I’ll continue with the climate-focused case studies from the last installment soon. Right now, though, it’s worth giving a headsup on an upcoming conference event.
In the early days of Passive House in the United States, finding Passive House components – windows, HRVs, etc. – was a project in itself. How far we’ve come! In fact, if you’re interested in building your Passive Dream House, you’ll be able to find everything you need on the floor of the NESEA Building Energy 12 trade show floor.
The national conference of the venerable Northeast Sustainable Energy Association, every year BE12 astonishes. This year in Boston will be no different.
Passive House has been at the forefront of recent NESEA conferences. This year, to meet the growing appetite for all things Passive House, NESEA asked me to lead a tour of Passive House products that will be displayed at the NESEA trade show. (You’ll need to sign up for my Tuesday workshop to join the tour.) And so it will be my pleasure to guide the tour, to introduce them to the forward-thinking folks who’ve made available awesomely performing materials and components to the designers, builders and homeowners of Passive Houses. And made the components cost effective.
Some suppliers have been there for decades: Pioneers such as Stephen Thwaites with Thermotech Fiberglass Fenestration. I used Thermotech windows for the first time in the Smith House in Urbana, Ill. In 2002, it was the only North American window I could find that approached the Passive House specifications for the Urbana climate. Little did I know how dialed-in the window design by Stephen Thwaites really was. After 10 years of experience with Passive House construction throughout all different climate zones I have come to appreciate the smart balance applied in this design. A comparison of the energy balance of a certified European window and the Thermotech windows for my house showed that they were performing virtually equally, Thermotech maybe even a little better. How could that be at somewhat higher overall U-values? It is all about the right balance of Solar Heat Gain coefficient and U-value dialed into the specific climate conditions. Thinner frames to maximize the glass area in a high solar radiation climate is where the money is at. Passive House two thumbs up for an excellent North American manufactured fiberglass window perfectly designed for cold and sunny climates.
And then there is Pinnacle Window Solutions, with another classic, SeriousWindows. Serious has been used in many Passive Houses across the nation. It is a North American manufactured fiberglass window featuring excellent U-values well suited for cold and very cold climates. The solution of the suspended plastic film technology instead of an additional glass pane to increase the R-value allows the creation of a window that features essentially quadruple window performance, while maintaining a manageable weight. This is an interesting choice for the cold and very cold and perhaps more cloudy climates in North America. The high R of SeriousWindows comes at a price: the Solar Heat Gain Coefficient goes down the better the R and the visible transmittance is lowered as well. In cold climates with very good solar opportunities, a high Solar Heat Gain window with less R might perform just as well or better. This only reinforces what we have been teaching in the PHIUS trainings: the right window for the right climate. And Serious definitely has a place at the table.
In the last couple of years many entrepreneurs have brought new options for high-performance European Style windows. For example, Intus Windows has been turning heads with amazing Euro-style windows at very competitive prices (typically the Euro style window comes at a price). European Architectural Supply and New England Fenestration, LLC offer more European window varieties from other manufacturers such as Schueco, Macrowin and Unilux, all superb performing windows, all of them featuring thermally broken frames certified for the cool moderate climate through the Passivhaus Institut.
Go and visit — you have to see and touch these windows to understand the quality.
Windows are critical to Passive House construction, and so are systems components for minimized micro-load mechanical and ventilation systems. They put Passive House within economic reach. On this front, too, NESEA will also include many exhibitors. In addition, I’ll give a workshop at NESEA on Tuesday on cost effective integrated mechanical systems for North American climates.
In the early days, I would begin designing Passive House projects by first sketching the continuous air tightness layer. Later that focus shifted slightly toward laying out the mechanical system and the duct system. I am in love with Passive House mechanical systems simply because I never dreamed of being able to design it myself, and being able to really integrate it into the design process. They are in their own right very elegant and if well done one the key quality indicator of a Passive House. Hence, Passive House homeowners are actually proud to show off their mechanical rooms.
