European Inspired Mountain Chalet

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European Inspired Mountain Chalet-summer exteriorWhile traveling in the French and Swiss Alps, the owners of this European inspired mountain chalet became captivated by the rustic charm of the over 200-year-old chalets they had seen there. They perused numerous books about chalet design, becoming both well informed and even more enthusiastic with the building style. Working with architect Paul Robert Rousselle of Stowe and Steve Sisler of Sisler Builders, they incorporated design cues from traditional chalet construction, their own carefully cultivated theme ideas, and state-of-the-art energy usage desires to bring their unique European inspired mountain chalet to fruition for the 21st century and beyond.

European Inspired Chalet-north side windowsThe couple and their three children, ages 13, 18, and 20, are originally from Long Island. They moved to Stowe for its quality of life, easy access to sports, and the outdoor activities they enjoy. They rented a home while beginning the process of designing their house, finding an architect, and deciding on a builder. After meeting with Steve and checking with a variety of reference sources they chose Sisler Builders. Steve had done similar chalet-style construction, and they felt that besides his reputation for perfection and integrity, he and his team were well suited for the job. They also knew that Sisler Builders is committed to building highly energy efficient homes, a priority for them.

European Inspired Chalet-living roomEuropean Inspired Chalet-dining room view

Beyond being committed to the chalet aesthetic, the couple’s primary objectives were an open and functional layout, natural flow, and ease of use. They wanted to maintain a timeless look, so the house never felt dated. They also wanted to take advantage of the fantastic sloping site, situating the house so that it made the most of the jaw-dropping views of Stowe’s ski trails. The floor-to-ceiling windows all across the main living areas did the trick for this last desire!

“There was a lot of collaboration during the building process,” said the husband. “Every square inch of the house was discussed with the architect and builder, weighing all factors of design, engineering, and the actual building process.”

Energy efficiency

The nearly 4,500-square-foot structure is extremely air tight and energy efficient. It is heated with geothermal wells connected to electric heat pumps, which are partially powered by photovoltaic (PV) solar panels. A wood stove, cleverly connected to duct work that is part of the air conditioning system, allows heat to be distributed throughout the home, instead of being concentrated to the area close to the woodstove. The structure tested out at 0.82 ACH50, which means it has a nearly Passive House air exchange level, and is remarkably air tight. It has radiant heat tubing embedded in the concrete slabs of both the lower and first floor levels. This is a well-thought-out system, as the heat pumps can readily produce water at just the proper temperature for optimal radiant heating. With the exceedingly low natural air-exchange rate, a mechanical heat recovery air exchange system was mandatory.

Sisler Builders optimized the amount of insulation installed by computer modeling the front-end cost of different thicknesses of insulation versus the operating cost associated with those thicknesses. With this proper engineering and holistic mechanical system approach, the owners have found that the wood stove heats the entire house, and are ecstatic about the inexpensive heating costs and comfort they feel year round.

European Inspired Chalet-dining room European Inspired Chalet-bedroom

Staying local

European Inspired Chalet-kitchenLocally sourced materials strongly influenced the house design. A significant contributor to its look and feel was the use of native hemlock beams and paneling that were procured and milled nearby. Sisler Builders took special care to purchase and sequence their installation in order to facilitate proper drying of the wood. The wife’s favorite aspect of the interior is the mix of rustic and modern design themes throughout the house, which were achieved with materials such as the native hemlock beams juxtaposed with refined tile and crisp sheetrock detailing, finished in striking colors.

The husband’s favorite aspect is the kitchen, which he says is the house’s focal point. “I like to cook. I wanted a kitchen that is functional. We put a lot of thought into multiple work stations and the layout works well for us. I like all the systems and finishes we integrated.”

European Inspired Chalet-winter exteriorThe owners would have preferred to take a year up front to flesh out the house’s design, but they did not have that luxury, so decisions were made almost daily during the building process. “The project manager, Matt Rouleau was brilliant,” the husband said. “He coordinated everything and it was a pleasure working with him. He is extraordinary. Our experience with Sisler Builders has been great. They stood behind everything they did and we continue to have good relationships with Steve and Matt and all the carpenters and subcontractors we met through the process. We’re very happy with our Vermont chalet.”

