Walter Comic

“The cleanest and least expensive kilowatt hour or BTU is the one you don’t use.”

Solar Home

Simpson Family Residence
Amherst, NY 14226

Maximizing Energy Conservation, Efficiency, and Renewable Energy  Striving for a Climate Neutral Lifestyle


Passive Solar Space Heating and Daylighting
  • "Accidental" passive solar design.   There are about 40 houses in our neighborhood of similar design with large window walls.  By accident of street layout and orientation of houses on lots, only 5 or 6 of these houses have their windows facing in the right direction, i.e. south.  Luckily, ours was one of these.


  • Orientation -- South-South-East (SSE) -- 30 degrees east of "solar south."  Insolation penalty for SSE orientation -- approximately 14%.
  • 240 square feet of SSE window glass; effective aperture approximately 200 square feet (due to large overhang which blocks some sun even in winter).  If we de-rate by 14% to allow for SSE orientation, our 200 square feet of SSE-facing windows are equal to 172 square feet south-facing glass.
  • SSE glass type -- Triple glazed, double low-e coated, argon gas-filled “super-windows” (2003), R-7.5 (center of glass).  Units facing south have a solar heat gain coefficient of 55% and thus are “tuned” for solar gain. 
  • "Solar fraction" is approximately 40% (sun provides approximately 40% of house heating requirements).  This performance is possible because house has been super-insulated and heating load is very low.
  • No thermal mass (not needed; house does not overheat).  General rule is if south-facing window area is over 12% of floor space, thermal mass is needed.  We are at 9.3%, assuming south-facing equivalent of 172 square feet of glass (see above).
  • Summer sun control -- overhang and awning.
  • Daylighting -- during daylight hours sunlight adequately illuminates most rooms without the need for electric lighting.


Photovoltaic Solar Electric System (2007 & 2009)
  • 4.0 KW solar capacity; approx 3.2 KW maximum output
  • Net-metered – National Grid supplies us power when we are not generating enough; we supply National Grid when we generate more than we use.
  • Sized to meet 100%+ of our electric needs
  • Cost: $27,000.  After NYSERDA incentives and federal and state tax credits = $9,000 cost to us.  15+ year simple payback.



Solar Hot Water (2001)
  • Approx. cost $5,000; installed with volunteer help and assistance from local plumber; some parts used/recycled.   Provides 65% of our hot water needs.


  • Three season system – really no production November - January.  Note snow cover on the week we had seven feet of snow.
  • Active, indirect system with two 4X8 U.S. Solar Corporation AF-32 collectors, glycol/water loop to prevent winter freeze-ups, heat transferred to second loop via heat exchanger, tow 50 watt pumps, 120 gallon storage tank


Solar Clothes Drying
  • Yes, we use a clothes line!

cloths line


When our PV system does not supply all of our electricity, we buy 100% "New Wind Energy" from Community Energy at: or call 1-866-WIND-123.  This option costs 2.5 cents per kilowatt hour.  It will add a few dollars to your electric bill -- a small price to pay to quit the coal and nuclear habit and to promote clean new wind power development in New York State.


Energy Monitoring and Real-Time Feedback

The Energy Detective (, provides real-time wattage and daily, monthly, etc. kilowatt hours data.  $140

Alternative product: Energy Cost Monitor by Blueline, (  $135.

  • Super-Insulated Retrofit (1991) inspired by the Super-Insulation Retrofit book -- R-30 walls, R-45 and R-50 ceilings, and R-18 basement walls.  Use of high density fiberglass insulation (R-15 for 3.5 inches vs. R-11) and expanded polystyrene foam.  Retrofit design minimizes or eliminates thermal bridging.  Contractor and self-installed.  Cost: $15,000+

  • Insulation around chimney with high temperature ROXUL AFB (2,150 degree F) non-combustible mineral wool batts, eliminating thermal hole and losses around chimney.


  • New super windows (2003) with center of glass R-value of 7.5, tuned for solar gain on the south side (see passive solar section for more detail on all windows).
  • Draft-free, tight but not-too-tight, envelope (0.33 air changes per hour as per blower door test). 
  • 95% efficient natural gas furnace.
  • Automatic set-back thermostat -- winter settings are 63 degrees during day; 55 degrees at night.  (Each degree of setback over 24 hours saves approx. 3%.) 
  • Lower space temperatures are comfortable in our house because of radiant heat from sunlight, warmer wall temperatures due to super-insulation, and zero drafts.

  • Insulation around chimney with high temperature ROXUL AFB (2,150 degree F) non-combustible mineral wool batts, eliminating thermal hole and losses around chimney.

chimney holeJeff Brennan and Mike from Blackrock Roofing open area around chimney
LEFT: Thermal hole and chimney around chimney exposed    RIGHT: Jeff Brennan and Mike from Blackrock Roofing open area around chimney

