On a busy street in a secluded neighborhood along the Alexandria metro line is this 1940 semi-attached row house. The owners of the property wanted the energy systems upgraded while preserving the grace and timeliness of this cottage style home.
“Please make our house more energy efficient and can you build us an addition on the back?”
The Energy House Team took on the challenge and went to work. The existing home had been well maintained and expertly renovated by their son 10 years ago. While the renovation was well done at that period of time but since then systems have aged that many things have changed in energy efficiency.
All new construction for the new addition. This 900 sf rear area was intended to expand the existing home to include a screened in porch in the basement, a family room off the kitchen for family gatherings and a study and master bedroom bath attached to the rear master bedroom to provide a suite arrangement for the owner’s private space.
The new addition has been designed to an Energy Star standard, which is higher than the building code in Alexandria. This includes advanced framing, with 2 x 6 framing, 24 inches on center to reduce thermal braiding as well as saving building materials and labor costs. Advanced framing includes California corners that enable Insulation deep into the corners of the framing. Insulated headers above exterior doors and windows to also reduce thermal bridging.
Energy savings with advanced framing is estimated at 15 to 18%
Huber Zip Board Insulated Sheathing – roof and exterior walls. Better known as Green Board this is one of the best systems for energy efficiency savings that we have available in the industry today. It does not provide the greatest energy savings but using Zip Board pull all the pieces together. It helps reduce thermal bridging, it waterproofs and helps air seal the entire structure.
Energy savings using Zip Board is estimated at 5 to 8%
Energy Star Anderson windows and doors. Installed to Energy Star Standards to ensure air sealing and water -proofing. Some of these quality windows will be upgraded to include laminated Lexan glass to reduce sound transfer from the City.
Energy savings using Anderson windows is estimated 5 to 8%
Heating and cooling for the new addition is a multi-zone mini-split unit which is one of the most energy -efficient systems in the marketplace. This design will offer four individual zones, WIFI controls together with heating, cooling, and dehumidification.
Energy savings using mini split unit is estimated to be 35%
Water savings devices will be incorporated into the master bath which will include dual flush toilet, instant hot water, and reduced water flow fixtures.
Water savings devices estimated to reduce water usage 20%
Insulation, which is the best bang for the money invested is designed be advanced above Code requirement. R25 Dense Packed Green Fiber cellulose in all exterior walls. R38 open cell foam in the first floor. R49 Green Fiber Insulation in the attic. Weatherization and air sealing included in Insulation methods.
Advanced Insulation estimated energy savings 15 to 20%
Overview – This 1940 style semi-attached townhouse is an existing structure. It contains three bedrooms upstairs and a bath, a kitchen, living room, dining room and powder room on the first floor and a finished basement with playroom, full bath and laundry room in the lower level. The building is brick with block framed, with plaster ceilings and walls throughout. The living room has a real wood burning fireplace as well as built-ins and hardwood floors throughout.
Heating & Cooling – The existing system was a gas boiler, located in the basement, for heating hot water for the radiator system throughout the Main house. This system has been replaced with a gas NAVIEN hot water system for operating the radiators as well as providing instant hot water for the home. The 80 gal hot water tank was also removed.
The cooling for the Main house was provided separately with a UNICO system located in the attic. This only provided air conditioning as it was only added in the renovation of the space 10 years ago. This system was replaced and upgraded to do both the base heating and cooling for the entire Main house. The gas NAVIEN system is only there as a backup for when the temperatures get extremely cold and the UNICO system is not capable of keeping up with the homes demands in just the worst times of the winter. The purpose of this switch was to reduce the carbon footprint of the home by using less gas and more electric than the owner hoped could be offset with solar panels on their roof.
Energy savings with new heating & cooling as well as hot water in the Main house is estimated to be 45%
Insulation – In areas of the house that the work was done added insulation was added to the attic area to bring it to an R49 with blown in Greenfiber cellulose. In the kitchen and bathroom areas, where the wall was opened for renovation, closed cell foam was added to increase insulation in that area to an R15. Weatherization and air sealing were also done in all areas of the Main home that were accessible during the renovation process. Exterior walls that had no insulation in them were left alone unless work was being done in that area. The economic cost of adding insulation throughout the house and the additional renovation cost for the plaster and new drywall did not make sense.
Energy savings with new insulation in the attic & some areas of the Main house are estimated to be 20%
LED Lighting – Throughout the house, all the existing lighting was switched to LED. The entire new addition was built to only include LED lighting.
Energy savings with new LED lighting in the Main house is estimated to be 75%
Windows – All new Andersen replacement windows are to be installed throughout the Main house. These windows are well insulated and will be installed to an Energy Star standard.
Energy saving with new Andersen windows plus proper install is estimated to be 5%
Overall – While a full renovation was not needed and therefore on the Main house the amounts of energy saved through the project are projected to be approximately 75%. It is the goal of the project to make up that remaining energy demand with a photovoltaics on the roof. Energy monitoring will be installed in this project to watch the actual energy usage against the past utility expenses.
Smart Technologies – Installed Ecobee programmable WIFI thermostat for the operation of both the NAVIEN and UNICO systems. In addition, a new hardwired smoke detector system, a rear backyard camera, and an Alexa home assistant will be installed in the home. An Equage will be used for the properties energy monitoring and solar production.
Architect – SB Design Studios Founder & Owner – Salvatore Benvenga. For more information visit www.sbdesignstudios.com.
General Contractor – James Smith Contracting.
- Energy savings with advanced framing is estimated at 15 to 18%
- Energy savings using Zip Board is estimated at 5 to 8%
- Energy savings using Anderson windows is estimated 5 to 8%
- Energy savings using mini split unit is estimated to be 35%
- Water savings devices estimated to reduce water usage 20%
- Advanced Insulation estimated energy savings 15 to 20%
- Energy savings with new heating & cooling as well as hot water in the Main house is estimated to be 45%
- Energy savings with new insulation in the attic & some areas of the Main house are estimated to be 20%
- Energy savings with new LED lighting in the Main house is estimated to be 75%
- Energy saving with new Andersen windows plus proper install is estimated to be 5%