Tuesday, August 12, 2008

Low impact sunroom in Rhode Island



Great details make this addition better for the pocketbook and the environment

The owners of this traditional RI home wanted to replace a cramped enclosed porch with a comfortable multipurpose addition, better views of a nearby river and a better expression of their eclectic taste. Although the clients’ initial plans didn’t specifically focus on green building, Joseph Cracco, of Modern Yankee Builders, challenged himself to raise the project’s level of sustainability without raising the cost. The result is a bright and airy family room, an expanded second floor office and a new basement that perform better than the family had imagined possible.

You could say that the motto of Joe’s team was “tread lightly”. Almost 19 tons of concrete were reclaimed by grinding the old foundation into gravel for road beds. The rest of the construction debris was hauled to New England Recycling, in Taunton, MA, where about 84% of it was separated for reuse. After the original porch was carefully deconstructed, the new work shared as much of the original footprint as possible. Site disturbance was kept to a minimum - existing bushes were temporarily moved then replanted; turf was quickly re-established in some areas and replaced with planting beds in others; the new gas line was even tunneled to avoid digging a trench in the front yard.

Modern Yankee Builders did all this - on top of the steps they took to make the addition durable and energy efficient. The structure is built with advanced framing on top of a thoroughly waterproofed ICF basement. To allow for the decorative rafters and sheathing inside the new space, and to create a good thermal break, XPS insulation was installed outside of the roof deck. The whole exterior got a well sealed drainage plane and air barrier. After that, Sleepers, CDX, a self adhesive water shield and 30 year asphalt shingles created a fully vented roof surface and hard-wearing FSC certified cedar shingles wrapped the walls. Joe’s dedication and attention to detail paid off. The homeowners got a place they can be proud of for years to come, with little added burden on the budget or the environment.

Team:
Builder: Joseph C. Cracco, Modern Yankee Builders
Architect/Designer: Katrin Boening and Sean Solley, Solleydesign

Specs:
Location: Barrington, RI
Completed:2007
Cost: $180,000 including site work and landscaping
Size: 635sq.ft.(275 sq.ft. room added to basement, 275sq.ft. 1st floor family room/mudroom, 85sq.ft. additional space added to existing 2nd floor office)

Construction:
Foundation type and R-value: ICF basement (R-22)
Wall construction and R-value: 2x6,24” o.c., XPS sandwiched within headers (R-10), fiberglass batts (R-19)
Windows: double glazed, low-E (R-2.9, SHGC - .29)
Roof construction and R-value : 2x6 T&G roof decking over exposed rafters, 4” XPS foam board with taped seams(R-24), 5/8” OSB sheathing and 2x sleepers over rigid foam

Energy specs:
Heating equipment: new hydronic baseboard tied into existing loops on each floor of house
Air conditioning: (only in existing top floor) variable speed air handler, condenser (13 SEER)

Water efficiency measures used in this project
- Reduced lawn area (less irrigation demand)

Energy efficiency measures used in this project
- Bank of windows providing ample daylighting and natural cooling
- ICF foundation
- Continuous XPS installed above roof decking (virtually no thermal bridging)
- Rigid foam insulation built into window and door headers
- Extremely thorough air sealing
- Electronic programmable thermostat
- Variable speed air handler with 13 SEER condenser

Green materials and/or resource efficiency used in this project
- Ensured durability through meticulous detailing of drainage and ventilation
- Sided with FSC certified cedar shingles
- Demolished foundation was ground into gravel for reuse
- Other construction debris was hauled to a regional recycling center with an 84% recovery rate

Indoor air quality measures used in this project
- Temporary filters covered HVAC returns during construction
- MERV 11 filters fitted to AC returns after construction was complete
- All materials kept dry during construction (just-in-time delivery, tarps above and below any stored lumber)
- Formaldehyde-free Advantech OSB subfloor

Lessons Learned:
Modern Yankee’s trek to the 2007 International Builders’ Show left them pleasantly surprised at how sustainable their standard practices already were. They still logged plenty of hours of research for this addition. This not only made the results better than the clients had asked for, but further integrated green concepts into Modern Yankee’s “business as usual”, proving that quality, affordability and sustainability can all go hand in hand.