European Inspired Chalet-aerial

What is ACH50? All You Need to Know is Right Here

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The last five houses that Sisler Builders completed have all tested with ACH50 less than .85. But what does that mean? What is ACH50? Get ready for some physics!

What is ACH50?What is ACH50?

ACH50 is the abbreviation for air changes per hour at 50 pascals (Pa) pressure differential. It is how we measure the energy efficiency of a house. It is the number of times the air volume in a building changes per hour at 50 Pa of pressure. During a blower door test we depressurize a building to negative 50 Pa pressure, with regard to the outside air pressure. We accomplish this by continuously exhausting a measured volume of air from the building with the blower door, while simultaneously measuring the pressure differential from inside to out. We adjust the bower until we reach our target pressure differential of negative 50 Pa, and then record the volume of air being exhausted to accomplish this in cubic feet per minute (CFM). This measurement is called the CFM50 of the building and quantifies the air leakage of the structure being tested. The higher the CFM50, the leakier the building.

What is ACH50?CFM50 is the building performance standard used almost universally to quantify building air leakage, but it is not a very useful number for evaluating how “tight or leaky” a building is, unless we know a little more about the structure. For example, a giant warehouse may be quite tight, but have a high CFM50 compared to a small house that is quite leaky, because of the enormous discrepancy in the volumes of the two buildings. In order to compare the relative “leakiness” of separate buildings we need to account for this potential difference in structures’ volumes. To do this we use both the CFM50 and volume to calculate what is called the ACH50 – air changes per hour at 50 Pa pressure differential – of the structure. This number indicates the number of times in one hour the total volume of air in the entire building will be exhausted through the blower door when it is maintaining -50 Pa pressure differential with regard to the outside air pressure.

The CFM50 tells us how many cubic feet of air are being exhausted from a building every minute to reach -50 Pa. To calculate ACH50 values we multiply the CFM50 number by 60 minutes per hour to determine how many cubic feet per hour are being exhausted. Now we divide this product by the total volume of the building in cubic feet and we know how many times this volume will be exhausted in on hour at this pressure. Voila. The ACH50 values!

A building’s ACH50 number indicates how tightly a building was originally constructed (or later air-sealed) and is an excellent gauge for comparing leakiness between buildings. The lower the ACH50 values, the tighter the building. Vermont’s residential energy code currently requires new houses to have an ACH50 of 3.0 or less. By comparison, many older houses we’ve tested have ACH50 numbers of 10 or more, and some have been much, much higher. Today’s high-performance houses typically have ACH50s closer to 1.0.  The last five houses that Sisler Builders completed all have ACH50 of less than 0.85.

Air Source Heat Pumps – Renewable Resource Heating

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Air source heat pumps and ground source heat pumps are gaining a foothold in the construction industry for their energy efficiency and cost effectiveness. For decades, Sisler Builders installed propane (and sometimes oil) heating equipment as a matter of course. The advent of heat-pump technology and, to a lesser extent, rising fuel prices, has changed all of that.

For the last few years, Sisler Builders installed air source or ground source heat pumps in almost all of their buildings. The technology for heat pumps, which are essentially air conditioners that run in reverse, has improved drastically in the last 20 years. On average, the systems are now four times more efficient than traditional electric resistance heat, operate well (even in Vermont winters) and cost less to operate than propane or oil.

In 2013 Sisler Builders installed air source heat pumps in one of their apartment buildings in Waterbury, Vermont. It replaced an old and outdated oil boiler. The annual heating and hot water costs of the building have gone from about $8,000 to $2,500 annually! And, since almost all of the electricity comes from a rooftop solar array, the system is much better for the environment, too.

To learn more about air source and ground source heat pumps, go to GreenBuildingAdvisor.com and search for Nick Sisler. Nick is co-founder and lead engineer at Ekotrope, a building energy software and consulting company. This essay is adapted from an article in Green Building Advisor.

