The Greening of an Architect

by Pamela O'Malley Chang

Despite our best efforts to recycle the construction debris, we made several trips to local landfill sites to unload waste.

The concrete contractor installs the subfloor in the lightwell section of the addition. It increases the thermal mass here, improving wintertime heat gain.

Looking up into the two-story light well, you can see the ample south-facing sun exposure that the renovation allows.

After almost 61 years, the walls of the 1936 addition finally got a blanket of fiberglass insulation.

My natural linoleum flooring has many benefits, including the fact that it is biodegradable and thus can be shredded and composted after it has lived out its useful life.

Here I am applying low-VOC paints to the walls of the new study.

The PV system on my roof is connected to the power grid so I can sell to my local utility any electricity I don't need.

In 1996, I received notice from my insurance company threatening loss of coverage on my Berkeley, California, home if I didn't install better foundations than the posts on concrete blocks that supported part of the house. Renovation was past due. The main house, built in 1913, was sound and needed only furnace and plumbing maintenance. It sits over a seismically sound basement. The 1936 addition, however--aside from its unstable foundation--had a leaky roof, no insulation, and an awkward floor plan and appearance. So, after 15 years of practicing architecture, design, and engineering, I became my own guinea pig--client, architect, engineer, and unskilled laborer--on a yearlong renovation project.

Eventually, the project came to include window replacement, foundation work, framing revisions, added insulation, new finishes, a new roof, and an electrical upgrade in the addition section of my home, as well as replacement of the heating system and corroded water pipes for the entire house. Just recently, I put a new roof and a photovoltaic (PV) electric system above part of the main house. Over the course of the project, I became a green architect and put into practice many of the environmental ideals I value. I also caught a glimpse of many building science issues that I have yet to learn more about.

Design

Previously, I had paid limited attention to environmental issues when designing buildings. During site planning, I typically assessed topography, local wind or weather patterns, views, and site features (such as roads, other buildings, or trees). These factors affected my choice of building placement, orientation, and, to a lesser extent, building layout and form. I used to feel that energy conservation was the responsibility of the heating-and-cooling-systems engineer or a building energy specialist. In treating my own home as a green renovation, however, I aimed to make environmental concerns a primary filter for all my design decisions. I kept in mind the mantra: "Reduce, reuse, recycle."

The plans I eventually produced incorporated several green ideas. Most of them are not obvious. Completing the seismic retrofit was arguably the best eco-friendly feature, considering that I live within a few miles of some major fault lines. This preventive measure will save my house from premature consignment to landfill burial. Equally important was my decision to invest in this house rather than add to suburban sprawl by building my once-dreamed-of country cottage getaway. Another basic choice was to keep the renovation within the old footprint of the home on the lot; I didn't need to take up more space, only to use space more efficiently.

As for the details of my renovation, I included the following passive solar features: increasing the total area of the home's south-facing windows, decreasing the total area of the north-facing windows, and adding larger window overhangs for shading summer sun. I put new insulation in the walls, roof, and crawlspace of the renovated addition (see Figure 1); these work together with the new windows to decrease temperature changes. On hot days, when cooling rather than heating is needed, I can open the windows at the top of the new light well to let the hottest air out and draw cooler air from the downstairs rooms.

My original design also included two active solar systems. One was a direct-flow solar water-heating system that supplements my gas-fired water heater. The hot water system pumps water between the water tank and a 2 ft x 5 ft solar-heating panel on the roof. A 5W photovoltaic (PV) panel powers the 3.82W solar water-heating system pump. Because of lousy freeze protection in the solar hot water system, I don't use it in the wintertime. The other active solar feature was a 105 CFM PV-powered fan to help circulate air in the light well and pump warm air through ductwork leading into the crawlspace for thermal storage (see below under "Building Envelope Materials").

I liked the idea of using solar to provide household electricity, but rather than install a PV power system immediately, when renovating the addition, I chose to just rebuild my flat, leaky roof with one pitched at the best angle for year-round direct sun--and to wait for PV costs to come down (California began to offer purchasing incentives for them in 1999).