Monday, August 11, 2008

1970s Home Goes Net Zero



A deep energy retrofit that outperforms most new homes

Intensive renovation has made this modest ranch house in the suburbs of Boulder, Colorado an example of what any green builder strives for - a net zero energy home. With an extreme insulation retrofit, a 6 kW photovoltaic array, and an evacuated tube solar hot water system, the build team expects this house to produce 130% of its own energy needs. A grid tied system allows the excess electricity to be “stored” until occasional winter cold snaps demand that the 9-kW modulating electric boiler fills in.
Motivated owners, a dedicated group of designers, consultants and builders and state renewable energy incentives, allowed the project to shoot for lofty goals. Carefully balancing the value of individual improvements by looking at them as parts of a bigger system was crucial. Energy use monitoring and computer modeling helped maximize overall efficiency of the home. A Web Energy Logger (WEL) was permanently installed to monitor performance and plan for future energy upgrades.
Starting from the ground up makes it relatively easy to insulate structures like the 700ft addition included in this project. Retrofitting existing buildings is not always as straightforward. Together, Eric Doub of Ecofutures Building, and owners John and Vicky Graham decided that wrapping the home with additional 2x4 framing and sprayed polyurethane foam would be the least intrusive method. Although some of the work replaced upgrades that were only 5 years old, and the cost was on par with a typical high end renovation, continually rising energy costs made John and Vicky’s choice to create their energy efficient dream home, a great long term investment.

Team:
Builder: Eric Doub, Ecofutures Building, Inc.
Architect/Designer: Andy Johnson, DAJ Design

Specs:
Location: Boulder, Colorado
Completed: 2006 - 2007
Bedrooms: 3
Bathrooms: 3
Cost ($/sf): $81/sq.ft.basement remodel, $250/sq.ft. main floor and addition (including renewable energy systems)
Size: 1000 sq.ft. basement, 1000 sq.ft. existing main floor, 700 sq.ft. addition

Existing:
Foundation type and R-value : concrete walls covered with 1” XPS on interior (R-5)
Wall construction and R-value: existing 2x4 framing filled with blown cellulose, 2x4 framing added to exterior and filled with Icynene spray foam (R-28 total)
Windows: Duxton foam-filled fiberglass window frames with 2 layers Heat Mirror, Krypton/Argon filled (R-7.1)
Roof construction and R-value: 8” open cell foam -(SPF) and 12” blown cellulose (r-70)
Garage: attached; thermal and air separation

Addition:
Foundation type and R-value: 6” ICF crawlspace (R-30)
Wall construction and R-value: 2'x6' frame, faced with 1 ½" resilient channel on interior creating a 7" wall cavity filled with Icynene spray-foam (R-27)
Windows: Duxton foam-filled fiberglass window frames with 2 layers Heat Mirror, Krypton/Argon filled (R-7.1)
Roof construction and R-value: SIP roof (R-42) with 3.5" SPF in dropped ceiling (R-50 total)

Energy specs:
Conditioning equipment:
- Operable windows and motorized skylight for ventilation and cooling
- Solar hot water - 180 evacuated tubes, 2 - 168 gallon, insulated storage tanks (R-80)
- Backup from on-demand 9-kW modulating electric boiler
- EPA-approved wood-burning fireplace
Water heating equipment: Same as space heating
Projected total electricity consumption: 6,300 kWh/yr
Projected total electricity production: 9,600 kWh/yr
Actual : June 2008 ~300kW surplus (sold back to utility company)

Water efficiency measures used in this project
- Dual flush toilet
- Xeriscaping
- Drip irrigation

Energy efficiency measures used in this project
- Natural daylighting
- CFLs throughout home
- Direct-from-solar-tank hot water dispenser to reduce energy demand in cooking
- Insulation far above recommended standards
- EnergyStar rated ceiling fan
- Existing Energy Star washer and dryer, plus clothesline
- Separate switch to eliminate phantom loads from electronics

Green materials and/or resource efficiency
- 90% (by weight) of construction waste either recycled or repurposed
- FSC-certified lumber for framing
- Recycled plastic decking
- Water-based floor finish
- Clay plaster
- Concrete and sorghum-based countertops
- Oriented-strand board subfloor

Indoor air quality measures
- Energy Recovery Ventilator (ERV)
- Linoleum tile with low-VOC adhesives
- Formaldehyde-free cabinets
- Low-and zero VOC paints and stains
- Natural wool carpet
- Natural clay plaster walls absorb odors, sounds, & indoor air pollutants

