Touch here for mobile friendly version

Monday, March 9, 2009

Weatherization Nation--How I reduced my natural gas use 60 percent for less than $400

Update 10/16/2009: Solar hot water project started.

Update 1/23/2010: 95 percent efficient furnace installed.

My name is not Earl. I've crossed everything off my list and I'd like to share what I have learned.

I'll start with my results to date. I spent roughly $400 and achieved a 60% reduction in my gas-heating bill for the month of February. My goal is an 80% reduction but that last 20% will cost me. To obtain that I will install a solar hot water panel in the one sunny patch of yard I have, along with a heat exchanger on the first floor shower drain, and possibly one of these bad boys. Our hot water accounts for almost 20% of our gas use.

And here's my list:

  1. Reroute gas furnace air-intake ducts to draw warm air from heated space rather than basement.
  2. Install R-21 insulation in unheated basement ceiling (which is the floor of the first story).
  3. Design and build moveable pop-in insulated shutters for all first floor windows.
  4. Keep upstairs doors to bedrooms and bath closed during day.
  5. Install R-11 in stairwell wall that leads from unheated basement.
  6. Weather-strip door from basement to house
  7. Install insulated door on laundry chute.
  8. Install damper in fireplace.

We maintain the first floor of the house (where the thermostat is located) at 70 degrees during the day (when occupied) and at 60 degrees during the night or when unoccupied. The heat loss from the first floor keeps the upstairs warmer than 60 degrees. As you walk from the balcony to the second floor, to the first floor, and on into the basement you can feel the air get colder and colder because warm air stratifies (hot air rises).

Use encapsulated fiberglass insulation battens. The fiberglass is enclosed and won't get under your shirt and make you itch "like a man on a fuzzy tree." It is usually white and reflects light well. It costs more but is not the fire hazard that paper-backed insulation can be. Building codes require that you cover paper-backed and foam board wall insulation with a 15-minute fire barrier (typically gypsum board or metal) to give occupants time to escape a fire before the smoke and fumes are released.

The most effective item on the list by far is the pop-in moveable insulation. In theory, these things cut the heat loss through our walls almost in half. We have a lot of big windows. You should be thinking, "What in the hell is pop-in moveable insulation?" It's a piece of insulation cut to the shape of your window and covered in cloth that you can "pop" into the window cavity from the inside. Get it?

How to make your own moveable insulation

  1. Use two-inch thick polyisocyanurate insulation board with aluminum foil on one side.
  2. Use a cheap sabre saw to cut the foam about a quarter of an inch smaller than the opening you plan to cover.
  3. Cover the edges with God's gift to man (duct tape) to keep them from chipping.
  4. Use sticky-backed foam insulation strips to fill gaps around the edges. It does not have to be perfect.
  5. Sew or have someone sew a cover out of fire resistant fabric. Be sure to add a few tabs to make handling easier.
  6. Install it with the foil toward the inside of the house leaving a gap between the foam and the glass.
Make one for a single window to get up the learning curve before you move on to another window. Get all of your screw-ups out of the way on your first window so you don't screw up all of your windows. Each window will be different and will require a different design.
Watch for signs of excess moisture against the wood sill. My windows stay dry but if yours don't, you can protect the wood with a few extra coats of oil-based paint or a good sealant. Tile or slate also works if you have nothing better to do.

Back in the 70s' when America was first introduced to the concept of energy conservation, insulated window shades were all the rage. They are a form of moveable insulation, sometimes referred to as night insulation. They could boost your window up to around R-4 or 5. The ones I made take the windows to around R-12.

I was granted permission for this experiment from my family under the condition that the insulation does not go up until after dark and is out before my wife gets out of bed. For all of you wannabe handymen out there, always remember, "Ain't mama happy, ain't nobody happy," and "If the women don't find you handsome, may they at least find you handy."

Keep in mind while designing these, what you will do with them when they are not in the window. They can fold accordion style and lay behind a couch. They can be covered with art and hang on the wall in plain sight, even on top of each other for a 3-D look. If you have a friend artist, turn her loose on them. They can be beautiful, high-status works of art--conversation pieces at dinner parties.

Every house is different. The highest priority and the biggest bang for your buck is to insulate your attic or roof. The best insulation is fiberglass and the more, the better. Be careful not to block airflow from the eve vents. I already have R-36 in mine.

The easiest to insulate, but the lowest return on investment is your floor. It will have the lowest temperature differential. May as well do it because it is relatively easy, unless you have an old house with 6 x 6 beams spaced four feet apart…

Replacing your old single pane windows with modern double-glazed ones will cost a fortune and improve each window from an R-1 to about an R-2 to R-4.

You can check to see if your walls have insulation in them by removing a piece of baseboard trim and looking for it by chipping a small hole in the plasterboard. You can have professionals (and I use that word lightly) blow insulation into the walls by cutting six inch holes along the top of the walls. The insulation will get hung up on wires and fire blocking and also settle with time leaving the top without insulation and the bottom compressed. There will also be the potential for moisture problems. There are other things you can do short of ripping down the plasterboard but there is no easy way out with walls. Mine are R-11. I ripped down the lath and plaster to do it many years ago.