Two Energy Efficient Vermont Homes

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Here is an up-close look at two energy efficient Vermont homes built by Sisler Builders in Stowe, Vermont.

Ernie Ruskey and Laurie Wood had three primary objectives when they built their house in Morrisville: simplicity, energy efficiency, and harmony with the site. They achieved their goals with a minimalist modern design, a home that is super tight, has excellent air exchange rate results, and heats easily with propane and supplemental wood. The house is nestled on a gentle, wooded hillside, with mountains views to the west, and blends unobtrusively with its surroundings.

energy efficient vermont homes  energy efficient vermont homes

energy efficient vermont homes“One goal in all of our work is to have a house that fits into the site and landscape. It’s always about the view and topography,” says Ernie, architect and owner of Tektonika Studio Architects in Stowe. He designed their house, which has a wedge shape that is, shall we say, wedged into the site’s natural topography. The garage is a half-story down, connected by an open, covered walkway leading to the staircase and main entry. Passing through the mudroom and kitchen to the light-filled great room you notice the subtle widening of the space. In consort with the nine-foot ceilings, expansive west-facing windows, well detailed maple stairwell, and natural stone hearth, this is a truly inviting space. A deck and screened porch off the wide end enable outdoor living close to nature.

energy efficient vermont homes  energy efficient vermont homes

As a Stowe architect, Ernie knows many local builders, and choosing one to build a house he designed for his family was a difficult decision. “I gave several builders a shot,” he says. “Sisler Builders was on the short list of three companies. Their bid was the middle number and it felt realistic. I also felt good about the company’s project-management skills and their deep energy-efficiency knowledge.

energy efficient vermont homesSisler Builders’ core tenet is building the tightest envelope possible at a cost that doesn’t break the budget. Their seven years of focused home energy analysis and retrofits has shown them where typical problems are, especially for air and heat leakage. Whether building a new house or an addition, their crews know what to do to make sure there are no egregious air leaks in places that are difficult, costly, or impossible to fix later.

energy efficient vermont homesAesthetics were also important for Ernie and Laurie. “Sisler Builders made the right matches with their subcontractors. The craftsmanship is superior and from a design standpoint it really worked for me,” Ernie explains. “The costing piece, team, scheduling, and experience are all important, but most important in any building process is a good rapport. Steve communicates well and our personalities clicked. Laurie and I both had, and have, a good feeling about him.”

 

Jo and Jonathan (JP) Poole of Concord, Mass., had similar goals when building their house in Stowe. Simplicity was their primary objective. They wanted a modern design, small enough to feel cozy, yet large enough to accommodate guests. They also wanted a house that was ecologically friendly and sustainable, which led them to a solar-powered geothermal heating and cooling system which uses only renewable resources.

energy efficient vermont homes  energy efficient vermont homes

When the Pooles moved from the United Kingdom to the United States, they first came to Stowe. They ended up in Concord, Mass., where JP works in biotech and Jo owns Concord Fitsquad. They continued visiting Stowe, and when it was time to build their house they reached out to Sisler Builders, whom they had heard about around town, particularly in the context of highly energy-efficient, ecologically friendly construction.

“We set up a meeting with Steve Sisler and liked his practical approach,” JP says. When it was time to find an architect, Steve recommended Ernie Ruskey of Tektonika Studio Architects. “Steve thought Ernie would be a good match for us. His tastes, design perspective, and core interests were aligned with ours.”

energy efficient vermont homes  energy efficient vermont homes

At both the Poole and Ruskey-Wood residences, Sisler Builders implemented a combination of recently introduced energy efficiency building products and practices. When building the envelopes they used Huber’s superior Zip-R wall-sheathing panel and proprietary tape. With careful application of the tape at all seams you can cost-effectively ensure a tight building envelope even before insulation is applied. Sisler Builders did that at both homes, achieving air exchange level’s really close to the rigorous Passive House Institute US best practice standards, and they did it cost effectively.

energy efficient vermont homesThe Poole house begins with the main-floor mudroom, which includes a huge, open-riser, three-story, steel-supported staircase. Beyond that is the heart of the home, a spacious and airy great room/kitchen/dining room. “The mud room and open-plan living area were primary for us. We focused our resources there and on the staircase,” JP notes.