Alternate Energy Utilization
Photovoltaic power: Grid connected solar PV (6 kW)
Cost: $25,000
Solar water heating: Evacuated tube solar hot water system provides 90%–100% of domestic hot water as well as space heating using in-slab radiant tubes
Cost: $34,000

Green Building Product Sources:
OptiMiser, Web Energy Logger
American Clay Plaster

Lessons Learned:
Aside from the obvious utility cost savings, this remodel aims for the goal of passive survivability - the ability of a building to remain habitable when utility disruption occurs during extreme outside temperatures. The actual performance of the home falls slightly short of projections - something that builder Eric Doub believes could be tempered by the use of movable window insulation. “My recommendation is to have at least some cellular shades, if just to reduce convective heat transfer.” That’s getting pretty deep into the details of energy efficiency. Good Job Eric!

Thursday, June 12, 2008

Energy Value Housing Award -- Chino Valley, Arizona


An academic pursuit providing real world results

This luxury home is representative of a growing number of programs that provide both training in environmentally responsible building practices as well as real sustainable housing. It is the product of the Residential Building Technology (RBT) Program at Yavapai College, in Prescott, Arizona. In 2007, this project was given an NAHB Energy Value Housing Gold Award while also complying with several other sets of standards including LEED, EEBA and ALA HealthHouse.

The Longview House was designed to conform to the RBT program's mission, which strives to produce healthy, durable, affordable and efficient housing. Nearly every process was addressed in making the home efficient to build as well as live in. The use of pre-manufactured roof trusses and foundation walls expedited construction, while carefully installed insulation, an extremely tight building envelope and a rainwater collection system will limit future energy and resource needs.

The RBT program is equally concerned with the environmental impact of their work. Careful planning helped minimize disturbance of the site and its existing vegetation. The addition of drought tolerant landscaping further inhibits storm-water runoff - an important concern in this arid and hilly location.
Although it may be atypical with its use of university student labor, this project is a great example of how smart design can facilitate increased sustainability within a typical budget. An NAHB Energy Value House judge’s comment - “if only every house built in the U.S. could have the oversight of this project - our houses would be energy efficient and durable”, is a testament to the commitment of the RBT faculty and students.

Team:
Builder: Yavapai College Residential Building Technology Program, Tony Grahhame Director
Architect/Designer: Yapavi College Architectural Design Students and Staff

Specs:
Location: Chino Valley, Arizona
Completed: 2005
Cost ($/sf): $90/sq.ft (not including cost of student labor)
Size: 3202 sq.ft.

Construction:
Foundation type and R-value: Combination - slab on grade xps foam at edge (R-5), crawlspace ICF (R-16), basement integral XPS and blown in cellulose ((R-26.5)
Wall construction and R-value: 2x6 @ 24” o.c., 2” XPS and 5 1/2” unfaced fiberglass batt (R-29)
Windows: Double pane, low-e, argon filled. SHGC = .30 - .59; U- factor = 0.30 -0.35
Roof construction and R-value: Engineered trusses, blown-in cellulose (R-38)
Garage: Thermally and pressure isolated from living space

Energy specs:
Conditioning equipment : 14 SEER AC system, 56,672/80,960 BTU dual stage direct venting gas furnace
Water heating equipment: Solar domestic hot water, 40.9sq.ft. flat plate collector, 80 gal. storage tank w/ electric backup
HERS Rating: 90.5 (5 star +)

Water efficiency measures used in this project
· Low flow toilets, faucets and shower heads
· Water conserving dishwasher
· 1250 gallon rainwater collection system
· Gray water distribution system
· All hot water taps within 30ft. of hot water storage tank

Energy efficiency measures used in this project
· Whole-house Energy Star interior and exterior lighting package with CFL bulbs.
· Extremely tight building envelope (blower door test 0.96 @50 Pascals)
· Roof overhangs optimized for summer window shading and winter solar gain.
· Energy Star appliances including dishwasher, ceiling fans and ventilation fans
· Sealed ductwork, leakage measured at 0cfm @ 25 Pascals
· All ductwork is located within the conditioned space

Green materials and/or resource efficiency used in this project
· Decking, ICFs, wall and ceiling insulation all include recycled content
· Recycled cardboard and metal construction materials