Costs and Benefits

I finished construction on the renovation in April 1998, and in September 1999 I put up my PV electric system. My energy bills indicate that I initially reduced my electricity use by about 1 kWh per day (about 20%) by selecting more efficient fixtures (see Figure 2). With the added PV system, I expect to generate all my household electricity on an annual basis. Gas usage is variable but seems to average about 15% below previous years. Dollarwise, my gas and electric savings are probably less than $400 per year. The renovation, which was mainly done on just one-third of the home, clearly was not cost-effective on an energy basis alone.

The renovated portion of the house is, however, appreciably more comfortable. The second-floor bedroom no longer swelters, and the downstairs rooms are no longer drafty, with icy floors. The passive-solar concepts work--sunlight shines deep into the house through the light well windows all winter and is blocked by the roof eaves in the summer. Coming in late on a winter night, I feel the warmth retained inside the house even when the heat has been off all day. On hot summer days, opening the light well windows cools the whole house. The best pleasure, however, is the ample natural daylight throughout the house for most of the day. I like the renovation, and--now that the memory of dust and upheaval, major expense, and hard labor has faded--it seems worthwhile.

Choosing a Contractor

Sources should exist for locating green general contractors, but I didn't hunt for them because I wanted to learn how well ordinary people could do green construction. So, I collected names and references from colleagues, friends, and friends of friends, and relied upon my gut feeling. I did discuss my intention to become a green architect with the contractors during preselection interviews. All of the contractors whom I finally considered appeared competent, had good references, and expressed a willingness to try a proenvironmental approach.

Ultimately, I selected Randy Bundy, the contractor who was most excited by the possibility of our forging a design/build professional relationship for future green projects. Randy, however, did mostly small renovations. He introduced me to Joe Spitzley. Joe became my contractor for the foundation work, framing, siding, and window installation, while Randy took responsibility for the interior work, installing the solar equipment, waste management, and maintaining our ecological focus.

Minimizing Waste

Construction started in late April 1997. We began by designating areas for storage of new and waste materials. We stockpiled dirt, concrete rubble, clean wood scrap, mixed metal, cardboard, and assorted landfill trash. In theory, sorting should not require much extra effort; once accustomed to sorting, workers should have little more to do than pay attention to what they are hauling and which pile is which. Moreover, construction typically has distinct phases with different waste products generated at each step, so it should be easy to keep dirt, for example, separate from framing scraps. In practice, however, it did take more time: Joe estimated added disposal costs of 10%-15% to sort mixed wastes rather than allow them to accumulate until a hauling subcontractor could take a full load to landfill.

We did not do fine sorting, such as denailing lumber or separating embedded metal lath from stucco. Nevertheless, extra labor was needed for: additional footsteps to reach debris piles at varying locations, occasionally relocating waste piles, and taking things apart rather than doing smash-and-trash demolition. Sorting also required vigilance against garbage added to sorted waste piles by passersby and uninformed new workers, and carelessness. Eventually, it became a normal job task. Nevertheless, sorting always required every worker's help and someone with a strong environmental conscience to monitor and pick through the trash.

After sorting, we disposed of materials in various ways. Early in construction, dirt was our major waste product. I had planned to stockpile all topsoil for reuse, mixing it in with several years' accumulation of in-progress compost. After a week or two of hand excavation, however, we had a 16-ft-long x 4-ft-high pile filling a corner of my 35 ft x 100 ft lot--and we still had twice as much dirt left to dig. Joe hauled the remaining dirt to a local sanitary landfill where clean dirt was welcomed at no cost.

We disposed of small quantities of yard trimmings, cardboard, paper, and metals by adding them to my household curbside recycling; larger quantities had to go to a local solid-waste drop-off site. We also accumulated 2 or 3 cubic yards of concrete and plaster rubble. Eventually, I enlisted my brother's family and, bucket brigade style, we stowed the rubble in the crawlspace where, due to the fact that the floor is not insulated but the ground and stem walls are, it may have some value as thermal mass for storing heat.

We were also able to salvage a small fraction of other waste products. A local artisan cut down my dead toyon tree (a native species) for crafting into wood bowls. Other neighbors took pieces of the tree for firewood and plaster lath for kindling. We saved clean wood framing off-cuts for craft projects at a local playground. We sold the old aluminum sliding windows to an architectural salvage yard for $40--lunch for the work crew. We also gave the yard my old sinks, doors, and hardware. Finally, we salvaged for reuse a door, a wooden medicine cabinet, 1 x 4 redwood exterior trim corner boards, and 1 x roof sheathing that we turned into eave soffits.