My latest interest has shifted towards heat pump hot water heaters as viable Passive House solutions, even in cold climates. Stiebel Eltron, Inc. makes such an appliance. It is a true super-insulated tank a Passive House enthusiast dreams of. Our Passive House builder, who installed it in our last project, was blown away in terms of efficiency and quality. By far the most energy efficient solution on the market, the unit is slightly more expensive than other options, but a good value. Another Passive House two thumbs up. Heat pump hot water heaters are becoming a very interesting solution for integrated mechanical systems designs for Passive Houses. Located inside the thermal envelop in a super low load home (including cooling and latent loads) the contributions to cooling and dehumidification by a heat pump hot water heater can be significantly helpful and in some cases all it takes.
And then there are the mini-split heat pumps. NESEA attracted two significant Passive House players, Daikin AC Americas, Inc. and Mitsubishi Electric HVAC. The mini-split systems are quickly becoming the most popular heating/cooling and dehumidification systems for Passive Homes. Daikin and Mitsubishi are among the manufacturers offering a heat pump slim duct built-in option. The units can be obtained in small sizes for single-zone and multi-zone systems (just what we need for Passive Homes) starting at 6k BTU/h and up. They generally have very good SEER ratings, the slim ducted options have a little lower rating, but are still solid in cold and mixed humid climates with larger cooling and dehumidification loads where integrating the space conditioning in the ventilation system is preferred.
Another interesting product from Daikin is the point source “Quaternity” Heat Pump wall mount unit. The SEER rating is 26.1 and it has an additional feature for warm humid climates where dehumidification might be needed when there is no cooling need: a dehumidification mode only. This unit is available in three capacities, 9k, 12k and 15k BTU/h. The Mitsubishi’s wall units have one of the best SEER ratings (26) and operate down to very low temperatures, making it appropriate for cold and very cold climates.
Mitsubishi has also truly excelled in terms of control of its heat pumps. Recently Mitsubishi introduced wireless technology eliminating the need to run wires and offering a centrally located thermostat just the way we like it.
Wagner Solar Inc and Tarm Biomass offer extremely low source energy heating options for multi-family Passive House projects (we are seeing more and more coming into the certification process). One major challenge of the multi-family typology is meeting the source energy criteria. Both companies sell wood and pellet boilers that offer excellent low carbon heating systems options. One boiler can be used for an entire medium-sized apartment complex if combined with Passive Solar. The Tarm Biomass boilers range from 75-80% efficiency for wood, 85-87% for pellets. Wagner Solar Inc offers a Pellet boiler with the efficiency of up to 93%. Smaller units for single family are available in Europe in combination with a hot water heat exchanger. It’s worth checking on availability of these systems. They are fine low source energy solutions for cold climates with predominantly heating requirements and lots of wood.
475 High Performance Building Supply is bridging the gap with many products not only in regards to air tightness but also over into the ventilation system realm. This Brooklyn, NY-based outfit has an interesting suite of specialty products mainly imported from Europe. They offer airtightness solutions from INTELLO plus and Pro Clima, a wood fiber sheathing/insulation product from Gutex, triple pane skylights from Fakro, and Foamglass from Pittsburgh Corning. They offer a through-wall decentralized apartment venting solution with a ceramic heat recovery core from Lunos and a compact heat pump by a Swedish company Nilan (not available yet but in testing – coming by year-end according to 475). The configuration is cost effective for cities, as it saves a lot of space by comprising all the mechanical functions of a Passive House into one compact box the size of a refrigerator.
Another high performance ventilator on the NESEA floor is Zehnder America, Inc.; it’s still the only game in town on this show floor in terms of high efficiency heat recovery ventilation. As important as high efficiency heat recovery ventilation is to Passive Houses, we still hope for a little more competition and for the North American ventilation system manufacturers to come up to speed. In the ventilation systems by Zehnder — integrated solutions for pre-warming the incoming air through ground source heat exchange and fast flex ducting systems – continue to impress. New this year: it received the Home Ventilation Institute Testing stamp of approval. The results show the heat recovery efficiency of this HRV under this testing protocol coming in second with 93% Apparent Sensible Effectiveness (ASE) which is topped by only one other ventilator made and sold in America, the UltimateAir RecoupeAerator with 95%. Zehnder products are a little pricy, but with the ease and time savings of installation and an impeccable maintenance record, it seems a well worth investment.
That’s it for part one of the tour…here’s part two, where we get into some more airtightness and wall system products.