Indoor air quality measures used in this project
· Balanced whole house air exchange system with MERV-10 and HEPA filtration
· All construction materials contain low or no VOC
· Low formaldehyde content in particleboard cabinets

Alternate Energy Utilization
Photovoltaic power: 2 KW (12 Shell 165w Powermax Ultra panels)
Solar water heating: 40.9sq.ft. SunEarth flat plate collector, Solaraide 80 gallon hot water storage tank/electric backup heater; cost $_________

Lessons Learned
In much of the country we pretty much take our abundant supply of clean water for granted, but a growing number of homeowners have to think twice before they wash their car or water their lawn. Builders in the Southwest have been dealing with this for ever, but pollution, climate changes and development pressure could make this a big concern just about anywhere. “Water could be the next expensive commodity for homeowners”, says Tony Grahame. He believes a whole system approach is necessary to make a real difference. Large rainwater catchment systems and separate grey water plumbing can eliminate the burden that landscape irrigation puts on municipal water supplies in this region, but efficient plumbing layout and low flow fixtures are just as important. This is one place where a little planning can reap big rewards without much expense.

Thursday, May 1, 2008

Energy Value House, Prescott, AZ


This house proves that green doesn't mean expensive.

This rather typical single story ranch house is very uncommon in a lot of ways. It's super energy efficient, it has superior indoor air quality compared to most new houses, and it cost $55/square foot to build. That it was so cheap to build flies inn the face of green building conventional wisdom. How did they do it? Tradeoffs. Fewer studs means more room for insulation. Roof overhangs and quality windows means a smaller AC system. Unvented roof means the AC and ducts can go in the attic.

The cost savings began with the site: a substandard lot (flood plain issues) was engineered to bring it up to code standards. While there was a high level of engineering, it was kept localized as much as possible -- many existing trees and shrubs were spared. No toxic pesticiedes were sprayed before construction, the house is oriented along an east/west axis to maximize southern exposure for day lighting , passive warming in winter, and solar collectors on the roof which heat the water for free.

Advanced framing, exterior foam insulation, and an unvented roof yielded an extremely tight envelope -- .63 ACH, at no "extra" cost. Smart plumbinf layout cuts the amount of time waiting fore hot water to reach a tap, which saves water. Much of the techniques used in this house are old news: insulating a slab keeps it warm and dry, foam sheathing on the outside keeps the framing warm and dry, so mold isn't likely to gain a foothold, Better windows are worth it.

Team:
Builder: Yavapai College Residential Building Technology Program, Tony Grahame Director.
Architect/Designer: Prescott area Habitat for Humanity

Specs:
Location: Prescott, Arizona
Completed: 2006
Bedrooms: 3
Bathrooms: 2
Cost: $55/square foot
Size: 1,189 sq.ft.

Construction:
Foundation type: Slab on grade with XPS foam at edge (R-5)
Wall construction: 2x4 @ 24 in. o.c., 1 in. XPS foam and dense pack cellulose (R-19 total)
Roof: Raised heal trusses, 8 in. foam sprayed to underside of roof deck (R-32, unvented).
Windows: Double pane, low e, argon filled. SHGC = .33 to .35; U factor = 0.32 to 0.35 (R-3)
Garage: Attached, insulated and sealed from living space

Energy specs:
Conditioning equipment: 14 SEER Energy Star AC system; 40,000 BTU direct vent gas furnace (92.0 AFUE)
Water heating equipment: Solar domestic hot water system, 40.9 sq.ft. flat plate collector, 80 gal. storage tank with electric back up
HERS Rating: 57 (5 stars)

Yearly Energy Use (electric, gas, heating oil combined)
Modeled or predicted: (kBTU/sf):
Actual : (kBTU/sf):

Water efficiency measures used in this project

  • Low flow toilets, faucets, and shower heads
  • Water conserving Energy Star dishwasher
  • All hot water taps within 30 ft. of hot water storage tank

Energy efficiency measures used in this project

  • Roof overhangs optimally sized for window heights to allow summer window shading and winter sun entry for passive solar heating.
  • Energy Star interior and exterior lighting package with CFL bulbs.
  • Extremely tight building envelope (103 cfm @ 50 pascals equivalent to 0.63 ACH)
  • Energy Star appliances including dishwasher and refrigerator
  • HVAC requirements calculated and sized appropriately
  • Programmable thermostats
  • Sealed ductwork, Duct Blaster leakage measured 14 cfm @ 25 Pascals