We left the remaining materials, which we deemed unsalvageable, for unsorted landfill. Mostly, this category contained unclean wood; that is, painted, stained, and treated wood, and composite wood products (plywood, particle board, and so on). Other discards were plaster, mixed plaster and metal lath, tar-and-gravel roofing, asphalt shingles, plastic packaging, and bagged debris. We bagged sweepings, vinyl tiles that might have contained asbestos, and wood shingles with flaking lead-based paint. (I know of no special requirements for disposal of these types of waste materials for a small-scale renovation project.) Waste materials that our roofing and drywall subcontractors disposed of themselves probably also went into landfill. Although I have heard that both asphalt shingles and Sheetrock scraps can be reprocessed into recycled-content new products, I know of no local facilities that do so.

Finally, my contractor accumulated small quantities of hazardous materials, notably asbestos and lead paint chips. He packed the paint chips in an old paint can and wrapped the cement asbestos pipes in plastic. Wearing a respirator and Tyvek coveralls, he watered down, stripped, and bagged asbestos-containing duct wrapping and then put the bare metal ducts aside for recycling. He disposed of the paint chips, asbestos, and several cans of old paint at a local household hazardous waste collection facility.

Despite our efforts, this renovation still generated truckloads--tons--of landfill waste. I consider our waste management plans only half successful. The good news is that we diverted an estimated 12 to 15 pickup truckloads from landfill. We dumped perhaps another 30 to 40 loads. Unfortunately, under present conditions, this is the best-expected outcome.

Choosing Materials

Choosing materials is where homeowners can make the biggest contribution to changing the construction industry. My own experiences highlight the quirkiness of design decisions. My selections were often based on: standard engineering practice; what my contractors were used to; what was available at the time we were ready for installation; what cost significantly less in dollars, time, or research effort; or what just looked better.

Structural Materials

From a purely environmental perspective, probably the smallest foundation that is structurally adequate is best. Smaller foundations require less excavation, less concrete, and less steel. I would have kept my concrete blocks and posts if I could have. Instead, I sized my footings by ease of construction and engineering standards.

Originally, when I thought excavation could be done with a small bobcat backhoe from inside my garage/basement, I designed footings for a full-depth basement. Later, when we learned that there was insufficient headroom for the bobcat, I redesigned the footings to provide the crawlspace with minimum depth to obtain code-mandated clearance under the floor girders (allowing space for insulation and the rubble thermal mass). I designed extra-thick footings that protruded 6 inches beyond the exterior wall outline so that we could easily insert a concrete pump nozzle into the top of the formwork. In hindsight, I feel I should have designed thinner footings, and challenged my contractor to find a way to pour them, in order to use less concrete.

Using the least toxic materials has wide environmental benefits, and some choices might be particularly kind to construction workers. For example, we used alkaline/copper/quaternium (ACQ) preservative-treated lumber, a standard choice at my local lumber yard, for mudsills instead of the more common copper arsenate (ACA and CCA) preservative treatments. ACQ is chemically stable, and carpenters report that, unlike ACA and CCA, it does not cause skin or respiratory irritation. Perhaps ACQ-treated lumber is a better choice than redwood (whose sawdust is also a noted lung irritant).

For framing lumber, I had intended to use certified sustainably harvested lumber. Finding it, however, was not as easy as eco-advertisers suggested. If I had been ordering a boxcar of lumber, I could have placed a special order for whatever I wanted. If I had been inclined to drive 150 miles, I could have bought lumber from retailers who got it from a certified-sustainable producer. One local supplier expressed his intention to stock sustainable-harvested plywood but couldn't meet my time frame. In the end, I bought off-the-shelf lumber from a local lumberyard that assured my contractor that we were not buying wood from the controversial, threatened, old-growth Headwaters Forest. As it turned out, some of the Douglas fir that was delivered did bear the label of a certified-sustainable lumbermill; we did not specially order it, and it didn't cost more.

My contractor also found a lumber salvage yard that dismantled old warehouses and remilled their beams. He bought beautiful 10-ft lengths of clear, straight-grained, very dry and light redwood that we shaped into decorative brackets to match those under my original roof eaves. The cost for the remilled redwood was comparable to that for new wood, except for Joe's time in finding and fetching it.

