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

Solar Home

Simpson Family Residence
Nan, Walter, Jay and Skye Simpson
4 Meadowstream CT
Amherst, NY 14226
(716) 839-0062
enconser@buffalo.edu

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

 

SOLAR FEATURES

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 solar gain aperture approximately 200 square feet in heating season 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.
  • Glass type -- Triple glazed, double low-e coated, argon and krypton gas-filled “super-windows,” R-7.5 (center of glass) and R-6.7 (average).  Glass units facing SSE have a solar heat gain coefficient of 55% and thus are “tuned” for solar gain.  (2003)
  • "Solar fraction" is approximately 37% (sun provides approximately 37% of house heating requirements).  This performance is possible because house has been super-insulated and heating load is very low.
  • No thermal mass.  It’s not needed because house does not overheat and therefore have extra heat to store.  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)

  • 11.4 KW from three different PV arrays (2007, 2009, 2018).
  • Net-metered – National Grid supplies us power when we are not generating enough; we supply National Grid when we generate more than we use.
  • Annual electricity output is now greater than annual electrical consumption.  Annual excess sold at wholesale $ rates to the grid every April.
  • Cost of all three arrays, after NYSERDA incentives and state and federal tax credits, approximately $19,000 (13-year payback).

 

 

First array of solar paneling being installed.  Basement inverter converts DC current from the panels to AC for the house.

Solar Hot Water (2002)

  • Approx. cost $5,000; installed with volunteer help and assistance from local plumber; some parts used/recycled.   Provides over 50% 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!

clothes line

 

MINI-SPLITS AIR SOURCE HEAT PUMPS

  • Three high-performance air source heat pumps capable of high efficiency heating and cooling (2017).  Two serve upstairs and one serves the basement.
  • The larger upstairs unit, with a maximum heat output of 10,900 BTU/hr @ 47 degrees outside air temperature and 6,700 BTU/hr @ 17 degrees, can heat the entire upstairs of our house. 
  • Coefficient of Performance (COP) for 47 and 17 degrees outside air temperature, respectively, is 3.27 – 4.50.

 

ENERGY CONSERVATION AND EFFICIENCY MEASURES

Heating Conservation/Heating Load Reduction

  • Super-Insulated Retrofit (1991) inspired by the Super-Insulation Retrofit book produced 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 significantly reduced (and in places eliminated) thermal bridging.  Contractor and self-installed.  Cost: $15,000+ and 25-year payback.

 

  • Previously mentioned super windows (2003) which are highly efficient in keeping the heat inside with an R-value of 7.5 yet tuned for solar gain on the south side.
  • Draft reduction –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, though 55 is never reached because the house loses temperature very slowly.  (Each degree of setback over 24 hours saves approx. 3%.) 
  • Lower indoor temperatures are comfortable in our house because of radiant heat from sunlight, warmer wall temperatures due to super-insulation, and near zero drafts.

Cooling Conservation

  • While the mini-splits can be used for upstairs cooling, their use for that purpose is minimized by open windows, cross ventilation, overhangs, awning, white roof, and use of ceiling fans and portable fans.

Energy Monitoring and Real-Time Feedback

  • The Energy Detective (theenergydetective.com), with read-out placed in kitchen, provides real-time electric power wattage (use).  Seeing how much electricity you are using at any given time encourages energy conservation.

Appliances and Lighting

  • Only one refrigerator/freezer and most efficient model available – 100% more efficient than older model replaced.
  • Minimize use of gas dryer by using a clothesline in summer and winter.
  • LED or Fluorescent lighting in all rooms. Converting to all LED.
  • Additional light switches installed in basement to provide lighting zones (allowing use of parts of the basement without turning all lights on).

Transportation

  • Three gasoline-powered vehicles. No electric car yet.
  • Primary vehicle is a Toyota Prius C, which achieves over 50 mpg in the summer (sometimes as high as 75mpg for short trips) and 40 mpg in winter. It’s been driven an average of only 6,000 miles a year.

 

OTHER LIFESTYLE MEASURES

  • 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, when possible we buy products that 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.