Green materials and/or resource efficiency used in this project

  • Advanced framing
  • house designed in 2ft. increments to conserve materials
  • Cellulose insulation made with recycled paper
  • Composite decking contains recycled plastic
  • cardboard and metal construction waste was recycled


Indoor air quality measures used in this project

  • Balanced whole-house ventilation with MERV-10 and HEPA filtration.
  • Moisture mitigation techniques including damp-proof subslab, soil surface gaded away from house, foundation drains around perimeter, plastic sheet under slab, wall system design allows drying to inside and outside, right sized HVAC controls humidity
  • Garage is pressure isolated from living space
  • Radon venting
  • Only hard surfaced flooring, no carpet
  • Multiple return grills provide pressure balancing between rooms
  • All ductwork is within conditioned space
  • Spot ventilation in bathrooms


Certification:
EnergyStar: qualified based on HERS score (57)
NAHB green score with breakdown of points earned/available:
Other certification with breakdown of points earned/available:

Alternate Energy Utilization
Solar water heating (type and size of system): 40.9sq.ft. SunEarth flat plate collector, Solaraide 80 gallon hot water storage tank/electric backup heater; cost $_________


Green Building Product Sources:

Eljen In-Drain Geotextile Sand Filter System

Lessons Learned:

Because of the small lot size, a standard septic leach field was not feasible for this project. Tony Grahame, director of Yavapai College's Residential Building Technology program, solved this problem with the Geotextile Sand Filter system made by Eljen. A plastic grid covered in a special drainage fabric allows for more surface area, more volume and more air infiltration than the typical bed of gravel. The result is that you get a leach field that will likely perform better while taking up 50% less space. Using this system was the only way to build a home on this particular site, but it would be valuable to anyone trying to keep site disturbances to a minimum.

LEED Platinum in Freeport, ME



From top to bottom, the platinum-rated house embodies a best-practices approach to the building envelope. The framing makes extra room for insulation with 24-in. on-center spacing, two-stud corners, and offset rim joists. Damp-spray and dense-pack cellulose insulation does an excellent job of filling wall cavities. To make sure they didn’t miss anything, the project team did a blowerdoor test before the drywall went up so that any leaks could be filled.

The 2.6-acre rural maine lot wasn’t eligible for many of the 'lot location' credits, but the team did pick up a few points for not disturbing wetlands, building in a floodplain, or on agricultural land.


To mitigate the effects of development, the property has a permeable gravel driveway that absorbs water runoff. even with a septic system installed, more than 40% of the site was left undisturbed. excavated and trafficked portions were replanted with a mixture of native wildflowers and drought-resistant fescue grass.


Team:
Builder: Wright-Ryan Construction
Architect/Designer: Richard Renner

Specs:
Location: Freeport, Maine
Completed: 2006
Bedrooms: 4 plus office
Bathrooms: 2 1/2
Cost: $230/ square foot
Living space: 3200 square feet

Construction:
Foundation type: ICF Basement, R-23
Wall construction: 2x6, 24 in. o.c. with dense pack cellulose, R-R-21
Windows: Thermotech triple glazed, U-.15 (R-6.7)
Attic: R-49 loose fill cellulose in ceiling
Garage: Attached.


Energy specs:
Conditioning equipment (explain): Radiant floor and wood stove. No cooling system
Water heating equipment: Solar water heater
HERS Index: 42

Water efficiency measures used in this project
Lavatory faucets: max 1.5 GPM
Shower heads: max 1.5 GPM
Toilets: max 1.1 GPM, dual flush (Mansfield EcoQuantum)


Energy efficiency measures used in this project
Fluorescent fixtures represent more than half of the installed lighting, solar hot water system is plumbed so that excess capacity assists the radiant heating system, siting of building and layout of windows facilitate passive solar heating, effective daylighting and natural ventilation

Green materials and/or resource efficiency used in this project
FSC certified lumber and advanced framing techniques. Wheatcore doors, Dakota Burl cabinet panels, recycled content floor tile, fly ash in concrete, recycled content metal roofing, no carpet, low-VOC paints, and cellulose insulation. Locally sourced materials include birch flooring, stair parts, framing lumber, cedar siding, and granite countertops.