Some alternatives to solid-wood framing are laminated wood, prefabricated wood trusses, steel, or resin-impregnated plastic-and-wood extrusions. Glued-laminated (glulam) beams, like many modern engineered-wood products, make efficient use of small pieces. They have now virtually replaced heavy-timber construction for framing. I used glulams as a ridge beam and as a floor girder spanning the width of my addition. I did not use steel framing, despite the advantage it offers in saving trees and being completely recyclable when a building is demolished, because it didn't make sense to introduce a new material that would require a whole different set of skills, tools, and fasteners. I did not use recycled-plastic-and-chipped-wood extruded "lumber" even for nonstructural uses. Yes, it is a recycled material, and yes, it is durable. I am prejudiced, however, against a composite product that is nonbiodegradable and cannot be recycled or reused.

Ultimately, I was not very creative about finding alternatives to conventional wood framing. 2 x 4s have a simplicity that permits easy cutting, shaping, drilling, and notching to fit around existing construction. I used plywood where I needed to replace floor or wall sheathing; paradoxically, exterior-grade plywood, which is bonded with phenol-formaldehyde, off-gasses less than interior-grade plywood, which is made with urea-formaldehyde resins. I am less sanguine about other engineered wood products, particularly particle board and oriented strand board (OSB), both because of off-gassing problems and because of concerns about their performance when left damp for long periods.

Building Envelope Materials

Replacing the exterior wooden shingles on my house was an environmental disappointment. At first, we removed only the minimum number of shingles necessary to replace the old windows. I tried to salvage the best of them for reuse, but they turned out to be too old and brittle. Later, the shingle subcontractor revised his quote and recommended replacing all the shingles on the addition rather than patching. He special-ordered two pallets of extralong cedar shingles to match the old ones.

The roof also was somewhat of an environmental disappointment. My initial research pointed toward cement shingles or corrugated cement panels as good roofing choices, as I found that cement is durable, fire resistant, made from plentiful materials, and environmentally nonreactive. Although cement production contributes 5% to global warming gasses, if one compares it to other options and factor in energy gains and losses, as well as roof color, it may be a better choice. Possibly, I gave in too easily, but I accepted my roofer's recommendation not to use slippery cement shingles on my 7.12 pitched roof. We used the ubiquitous asphalt shingles, although we chose the more durable fiberglass rather than organic felt ones.

Later on, as part of the PV system installation, I replaced the built-up tar-and-gravel roof asphalt on the main part of the house with a metal roof. I chose metal for its longevity, recyclability, ease of maintenance, and pleasing appearance, and because it came with integral PV panels.

I chose double-glazed, argon-filled, wooden casement windows with low-e coatings, an NFRC rating of 100, a U-factor of 0.47, insulating glazing, and clear glass. During installation, the window openings were flashed with building paper wrapped around jambs and over sills, and lapped to shed water. The carpenters then ran a continuous bead of sealant around the window frame fin. After setting the window in place, they applied another continuous bead of silicone sealant where the window frame abutted the wall. Finally, they installed galvanized sheet-metal "Z" flashing as a drip edge at the window head, and lapped building paper over the top edge of the "Z" flashing.

I wish I had been more innovative with insulation choices, but time, energy, and money wore thin. For example, I would have liked to try cotton batt insulation. This material has an R-value similar to that of fiberglass insulation, and is made mostly (95%) of recycled cotton fiber from denim manufacturing. It has none of the health hazards associated with fiberglass installation and is sometimes suggested for chemically sensitive individuals, but because of fire concerns, it is not available in all locales. My contractor surfed the Internet and found no sources west of the Mississippi for cotton batt insulation.

Another concern I had regarding insulation was how easily it could be installed. Cellulose insulation sounds very promising because it provides a good air seal. However, my contractor lacked the necessary training and equipment and did not want to have to schedule another subcontractor. Therefore, we used standard fiberglass batt insulation for the walls (R-11) and ceilings (R-30), and my testrun for cellulose insulation remains in the future.

We were somewhat innovative with foundation insulation. I had specified polystyrene boards to line the inside foundation walls and the ground in my newly excavated crawlspace. Randy worried about termites tunneling through the polystyrene en route to the wood framing. We found no acceptable alternate rigid insulation--other rigid insulations seemed relatively toxic (polyisocyanurates), were unsuitable for ground contact (perlite-fiber boards), or were not readily available. However, we did strike a bargain with a roofing supply company who had an unclaimed order of a product consisting of 2-inch polystyrene laminated to 1/2-inch cement board. Although cement board is not in itself a termite barrier, we deemed that--because the crawlspace was well protected from moisture, had good wood/dirt separation, and permitted easy monitoring of any termite tunnels between the polystyrene and the wood--the termite risk was low.

