Renewable Energy & Sustainable Design in Buildings Awards

2012 RESIDENTIAL AWARDS
New Construction  |  Pioneer  |  Renovation  |  Commercial/Institutional Awards

Summary Description:
This 2,800 sf 4-bedroom home in North Boulder built in 1991 features a 4 kW photovoltaic system and a domestic water heating system that contributes to 80% of the water heating load and many smart energy efficiency features. This project is a great example of how to integrate sustainability features and how cost-effective energy conservation can be.

Address:
840 Quince Avenue
Boulder, Colorado
Pieter & Martha van der Mersch
vdMersch@comcast.net

1. Renewable Energy Features:

1. Passive solar heating
2. Excellent daylighting on all sides. Borrowed daylight to interior corridors.
3. Solar domestic-water heating – Installed when house was built.
   Per f-Chart, solar contribution was determined to be 80%.
4. Solar-electric system (4 kW) – Installed in 2006.

2. Environmental Impact:

1. High-efficiency condensing furnace with 7-day programmable thermostat with 4-settings per day.
2. Based on actual consumption, we estimate the natural-gas consumption is approx. 20% of what a regular house this size would use in Boulder. Interestingly, on sunny winter days, the furnace will not go on regardless how cold it is. Per utility summary for 2011-2012, consumption for the year was 118 Therms for 5,278 Heating Degree-Days. This gives us 2,060 Btu/Degree-Day, and for 2,800 Sq. Ft.: 0.74 Btu/Sq. Ft.-DD.
   This gas consumption includes back-up domestic water heating and gas clothes dryer.
3. Adding the solar-electric system reduced our utility consumption by ~70%, determined by comparing yearly data taken from the utility’s watt-hour meter and the solar-electric monitor. Per 2011-12 utility summary presented below, total consumption for the year was 3,140 kWh (1.12 kWh/Sq. Ft.- Yr.) which peaks in the winter because our elderly father needs to operate an electric heater in his bedroom to maintain ~76 degrees F.
4. We have had a 2400 kWh/year Wind Source contract for many years, which almost covers the electricity not produced by the solar-electric system.
5. Indirect/Direct (Master Cool) evaporative cooling, which is manually staged starting with airside-economizer cooling, and then either or both of the evap-cooling modes, depending on forecasted outdoor night-time temperatures. The house is so well insulated and has enough thermal mass that it can be sub-cooled at night (off-peak hours) down to ~65 degrees F and not require daytime cooling. Cooling is typically started between 8 and 10 PM in the middle of the summer, and it turns off automatically with a thermostat. Windows are closed during the day, and certain windows are opened at night for whole-house cooling.
6. The roof joists have a vertical 14-inch leg along the perimeter to allow full-depth attic insulation, substantially reducing heat loss and eliminating the possibility of ice damming.
7. Roof overhangs were designed to allow maximum solar gain in the winter and minimal gain in the summer in the upper level. The lower level is partly underground and maintains temperatures ranging from 65 to 75 degrees through-out the year.
8. Airtight drywall approach was used to practically eliminate infiltration and for the vapor barrier, eliminating the need for polyethylene “vapor barriers” that break down over time. All perimeter electrical outlet and switch boxes were foam-sealed or caulked to eliminate infiltration.
9. Air-to-air energy-recovery ventilator that has operated 24/7 since the house was built.
10. Cellulose insulation (recycle newsprint paper) for all interior and attic insulation. This was one of the few available recycled materials at that time.
11. Low-flow plumbing fixtures since the house was built.
12. Minimal tall-fescue lawn to meet home-owners association requirements with large-droplet sprinkler system on a timer that is adjusted to minimize water consumption. Only one application of fertilizer in the fall.
13. Drip irrigation is used extensively for flower beds and vegetable garden.
14. No dirt was hauled off the site, since the dirt that was dug out was used for a berm on the back side of the property. All the wood scraps could fit under a folding card table and were recycled. Drywall and other scrap that filled one pick-up truck bed was taking to the local land-fill.
15. An interior environmental feature is the low noise on windy days because of the airtight construction, super-insulated walls and well-insulate attic, and Heat Mirror glazing in casement, awning and picture windows.