Indoor air quality measures used in this project
Heat recovery ventilator with air distributed through ducts. Low VOC paint was used throughout. The garage has a ventilation fan actuated by the garage door openers. There is no air conditioning.

Certification:
LEED-H Platinum, overall score: 95/130
Innovation and design 9/9
Energy and atmosphere 27/38
Location and linkages 3/10
Materials and resources 14/14
Sustainable sites 15/21
Indoor environmental quality 15/20
Water efficiency 10/15
Awareness and education 2/3

Alternate Energy Utilization
Photovoltaic power (:2 KW
Solar water heating :3 collectors

Green Building Product Sources:

Lessons Learned:
The house has performed very well. The build team intially intended the house to be smaller, but a real estate consultant recommended building a master bedroom suite over the garage. Also, the house is in the suburbs, which does not help the problem of sprawl.

Wednesday, April 30, 2008

Approaching Zero Energy in Concord, MA


An American classic found in almost every town in the country. The plaster was in great shape and the layout was excellent, so other than adding a few windows and updating the kitchen, we didn’t want to disrupt the interior too much. We almost doubled the living space of this house without adding an inch to the footprint. And the utility bills were cut by 60%.

SPECS:

Conditioned space: 2,000 before, 3,600 after
Bedrooms: 4 before, 4 after
Bathrooms 1 1/2 before, 3 1/2 after
Cost of renovation: $100 per sq. ft.
Annual utility cost:

  • Gas $2,400 before, $858
  • Electric $960 before, $471





STEPS TOWARDS ZERO ENERGY:

1. Upgrade the mechanicals:

  • Furnace: sealed combustion 92% AFUE gas boiler (Munchkin boiler, www.htproducts.com)
  • AC: 13 SEER split system in conditioned space
  • Hot water: 85% efficient SuperStor tank attached to boiler.
  • Outside air is supplied to the return plenum of the efficient air handler; 5 in. pleated media filter in the return path on each air handler.
  • Energy efficient low sone exhaust fans in all bathrooms, fully ducted exhaust fan over kitchen stove

2. Bring the basement and crawlspace inside the house -- New 3 in. slab over 2 in. XPS over 1/2 in. drainage mat over old slab; 3 in. closed cell foam sprayed on perimeter walls (R-21), steel studs and drywall over foam insulation as per code.

3. Super insulate and air-seal the roof (R-60) -- R-39 (6 in.) High Density Spray Foam on underside of roof sheathing, R-20 two layers (staggered seams) of foil faced Polyisocyanurate roof deck insulation (3 1/2 in. total thickness).

4. Replace the windows with double glazed low-E replacement windows.

5. Insulate the walls (R-40) -- Cellulose blown into existing 2x4 walls (R-13), two layers with staggered seams of foil faced polyisocyanurate sheathing (R-26).

6. Buy Energy Star (or better) fixtures and appliances --refrigerator,dishwasher, stacked washer/dryer.


MATERIAL NOTES:

  • We used closed cell foam in the roof because the rafters were only 7 in deep. Closed cell foam has higher R-value per inch. This allowed us to have the highest possible R-value on the roof without rebuilding the rafters.
  • Foil faced Polyisocyanurate to the exterior of the walls gave us the highest R value per inch for the exterior walls. We didn’t want to disrupt the interior plaster to spray foam into the wall cavities.
  • Windows - The tilt-in replacement windows were installed from the exterior rather than from the inside so that we could build out the jamb thickness to accommodate the deeper walls. New windows (Andersen, to match the replacaments) were added to the back yard to provide better views to the pond.

LESSONS LEARNED/WHAT WOULD WE DO DIFFERENTLY?
Better windows would be the next place to reduce energy loads in this house. A triple glazed unit, with heat mirror technology might further reduce the heating load allowing us to get closer to zero.

Saturday, April 26, 2008

Energy Upgrade in Sommerville, Massachusetts

This is a energy retrofit of a two family Victorian located in a historic district. While historic districts can be quaint, they can also be difficult places for energy retrofits. The enclosure was difficult to upgrade because we weren’t allowed to remove siding or replace windows. We converted the over/under configuration to side by side units and brought the attic into the conditioned space to boost living space. One side is the current home of Building Science Corporation; the other is a rental unit. The basement was made into a warm dry storage area for our massive book inventory. Energy consumption was cut by 50%.

