HERS Rater and Energy Consultant:
Peter Harding
Home Energy Technologies LLC
The Middle Beach Residence is a 4300 sq ft residence with an additional 330 sq ft of conditioned basement space. It sits within a dense shoreline community with views to the Sound. The home has 6 bedrooms which are designed to accommodate the influx of guests and family during the summer and holidays. We have designed the conditioned space into several zones, separated by interior insulation, allowing it to close down to a 3000 sq ft core for times when the house is not in full use. Our client is interested in minimizing the homes impact on the environment by minimizing energy usage within the design and then offsetting this with on site renewable generation.
With the harsh shoreline environment, designing the envelope to manage the inevitable moisture while minimizing losses and infiltration is the most important element of the design. We have chosen to use traditional 2x6 framing in order to accommodate our structural requirements and steel superstructure. We are using Demilec® Agribalance® open cell foam to fill this cavity. Outside of the structural sheathing we are using 2" of expanded polystyrene foam to make a continuous, unbridged envelope. This moves the condensation point of the wall system outside of the wood structural systems and still allows the system to breath to the inside and outside. The wall system is achieving a very tight R-30 average wall envelope around the whole home. Over the exterior insulation we are using an OSB sheathing layer and a ¼" rain screen mesh with FSC white cedar shingles and Cellular PVC trim making a durable enclosure. The windows and doors will use high efficiency units with orientation specific glazing. Through overhangs and low E coatings, we are designing to maximize passive winter gain, while minimizing summer gain.
On the roof we are using standing seam copper with integrated PV film by Unisolar, which maintains the cottage aesthetics while capturing the south facing solar exposure. This is combined with a solar thermal system from Dawn Solar, which utilizes tubing under the metal roofing to collect solar radiation. This allows the solar heat energy of the south roof to be discretely harvested, while having the benefit of cooling the PV system. We are using spray foam to fully encapsulate the roof rafters to prevent bridging and keep our HVAC systems inside the envelope, achieving an average r-value of 45 for all of the ceiling systems.
The mechanical systems for the home are looking to be integrated to maximize their benefits during the various seasons and needs. We have added traditional PV panels to the garage roof which are more subtle from the street, bringing the total PV generation on the site to 9.6 KW. The solar thermal system generates about 120,000 BTU/ day, sized to address all of the domestic hot water needs during the summer months. The central HVAC system will be a closed loop ground source heat pump sized and zoned to maximize efficiency. We are looking to use Waterfurnace® Envision™ units which are some of the most efficient systems on the market. We are proposing a desuperheater to provide domestic hot water when the system is running, supplemented by the solar thermal system. During the winter months, when the geothermal system will provide most of the domestic hot water, heat from the solar thermal system will be used to preheat ground water to the geothermal system. We are also exploring an interior heat pump system which will generate cooling for a wine cellar and dehumidification for the basement systems, while putting the waste heat from the condenser into the domestic hot water storage. To further minimize energy usage within the house, we are using LED recessed fixtures throughout, with CFL compatible decorative fixtures wherever possible.
After meeting our client’s program needs, we first maximize the efficiency of the home through passive design and thoughtful envelope detailing. We then employ advanced green technologies to provide comfort, efficiency and on-site energy production in an architecturally integrated way.
Connecticut’s Energy Efficiency Programs are funded by a charge on customer energy bills.
The Programs are designed to help customers manage their energy usage and cost.