The house is entirely electrically driven, with LED lighting throughout. Radiant heat is powered by a closed loop geothermal system supplemented with a modern Hearthstone soapstone wood stove. Their 4.9 kW solar array provides about 70 percent of all the electricity the home uses.

It’s the only modern style house in their neigh-borhood, yet it’s inconspicuous and unassuming. JP and Jo concur that at the end of the day they were really happy with the final product. “Steve quickly found solutions to challenges and was sensible and direct. Our house is simple and clean and that means the quality of work is extra important. Sisler Builders, their crew, and subcontractors provided excellent craftsmanship. It was a good team.”

Vermont Home Energy Audits

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One of the best ways for homeowners to reduce their carbon footprint starts with home energy audits. Within hours they learn how efficient their home is and what they can do to improve it. Another way is to build a home that meets or exceeds state energy efficiency standards.

Research has shown that housing accounts for approximately 40 percent of energy usage. If everyone took steps for making old and new homes more efficient, that number could be cut in half.

In 2010, when the country was reeling from the Great Recession, Sisler Builders created a division within their company that focuses on energy efficiency in current and future homes. “I’ve always been interested in making our building envelopes as tight as possible,” says president Steve Sisler. “I saw the energy efficiency training for my staff as a symbiotic benefit. We would learn methods to make our new home projects better, while learning how to enhance older homes. We were in a recession and this seemed to me an excellent alternative to layoffs.”

home energy auditsSisler Builder’s energy division has grown to include six employees. Mike D’Muhala is the technical and “science guy,” while Brian Irwin is the business manager and marketing director. A crew of four does home energy audits, installations, and retrofits. Since 2010 they have performed several hundred home energy audits, resulting in over 160 home and commercial energy retrofits. To date D’Muhala estimates that these customers have saved 16 billion BTUs and 109 thousand kilowatt hours of electricity. This equates to about a quarter million dollars in savings and a 2,000-ton reduction in CO2 emissions, roughly the same as removing 500 cars from the road for one year.

home energy audits“The most common problem we see when we do home energy audits is air leakage,” says D’Muhala. “We partner with Efficiency Vermont, and they will give a $1,000 rebate if a client reduces air leakage by 35 percent. This can be done primarily through blower door-assisted air sealing of the attic deck, basement, and living spaces.” Additional incentives are available for upgrading insulation and heating systems.

home energy auditsSisler Builders charges $450 for home energy audits and Efficiency Vermont gives an instant $100 rebate, so the cost to the customer is $350 for a typical house. D’Muhala conducts the audit, spending an average of three to four hours on site, inspecting and conducting tests. He uses a blower door, a machine that measures the air tightness of buildings, and a thermal camera to locate air leakage sites.

D’Muhala then puts together an energy model of the home which he uses to generate a list of recommendations including their costs, energy savings, and estimates of Efficiency Vermont rebates. This model can be tweaked to meet budget, lifestyle, and aesthetic preferences.

“If a house is already tight, we can still find ways to make it even tighter,” D’Muhala says. “Once a house is pretty tight it requires a heat recovery ventilator, which brings fresh air into the house through a heat exchanger. It’s all about ventilation. Send the stale, moist air out and bring the fresh air in.”

D’Muhala has been imparting the lessons he’s learned to the site supervisors and carpenters involved in Sisler Builders’ new home and significant remodel projects. The symbiotic relationship Steve Sisler was hoping for in 2010 has borne fruit! Of the six new homes they completed since 2012, all have exceeded the rigorous state-mandated testing amounts by at least 300 percent. One earned kudos from Efficiency Vermont Senior Energy Consultant TJ Holloway when he noted, “The air density (temperature) corrected blower door number is 509 CFM. This is really, really tight! Passive house tight.” This attention to detail results in reduced energy consumption, pollution, and maintenance coupled with increased interior comfort.