STEPS TOWARDS ZERO ENERGY:
1. Upgrade the mechanicals:

  • Furnace: Replace 60% efficient boiler (200,000 Btu) with a two smaller Hydro-air systems. A sealed combustion condensing gas boiler (80,000 Btu, 90% efficient) with water tank (SuperStor Ultra) and a condensing hot water heater (90,000 Btu, 85% efficient) make domestic hot water and provide space heating.
  • AC: Window units replaced with direct expansion units (14 SEER) placed on pads in the yard. Energy efficient low sone exhaust fans in all bathrooms, fully ducted exhaust fan over kitchen stove

2. Bring the basement inside the house.

  • Drainage mat over existing concrete floor, 2 in. extruded polystyrene (XPS) insulation, topped with a 3 in. concrete slab.
  • Sill timbers were lifted off of the brick walls and separated with a capillary break (roofing membrane). 2 in. closed cell foam sprayed to the inside of the foundation and then separated from the interior space with a thermal barrier as required by the building code. In this case, a 1 5/8 in. metal stud wall provides support for paperless drywall (DensGlass gold, www.gp.com).

3. Super insulate and air-seal the roof (R-50)
  • Insulation removed between second floor and attic.
  • Top plate connected to attic rafters and closed with building paper.
  • To adequately support the load of the slate roof, we had to increase the rafters from 2x8 to 2x12. We filled these deep cavities with less expensive open cell foam (www.Icynene.com) (R-40).
  • 2 in. XPS below rafters (R-10) provided extra insulation as well as vapor diffusion resistance.

4. Upgrade Windows. We replaced 1/3 of the windows with tilt-in replacement windows. The balance was done with replacement sashes into the existing frames (see materials notes below).

5. Insulated walls. We were able to remove siding to spray in low density open cell foam in 1/3 of the wall area, the remainder of the walls are still uninsulated (see materials notes below).

6. Energy Star (or better) fixtures and appliances
  • Energy Star refrigerators (GE and KitchenAide), dish washers (Bosch), and stacking washer/dryers (GE).
  • 60% of the light fixtures used were pin based Compact Fluorescent fixtures. The others were period fixtures and were fitted with screw in CFL bulbs.

SPECS:
Completed:
2003
Bedrooms: 4 before, 4 after
Bathrooms: 2 before, 4-1/2 after
Cost of renovation: $125 per sq. ft.
Conditioned space: 2,150 before, 2750 after plus 1,000 sq. ft. of dry warm basement storage.
Annual utility cost: Gas $3,600 before; $1,474 after;Electric $1,200 before; $830 after

MATERIAL NOTES:
Because the roof was covered in slate and the historic commission wanted it to stay in place, all insulation had to be from the roof deck towards the inside. We used open cell foam because the rafters were 12 in. deep; this coupled with 2 in. of XPS on the underside gave us sufficient overall R-value (R-50).

Because the house is in a historic district, we were severely limited in our insulation strategies. On one side we were allowed to remove siding, install house wrap, blow in open cell foam insulation, and replace the siding. On all other sides, we were not allowed to remove the siding in order to tighten up the wall sheathing. For this reason, we were unable to blow in any type of insulation.

The Historic commission allowed us to replace the window frames in the locations where the siding needed to be replaced. All other windows were fitted with new double glazed low e sash. This didn’t improve performance much because the openings were not perfectly square. New windows are double glazed, low-e (www.marvin.com).

Old solid wood doors were salvaged and weather-stripped; some were replaced with energy efficient doors featuring double glazed, low-e lights (www.thermatrue.com).
WHAT WOULD WE DO DIFFERENTLY?
Historic commisions and committees all over the country have interest in windows, chimneys, roof finishes and siding that often conflict with best practice where long term durability of the structure and its energy efficiency are concerned. We compromised and used all wood simulated divided light replacement sashes from Marvin for 2/3 of the window units. Because the openings were so far out of square, the sashes never fit right, and had to be fussed with more than we had expected. We were also not prepared for the battle regarding the siding replacement, and left it until a future phase. It is our intention to go back and replace the balance of the siding, and when we do that, we will blow cellulose into the remaining 2/3 of the wall cavities, and will add insulation sheathing at that time as well. We will brace ourselves for the dialog with the historic committee.