The very cheapest thing to do is look for holes and cracks to plug, especially if you don't have a fireplace damper. A chimney without a damper is worse than having an open window because it will cause a draft that will suck air out of your house.

Hopefully, by this time next year I will be able to report that my family has reduced its total energy use by 80% without sacrifice or undue expense. By swapping a 24 mpg Outback for a 48 mpg Prius and a 15 mpg Cherokee for a hybrid electric bike we have already managed to reduce our car footprint roughly 80%. We still travel the same number of miles without sacrificing time, comfort, or cash.

I have proved (mostly to myself) that a 100% solar powered home is not just another Internet urban legend when I designed the Hybrid Solar Home for the Pacific Northwest that would use solar energy for all of its needs, power and heat (at least on paper). Great if you're in the market for a custom designed home with unobstructed southern exposure but the big ticket item is going to be retrofits of existing structures.

Next up, reduce the electric bill. The two big-ticket items will be the refrigerator and dryer. This is going to be interesting.

Click here to see a list of my articles and to subscribe to future posts.


  1. This is my first post using this platform. Any feedback on how to improve the functionality would be much appreciated.

  2. Anonymous12:13 PM

    Old houses are so hard to make efficient, sounds like you are doing everything you can though, with the heat exchange and the planned solar panel for the hot water.

    Your link to the site does not work.

  3. Anonymous12:20 PM

    Also, though a waste water heat exchange is a bit pricey, this is the type of investment in an appliance that by design is low to no maintenance, and this particular appliance does not wear out.

    Not a bad investment when you consider living in a house for 10 years plus.

    The only thing I can think of that you might want to do to improve efficiency further would be to insulate all the hot water pipes that you can get at.

  4. Good advice folks,

    Fixed the broken link. It goes to a heat pump hot water heater not quite on the market yet:

  5. This is quite a list of achievements. I am not a handy person, but I would really like to start making my little house more efficient.

    BTW I found your blog via comments you posted over at gristmill. I was searching David Quammen on Google, and my first good result was an interview with him. Appended to the (2006) interview is an extensive comments section. The comments evolved (npi) into a debate, and you were one of the participants. In any case, I was impressed enough with your arguments and your writing to chase down your blog. Keep up the good work.


  6. Thanks, Ken

    Nice blog. Gristmill has been suffering technical difficulties lately so I created this blog where people could comment.

  7. Just got our March gas bill. It was higher than last year. I was perplexed. Although it had two more heating days and the average temperature was 3 degrees colder, it should have been much lower.

    I used that information to ratio last year's bill and came up with the same number as the gas company.

    That's when I realized this bill must be an estimate based on last year's bill. Sure enough, poking around on the bill I found the code for estimated. Won't know the real deal until they take a real reading next month.

  8. Some more tips culled from Romm's post on Grist Magazine:

    1) Insulate and turn down your hot water heater. It only takes 123 degrees needed to kill Legionnaires Disease. You can save up to 10 percent off your water heating bill.

    (This would equate to about 1.5% off my gas bill, not sure it's worth it.)

    2) Insulate your hot and cold water pipes, especially the first 10 feet from the water heater. You'll get a 5 percent savings off your hot water bill.

    (Half a percent off my gas bill)

    3) Replace your thermostat with a programmable model. Look for EnergyStar pre-programmed model. Save $180 a year off your heating bill.

    (This would only help if you tend to ignore your thermostat. It might actually increase our gas use)

    4) Seal your ducts with mastic. Most homes average 30 percent duct leakage. $300 a year in potential savings.

    (Will do this for sure and will be very happy if it results in a 30% improvement)

    Caulk and seal around your windows and exterior doors. Most homes average a 20 percent air leakage.

    (My house was much worse than average)

    5) Replace leaky single paned windows with low-e, double glazed ones.

    (Very expensive option. Can also just caulk and use moveable insulation for more bang for your buck)

    The rest of the suggestions pertain to electricity and homes in climates that need air conditioning, not a concern in Seattle. Also keep in mind that if your water heater, ducting and furnace are located inside your insulated envelope you don't need to do any of these things because the waste heat will all go toward heating your house. My furnace and hot water heater are in an unheated basement outside of the home insulaton envelope.

  9. Another tip for insulating your floor if the joist spacing is something other than 16 or 24 inches. Use unfaced fiberglass insulation and Tyvek sheeting. Staple on the sheeting leaving one end open and stuff it with insulation. Worked well for me.

  10. Anonymous9:46 AM

    When you replace the hot water heater, put a heat trap in the hot-water-out side to cut gravity losses (hot water rises just like hot air).

  11. Anonymous3:08 AM

    Instead of putting insulation under your floor, you could put it on top. One house that I lived in had a tiled floor - great in summer for keeping cool, horrible in winter. We used a removable carpet piece to fit (cheap design), and then added extra rugs (very nice) on top. We could even walk over it in bare feet in winter! You will need a storage place for the 'insulation' in summer though - perhaps the floor in another room!

    All the best

    Nick Ayres


Comments that are not respectful of other participants will be deleted, so don't waste your time on a post that will be canned. Feel free to post links to pertinent sources and to your own website as part of your comment. Spam disguised as a comment will also be deleted as will comments that consist primarily of copied and pasted words from other authors (plagiarized content).