Summer Cooling
  • Open windows, cross ventilation, overhangs, awning, white roof, and use of ceiling fans and portable fans instead of air conditioning.
Hot Water
  • Solar hot water system substantially reduces natural gas water heating load.
  • Insulating blankets on natural gas water heater.
  • Adjustable flow shower head (we use lower flow in winter when solar hot water system isn’t producing "free" hot water).
  • Horizontal axis Energy Star clothes washer.  Usually wash warm; rinse cold.  Cold wash, cold rinse uses no hot water.
  • Always use "water miser" feature when operating dishwasher.
  • Leave warm water in bath tub until it cools in order to help heat and humidify house in the winter.
  • Only one refrigerator/freezer  and most efficient model available – 100% more efficient than older model just replaced.
  • Additional switch on microwave to eliminate "phantom watts" – but still have 70 watts of power consumption when everything is “off” – need to track down!
  • Computer energy saving "sleep modes" enabled, and computers switched off when not in use.
  • Dishwasher operated with "water miser" and "no heat dry" settings.
  • Horizontal Axis Energy Star clothes washer. 
  • Minimize use of gas dryer by using a clothesline in summer and winter.
Electric Lighting
  • Fluorescent lighting in all rooms -- including 13 compact fluorescent lamps in table and hanging lamps.
  • Conventional chandelier with 375 watts of incandescent bulbs replaced with Tiffany lamp with 45 watts of compact fluorescent lighting (which produces more light).  One, two, or three 15 watt compact lamps can be used at a time.  Minimum of 88% savings over incandescents.

Economics of Compact Fluorescent Lamps

Compact fluorescent lamps last 10,000 hours and produce four times as much light per watt as do incandescent bulbs which last only 750 hours.  Thus, an 18 watt compact fluorescent lamp will produce as much light as a 75 watt incandescent and it will last 13 times as long. 

Lamp costs are less over 10,000 hours of operation, i.e. one compact lamp vs. 13 incandescents. 

What about energy cost savings?  Here is a comparison, assuming electricity costs 11 cents per kilowatt hour (typical National Grid residential rate, not counting customer charge):

18 watt compact fluorescent
0.018 kw X 10,000 hrs X $0.11 per kwh = $19.80 for 10,000 hours of operation

75 watt incandescent
0.075 kw X 10,000 hrs X $0.11 per kwh = $82.50 for 10,000 hours operation

Thus, you will save $62.70 for every compact fluorescent lamp you install over the lifespan of the lamp.  Not bad for a $3 lamp!

  • Removal (delamping) of unneeded fixtures.
  • Additional light switches installed in basement to provide lighting zones (allowing use of basement without turning all lights on).
  • Low flow toilet with Sloan "Flushmate" valve which uses water pressure to compress air in a pressurized tank.  The compressed air assists flushing, producing very effective flushing in a 1.6 gallons per flush toilet.  (No double flushes necessary!)
  • Don't water lawn (allow grass to go dormant in summer).
  • Relatively high mileage smaller cars -- 42 and 50 mpg (highway driving), the former a 2001 Toyota Echo and the latter a new Prius C which gets over 60 mpg around town in warm weather.

Gas saving vehicle

  • Drive each car average of 5,000 miles a year (much less than national average but still too much).

  • Retirement has led to the purchase of a relatively small modified van RV which is both an embarrassment and a joy.  Gas mileage is a closely guarded secret but at least we drive it much less than its previous owners and carry our bikes on the back.  When parked in the driveway it is sequestering an incredible amount carbon!  (Or so we like to think.)


  • Simpson’s vegetarian diet saves energy and reduces greenhouse gas emissions because meat production is energy (fossil fuel) intensive.  Ten pounds of grain must be produced and fed to a cow to produce one pound of meat.  All that takes energy and other resources as well as produces air and water pollution When we eat the grain directly, we can eliminate all that inefficiency and waste –as well as cruelty. Cows are also responsible for release of methane, another greenhouse gas.
  • Besides recycling, the Simpsons buy products which are made of recycled material, e.g. printer paper, paper towels, toilet paper, napkins, and tissue paper.  Recycling saves energy and buying products made of recycled materials “closes the loop” by creating a market for recyclables.


To mitigate carbon dioxide emissions associated with our home and use of our cars, we have taken the following steps:
1. Purchase of wind power to meet 100% of home electrical needs not supplied by our PV panels.

2. Purchase of an additional 15 tons of CO2 emissions reduction from NativeEnergy,  Cost: $150.  Do annually.  NativeEnergy achieves emissions reductions by purchasing “green tags” associated with the development of new wind turbines or farm methane generation. 


We calculated that we need 3 tons of carbon dioxide offsets to cover the operation of our van and we allowed for an additional 12 tons of mitigation to offset home natural gas use (heating, hot water, cooking, etc.), gasoline for our two cars, and other consumptive activities. 
The 12 tons is calculated as follows:

Natural gas consumption: est. 400 CCF/year X 12.1 lbs of CO2/CCF = 4,840 lbs of CO2
Gasoline consumption: 10,000 miles/year (total both cars) @ 40 mpg (recognizing that our “42 and 50 mpg cars” get lower mileage on an annual basis due to warm up, winter driving, etc.) = 250 gallons/yr X 23.8 lbs of CO2/gallon = 5,950 lbs of CO2

4,840 + 5,950 lbs = 10,790 lbs of CO2 or 5.4 tons

We rounded that off to 12 tons in order to begin mitigating energy and CO2 impacts associated with occasional air travel, material goods purchases, and other energy-related consumptive activities.

3. In 2011 we had our driveway replaced.  After considering greener options (and rejecting them because of potential problems associated with permeable driveways in colder climate and our inability to find experienced installers) we went with a conventional concrete drive.  We purchased 15 tons of CO2 offsets to cover the emissions involved with making the cement and laying the drive way.

Click here for calculation showing 7.09 tons of CO2 were released in manufacturing the concrete used in our driveway.  We rounded up to 15 tons to at least partially allow for the other materials and installation.