We installed the cement boards polystyrene side down over well-lapped sheets of a polyethylene moisture barrier. The cement board protects the polystyrene from damage, supports the layer of concrete rubble that we would later move in, and itself contributes to the thermal mass to store daily heat gains for later release into the crawlspace during cooler evenings (remember that the foundation is insulated, but the floor is not). The floor over the renovated addition does feel warmer than the floor over the main part of the house, so I think the attempt was useful.

Finish Materials

For the interior wood trim (baseboard, picture molding, windowsills, and door and window casing), I selected paint-grade finger-jointed pine or fir. I did not need a higher quality than paint grade, and the finger-jointed wood (made from short pieces of clear-grained wood, notched and glued end-to-end, and milled to selected profiles) seemed like a smart use of small trees and lumber mill waste. Randy ripped lengths of 1 1/4-inch-thick, finger-jointed doorjamb stock to obtain the extradeep windowsill profile that I wanted.

In my renovation, the flooring has attracted more admiration than any other finish material. The floors in the study and the 2nd floor bedroom (both are located in the addition) were 3/4-inch parquet-patterned hardwoods. They survived the renovation while protected under 1/8-inch plywood door skins, saving money, trees, and other resources and retaining an important aesthetic feature of the home.

In the new bathroom, entry hall, and pantry, I chose genuine linoleum for the floor. True linoleum, made from linseed oil and wood fiber that is pressure-cooked onto a jute backing, predates vinyl. It is advertised as "the 40-year floor" and, in its modern incarnation, comes in a variety of richly mottled tones. It costs more than most vinyls but less than many types of tile, stone, or hardwood flooring. It is easily installed and easily maintained, and at the end of its life span, it can be shredded for compost. I was able to find genuine linoleum from a local carpet and vinyl flooring supplier.

Much of my effort on this green renovation was spent on paint. As well as researching lead paint issues, I experimented with readily available commercial paints and did most of the interior painting myself. I did not have the time or interest to try out the all-natural or traditional paints made from plant or animal products (linseed oils, citrus oils, beeswax, milk, and so on). Nor did I look for sources of recycled paint (unused excess paint collected for reblending and repackaging), because of the color limitations on these paints and uncertainty about their VOC content.

I used very low- and zero- volatile organic compound (low-VOC) latex primer, flat, and semigloss paints for the interior walls, ceilings, and wood trim. These paints performed nicely, spread evenly, dried quickly, required minimum recoating, cleaned up easily, and were pleasant to work with. They were also expensive. The low-VOC paints, caulk, and sealants I used are another example of materials that are not only good for occupants but also worker-friendly. Very low- and zero-VOC paints are not available for exterior use unless one is willing to forego the usually added mildewcides and fungicides.

Utilities

Remaining categories for which I had to make product selections were plumbing, heating, and electrical work. For rough-in plumbing, Randy and I both had a bias against plastic piping. I dislike it because of the toxic off-gassing during its manufacture and useful life, as well as its relative inability to be recycled or easily disposed of. We did not use plastic piping except for the rainwater and storm drain system, and for this, we found 4" diameter PVC drainpipe from a salvage yard.

While connecting the water lines for the new bathroom, we found that my old galvanized steel pipes were suffering advanced arteriosclerosis. They were half clogged with rust and so brittle that they cracked when wrenched. I elected to replace them with copper for greater durability. We used type L piping, an upgrade from the standard type M. Local building performance specialist David Kibbey, in his Architectural Resource Guide, notes that type M has some lead content and recommends type L, which he says, "is safe and durable."

The plumbing fixtures that I chose were conventional, although (because of space limitations) they were the smallest I could find. I used a water-saving toilet (1.6 gallon/flush) and a low-flow showerhead. To meet local conservation ordinances, I also had to provide low-flow devices for the bathroom I was not otherwise renovating. I am satisfied with the low-flow fixtures' performance.