Sisler Builders is a member of Efficiency Vermont’s Home Performance with ENERGY STAR program and their Efficiency Excellence Network. To schedule an energy audit or for information about reducing your carbon footprint call Brian Irwin at Sisler Builders, 802-253-5672.

Heat Pump Technology – the Way of the Future

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Heat pump technologyNick Sisler believes that air-source heat pump technology is the way of the future. Sisler, co-founder and engineer at Ekotrope, is one of a growing number of experts in the energy, building, heating, and environmental fields. “By allowing us to heat with clean renewal energy generated by photovoltaics, wind turbines, or a hydro plant, electric heating will be an important and necessary step in cutting greenhouse gas emissions,” Sisler says.

Mike D’Muhala, energy division manager at Sisler Builders, is also on board with heat pump technology. Hearing him explain concepts like heat of vaporization, coefficient of performance, compression, joules, and absolute zero makes you wish you’d paid more attention in physics class. Even when the explanation is put in simple terms (“just an air conditioner running backwards” and “the same technology as a refrigerator”), it still feels like there must be magic involved in heating a home by extracting heat from cold outside air, even when it’s below zero.

Whether it’s physical or mystical, it’s economical: newer heat pump technology can provide much lower cost heating, cooling, short payback of investment, and lower carbon emissions.

A primer on heat pump technology

The Second Law of Thermodynamics shows that when two things of different temperatures approach each other, the hot thing cools and the cold thing heats up. This natural law has been used for cooling for decades, most notably in the form of refrigerators and air conditioners.

Essentially, an air source heat pump takes the heat out of ambient outside air (there is heat in outside air, even when it’s well below zero) by passing a chemical refrigerant though coils outside. As the liquid refrigerant heats, it becomes a vapor (just like boiling water). This hot vapor is then forced through a compressor (using electricity) to further raise its temperature. It is then pumped through coils inside the home, where the heat is released. As the vapor cools (releases its heat) it condenses back into liquid refrigerant, and the cycle repeats itself.

What’s new in heat pump technology?

For some time, ground source (geothermal) heat pumps have been transferring the nearly constant temperature of the earth into dwellings to heat and/or cool them. Often, though, installation costs for these systems can be high. In warmer climates, air source heat pumps have also been used effectively.

Now, thanks to technology improvements, better (and more environmentally benign) refrigerants, and – ironically – relatively low electricity prices, air source heat pumps are invading Vermont. In 2014, the Vermont legislature passed a bill that will have the state’s efficiency utility, Efficiency Vermont, consider reversing its traditional mission of reducing electricity consumption. As they state, “. . . in some instances, there is a strong economic and environmental case to be made for using more electricity, not less. Take the case of a modern air source heat pump. This efficient technology can help to heat a home at one-half to one-third the cost of heating systems that use propane or heating oil, while also providing significant greenhouse gas benefits.”

The benefits of air source heat pumps sometimes seem too good to be true. By one measure, called the Coefficient of Performance, air source heat pumps can provide three to five times more heat energy than they consume in electricity. Some heat pump evangelists are predicting that this efficiency will increase to 10 or more, and could revolutionize our energy future. Heat pumps also need not be just air-to-air. Air source systems are also able to heat domestic hot water, and may even integrate with or supplement traditional forced hot water heating systems. There is at least one electric utility in Vermont (Green Mountain Power) that, along with Efficiency Vermont, recognizes the value of heat pumps and is offering incentives or special rates to save even more money.

There are drawbacks, of course. Current heat pumps may not provide a whole-home heating solution. A drafty house also lowers the benefits. Performance declines as the temperature drops, and another heat source is needed for cold Vermont winters. Also, if electricity prices should increase dramatically, the economics would become less appealing.

Sisler Builders is embracing air source heat pumps, as they may fit within a custom home, and especially within their energy division. Mike D’Muhala is using his expertise and magic in providing efficiency audits and retrofits, and is including heat pump technology in the alchemy.