3. Energy Conservation Features:

1. Nominal R-30 above-grade walls: two-coat stucco exterior, 1.5-inch polyurethane insulation, ½-inch plywood sheathing, 2x6 studs on 24-inch centers (sprayed-on cellulose insulation), and ½-inch interior drywall. Below-grade insulation: exterior R-10 closed-cell polystyrene, 8-inch concrete foundation, 2x4 interior furring on 24-inch centers with sprayed-on cellulose insulation. Under-floor insulation four-feet in from perimeter: 2-inch closed-cell polystyrene.
2. R-45 cellulose attic insulation extending full-depth to the perimeter.
3. Insulated metal doors with magnetic weather-stripping.
4. Wood-frame windows with extruded-aluminum exterior and ”tuned” Heat Mirror glazing (HM88 on south and north and HM66 on east and west, and either argon or xenon fill in the replaced glazing – almost all of it). Most of the replaced south glazing has a center-of-glass R-value of 9 due to the Xenon fill.
5. Air-to-air heat-recovery ventilator (ERV) which is the only exhaust for the bathrooms, laundry room and vicinity of the kitchen, with over-ride switches for timed operation of high-speed exhaust.
6. Airtight construction, which was proven to be so because the kitchen hood exhaust would not work unless the kitchen window was opened.
7. Kitchen hood exhaust has a motorized damper interlocked with the fan motor that also opens a bypass on the ERV to provide make-up air.
8. Sealed-combustion back-up domestic-water heater and sealed-combustion condensing furnace.
9. Low-wattage lighting with 3-way and 4-way switching to facilitate turning lights on and off. Occupancy switch in a walk-in closet.
10. All the energy-conservation features, except for the active solar systems, had a simple payback of 2 to 3 years!
11. Trees were planted in 1986 on the east and west side to provide shading from late Spring through early Fall.
12. Windows were placed to provide uniform solar gain and distinct views of the outdoor landscaping, and good daylighting.

4. Outreach:

1. We have given presentations and given tours over the years to prospective owner-builders and university students. We have a PowerPoint presentation showing the construction process and energy-efficiency details.
2. The house is in a publicly viewable location in North Boulder.

Residential, Renovation:
Golden Oldy Cyclery & Sustainability/ Stevens Residence

Steve Stevens & Paul Kvasnovsky

Summary Description:
This passive solar conversion of a 1979 home features many solar and energy efficiency gadgets including envelope south walls, airlocks, super insulation (R-100 roof, R-68 walls), sealing, thermal mass, and daylighting floors. The foot wide envelope feeds the attic to heat the home. This attic area serves not just as collector but as an accessible solar food dryer for greenhouse and garden produce. The lowest level of the passive addition is the greenhouse incorporating a climate battery as well as water based thermal storage. The home overproduces over 9,000 KWH per year which has been fed to the grid.

Grossly Energy Positive.

• Net Zero Electricity Since 2006.

• Net Zero total Energy since 2008

• Carbon Negative SINCE 2008

• Producing Fruit (Tropical and Temperate)
  and Vegetables from the former landscaped
  0.19 Acre lot.

• Powering 2 Plug In Cars… While Selling ~ 8500 KWH surplus power back … to the grid annually from the Rooftop.

More Information

“Home & Museum Powered By the SUN & FOOD POWERED BY the SUN, BIOCHAR and ALPACA POO… and delivered FARM to TABLE by FOOT”
http://youtube/t3jvittg60I

The goal is to disconnect from the natural gas line.

Gas Therms

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	TOTAL
2002	195	173	158	81	61	22	12	15	13	46	126	193	1095
2012	30	20	3	0	0	0	0	0	0	0	0	0	53

Air Transfer Box

The Air Transfer box - in the attic - in preparation for applying wiring and ducts.

It has 2 chambers:

The left is the output chamber feeding the powered and heated air to the
Living room through two 12-inch ducts... and to the master bath (and hall) through one 10-inch duct.... and down through the old chimney chase to the Utility room (with the heat pump water heater) through one 6-inch duct which is slipped down the old furnace flue.

The Furnace blower motor is in the right chamber (the input chamber) ... and the inputs from the sunroom (two 10-inch insulated Ducts at right and one one 10-inch on opposite side) Will supply the sun warmed air.

The whole box is lined with aluminum coated fiberglass matting... on top of a Poly-Iso R-10 box. Everything is caulked and taped with Aluminum Tape for total seal.

The 4 speed blower motor will be only wired for 2 of the settings: 1/5th HP and 1 /3. If I want to change that later I can have it be up to 3/4 HP. There will be a user select on the 2 available speeds adjacent to the hall thermostat.

Thermostats

Two Thermostats will also control operation:

• One in the hall to specify demand (standard line switching heating thermostat) and

• One in the upper sunroom to specify if the sunroom has the adequate heat to send ( a standard line power Evaporative Cooling thermostat)