My old clothes washer and refrigerator have not yet reached the end of their life spans. Eventually, I would like to replace them with new energy-efficient models. My furnace, however, had reached the end of its life. I replaced it with a similar furnace with better efficiency--a Carrier Weathermaker 8000 58 WAV 070-00, with an annualized fuel utilization efficiency (AFUE) of 80%--and added R-4.2 FlexVent KP insulated ductwork.

While the walls were open during the renovation, I upgraded much of the old wiring. For the new lights in this area, I chose energy-efficient fluorescent fixtures for general lighting and halogen fixtures for wall sconces. I also replaced all of the light bulbs in the basement under the main house, as well as the most frequently used light bulbs in the main house, with compact fluorescent lamps (CFLs).

The CFLs are quite satisfactory. The light color and quality seem to match the old incandescents. They turn on instantaneously but require a few seconds to reach full intensity. The globular FLG17 bulbs and the thin tubular PL13s are bright enough, but their color and delay in start-up take getting used to. The halogen fixtures are slightly more efficient than incandescents--although much less efficient than fluorescents--and emit a warm, pleasant light. Because halogen fixtures can get hot enough to present a fire danger, though, they must be used with care and located only where flammables cannot contact them.

Looking Back

In the three years since I began this renovation, the world--or perhaps my perception of it--has changed. Green renovation seems to me no longer on the fringe. Today I know a community of designers and builders with expertise in sustainable design. I know of people with careers in promoting energy efficiency, building solar systems, or testing indoor air quality. Now I volunteer at Berkeley's new Green Resource Center--run by the local chapter of a national organization, Architects, Designers, and Planners for Social Responsibility--where people come to view green products or learn ways to become more eco-friendly.

The most important thing I've learned from this project is that there are building performance experts who should be consulted early in the design process of any renovation. Although I am satisfied with most of the architectural aspects of this renovation, I fell short on the energy issues. I've since learned that achieving energy efficiency in a building's normal operation is a best first step in "saving the earth."

In my renovation, I originally expected to leave the main part of my house, including the heating system, alone. I had assumed that the heat accumulated in the new solar chimney/light well could easily be blown into the existing furnace's return air supply. However, I didn't consult with any heating specialists until it was time to start the HVAC work. Learning that the old furnace was dead toward the end of the project left me little time, money, or interest to make good choices for energy efficiency. Therefore, I chose to vent the hot air from the lightwell into the insulated crawlspace.

I should also have sought out experienced solar installers instead of having my general contractor install the solar hot water system. An expert might have told me of the need for better freeze protection, even in this mild climate, and would have been available for troubleshooting and repairs when the need arose.

Since 1997, I've learned of other environmental issues that, in hindsight, I wish I had addressed. I wish I'd known that light-colored roofs help mitigate global warming before I chose my black roof shingles. I wish I'd known about dioxin's role as a hormone disrupter and carcinogen before I installed my PVC drainpipes. (Dioxin is a byproduct formed during the manufacture, use, and disposal of chlorine-containing plastics.) I wish I'd known how much cement manufacturing contributes to global warming before I'd detailed my extrathick concrete footing (or at least that I'd been able to get concrete with high fly ash content).

The reality, however, is that green renovation is a moving target. As we continue to learn, and as more and more of us select greener alternatives, green options become more available and even standard. We all vote with our pocketbooks. With what I've learned, I'll be able to make wiser green choices in maintaining my own home, and I'll be able to make better recommendations to my clients.

Pamela O'Malley Chang is a registered architect and licensed civil engineer in Berkeley, California.

For more information: Architectural Resource Guide, edited by David Kibbey and prepared by members of the Northern California chapter of Architects, Designers, and Planners for Social Responsibility, P.O. Box 9126, Berkeley, CA 94709. Tel:(510)273-2428; E-mail: adpsr@aol.com; Web site: www.adpsr-norcal.org.

Floor Plan, Before Renovation

Floor Plan, After Renovation

Figure 1. Most of the work in my renovation was done to the addition at the back of the house. Along with upgrading the foundation under this section, I changed the floor plan to incorporate a south-facing light well for passive-solar heat gain, and added windows. For the main part of the house, I just repainted during the renovation but later added a new roof and PV system.

Figure 2. There was a moderate but general downward trend in energy usage after the renovation. Some aberrations can be explained, such as high power use during construction and high gas use while learning the thermostat settings on the new furnace.

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