Residential Energy Savings with Michael Blasnik: Higher Priorities
On Thursday I went to a lecture by energy consultant Michael Blasnik at MIT. Blasnik’s right up my alley, a very practical environmentalist who bases his recommendations on studies of the real efficiency of energy-saving activities. He’s currently conducting a study of the national weatherization assistance program. So his presentation was full of something I’ve been after for a long time: hard numbers comparing the efficiency of different actions. There were so many I’m going to have to break it up into two posts.
Blasnik emphasized that low-income weatherization programs should focus on the highest energy users. It takes more money to bring their houses up to speed, but it will save more energy per dollar spent. (The best energy savings also occur in locations where it snows most of the year.) A 20–30% improvement is considered a good average.
Some surprising things I learned:
- Ten percent of households leave their furnace fan on constantly, which wastes them $600 to $800 a year. Isn’t this crazy?
- Second refrigerators and freezers waste a lot of money—$100 to $400 a year. I doubt people save $400 a year by buying in bulk and freezing it.
- Shortening showers by 4 minutes per day only saves $20 to $40 a year.
- Switching half your laundry to clotheslines only saves $15 to $40 a year. In winter it saves even less energy because the evaporation cools off the house and adds to your heat load.
- Switch furnace fan from “on” to “auto” – costs $0 – saves $600–800/yr
- Insulate empty attic (bypass seal, 1000 ft^2) – costs $1,000 – saves $400/yr
- Insulate empty walls (dense pack, 1000 ft^2) – costs $1,200 – saves $350/yr
- Replace old furnace w/less than 92% efficiency (gas, if heat >1200 th) – costs $3,200 – saves $450+/yr
- Get rid of second fridge – costs $0 – saves $125–400/yr
- Get rid of standalone freezer – costs $0 – saves $100–250/yr
- Turn off TV when not in use (vs. on 24 hrs/day) – costs $0 – saves $100–200/yr
- Turn off stereo when not in use (vs. on 24 hrs/day) – costs $0 – saves $80–160/yr
- Set back heat 8 degrees, 8 hours per day – costs $0 – saves $75–140/yr
- Replace 15 bulbs w/CFLs – costs $60 – saves $75–150/yr
- Lowering thermostat 2 degrees (24 hrs/day) – saves $60-$100/yr
- Turn computer off (vs. screen saver) – costs $0 – saves $40–120/yr
- Insulate attic w/existing insulation (bypass seal) – costs $800 – saves $125/yr
- Motion detectors on outdoor lights – costs $50 – saves $40–150/yr
- Fix hot water leak – costs $5–150 – saves $50–200/yr
- Replace old (pre-’93) fridge – costs $500+ – saves $75–200/yr
- Fans/drapes/etc. instead of AC – costs $0 – saves $20–200/yr
- Showers reduced by 4 minutes/day – costs $0 – saves $20–40/yr
- Replace top load clothes washer (1 load/day, hot water) – costs $500+ – saves $65–175/yr
- Clothesline (½ of loads, 2x savings if electric dryer) – costs $0 – saves $15–40/yr
- Cold wash laundry (½ of hot loads to warm/cold) – costs $0 – saves $10–40/yr
- Power strip: computer – costs $0 – saves $10–40/yr
- Very low flow showerhead (<1.8 gpm) – costs $25 – saves $10–40/yr
- Air seal using blower door – costs $700 – saves $75–250/yr
- Power strip: TV – saves $5–50/yr
- Turn off fans when room is empty – costs $0 – saves $5–20/yr