Dilapidated House Renovations

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For two years, Jennifer and Shawn Donovan of Waterbury Center had been scouring central Vermont for the right house to buy. After years of renting, they never thought finding an affordable house would be so difficult. Little did they know that dilapidated house renovations were in their future.

dilapidated house renovations  dilapidated house renovations

On a whim, Jen called builder Steve Sisler, owner of Sisler Builders. “Do you have any spec houses, property… anything?” she begged. In fact, Steve had something, but it was, well, not for everyone. “You want to look at a derelict building and see if it might work for you?” he replied. He made sure to note that it had great views of Camel’s Hump. Unfazed by the unusual proposition, Jen agreed to stop by the next day.

The two met in Waterbury Center in front of a dilapidated and forlorn looking old house with ugly green asbestos siding. Steve explained that Sisler Builders would begin the dilapidated house renovations by tearing down the house and building on the existing foundation. He wanted to recycle as much of the building materials as possible and build a green, energy-efficient home. Jen walked around the grungy site, her shoes crunching on broken glass. She was quiet, and told Steve she’d get back to him. Privately, she had fallen in love with the idea of renovating an old home on that site.

Dilapidated house renovations on a budget

Jen showed Shawn the house that weekend. He was skeptical, but intrigued by the ideas that Steve had proposed, and motivated by his wife’s enthusiasm. A few days later, they called Steve to say they were interested – with a catch: could he build their dream three-bedroom, two-bathroom house for $180,000?

“That will be a challenge,” Steve replied, “but we’re willing to accept it.” It would be the leanest construction budget for a house of this size that Sisler Builders had done in years. But Steve and his colleagues, led by site supervisor and carpenter Matt Rouleau, were eager to demonstrate that with creativity and experience, building state-of-the-art energy-efficient homes – their specialty – could be done on a budget and a tight time frame.

dilapidated house renovations  dilapidated house renovations  dilapidated house renovations

Steve, Matt, and their subcontractors came to the Donovans with numerous ideas for how to save money and energy while building something beautiful and practical from the dilapidated old house. By using the existing 20-year-old concrete foundation, deemed sound by a structural engineer, the couple could save $30,000. Steve and Matt proposed using T-111 siding instead of clapboards, for a savings of around $12,000.

Plumbing subcontractor Don Clark pointed out that an acid-etched concrete floor with radiant heat had the dual bonus of being more efficient and $2,000 cheaper than a hardwood floor. Electrician Mike Cannon proposed installing the electrical service in a way that saved significant costs. Noi Jones and Kevin Kinney got to work fabricating the central staircase using exposed old structural beams. A passive solar design featuring lots of glass would bring in light and views, and keep the home warm. Steve would design and draw the house plans himself, and Jen and Shawn offered to do their own painting and buy and install all the appliances and cabinets.

After making one minor change to the design, the couple “absolutely let us run with it,” recounts Steve. Five months after the dilapidated old house renovations began, Jen and Shawn Donovan moved into the beautiful new home that rose in its place.

Dream home completed

dilapidated house renovations  dilapidated house renovationsLight streams in through the numerous south-facing windows that extend from floor to ceiling. The distinctive profile of Camel’s Hump feels close enough to reach out and stroke. Warmth rises from the heated concrete floor. Weathered barn board from the old house forms an interesting corner, and a staircase in the center of the living room features hand-hewn century-old posts, railings made of peeled logs that were formerly rafters in the old schoolhouse, and stair treads cut from the original massive 8×8 beams. Old melds seamlessly with new.

dilapidated house renovations  dilapidated house renovations   dilapidated house renovations

Steve Sisler says the Donovan house has been especially satisfying for him, his subcontractors and his colleagues at Sisler Builders. “I’m proud that we took a derelict building that was a drag on the community and the tax base and turned it into something viable, valuable, and energy efficient for a young couple. They appreciate what it was, and what we made of it, and now have a real pride of place.” Steve reflects, “It’s rewarding to take something that was broken and make it beautiful.”