathrooms, installing PEX plumbing with no fittings under the floor. He discarded the 20-year-old electric tank water heater and installed a Rheem 13 kW tankless electric water heater ($200). While the electricity draw of the on-demand heater is high, there are no standby losses as with a tank-style heater, reducing water-heating energy use by about 75%. Short plumbing runs also curb energy losses and wait time for hot water in both bathrooms and the kitchen. Dick used a manifold system—each appliance is served by a home run with no plumbing fittings under the floor (direct connection) and not a series connection from one use to the next.
The space- and water-heating efficiency upgrades reduced the household electricity use by another 20 kWh, bringing it down to about 12 kWh per day. At $0.106 per kWh, Dick and Glenda now pay about $60 per month for electricity in the winter (and buy 100% green energy from the local utility). Many of their neighbors living in all-electric homes in the park pay $300 a month for electricity in the winter.
With a couple of decades in the RE industry, it’s no surprise that Dick has already installed a few PV modules—four 100-watt modules on his off-grid workshop keep a small battery bank charged to run his power tools. They are the same style of module he had on his RV and that he sold to RV clients. But Dick has bigger plans, and is considering a 2 kW batteryless grid-tied PV system, which would get their house about halfway to net-zero energy use.