Net Zero Home Builder

Net Zero Homes: Efficient, Comfortable, Durable

A Net Zero Energy Home is a high-performance home so energy efficient it can offset all or most annual energy consumption with renewable energy. What you'll get with a net zero build is a comfortable and healthful home with ultra-low or no utility bills. These homes, which exceed current building code requirements, are being designed and built with building science knowledge and methods refined over many years.

Because net zero building is done with great attention to detail and full consideration of air, moisture and energy movement, be sure to hire a qualified builder. See the case study below to see a net zero home built by Casaceli Construction. As members of the Northeast Sustainable Energy Association, we have excellent knowledge of this field. Combined with our track record as a quality home builder with many years of experience, you can trust us to deliver a well-planned and executed net zero home.

Net Zero Design


Whether you are building Colonial style, Craftsman, Modern or something in between, your home should fit your family's lifestyle and should be comfortable, healthful, energy efficient and durable.

Your net zero home will start with a great design which matches your lifestyle and integrates well with your building site.

The Building Shell

A high performance thermal shell will incorporate high performance windows, insulation and draft protection and be installed with full attention to moisture and air control. Whole house water protection will keep the house dry by design and control interior moisture.

Heating & Cooling

Your high performance thermal shell will reduce heating and cooling building loads and allow for the installation a high performance heating and cooling system. We will use proven techniques such as keeping duct work inside the thermal shell to eliminate wasted energy.

Efficient Systems

Use of high efficiency LED lighting, appliances, exhaust fans and domestic water heating systems will further lower the energy demand load. Domestic hot water production will be located close to its points of use and may be coupled with an efficient delivery system which will minimize hot water delivery time and wasted energy.

A Healthful Home

The use of Low VOC products and components is just the start of your healthful home. Your high performance super sealed shell pays back in dividends. Rodents and insects have no open paths to your family. Fresh air from outside the home is brought in, filtered and delivered throughout the house through clean air ducts.

Compare this to a conventional home:
In the 'old' conventional house an intake only fan drawing 'fresh' air in through all the unsealed holes left behind by haphazard sealing and construction, air which is likely being filtered through unsealed wall cavities accessible to rodents and insects.

Renewable Energy

Energy from the sun is free and renewable and most commonly used for completing the net zero equation. The home design will make provision for harnessing solar energy by positioning available space to optimize production and by making sure the structure will support a solar array and provide pathways for wiring and equipment.

Case Study: Net Zero Home in Marlborough, MA

The following are pictures of a net zero energy house we built in 2015-2016 showing a few net zero construction details.

Concrete Footer for Net Zero Home.

Concrete footing sprayed with foundation sealer.

  1. Footing is placed on top of a layer of crushed stone which contains a foundation drain tied to the city storm drain system. This decouples the footing from ground water and moist soil below the footing.
  2. The black is a layer of asphalt foundation sealer which acts as a capillary break and prevents moisture from wicking up through the concrete foundation walls.
  3. The white pipe peeking through the stone is a passive radon gas collection system which vents out through the roof.
Concrete Foundation Wall with Waterproofing.

Concrete foundation wall with waterproofing system.

Waterproofing applied to foundation wall exterior with a layer of recycled rubber padding serving two functions.

  1. First, it protects waterproofing layer from backfill operations.
  2. Second, it acts as a path for ground or surface water to drain down and into foundation drain. Water follows path of least resistance and drains down and away and not into the foundation.
Insulation Below Cellar Floor.

R-22 Insulation below cellar floor is the start of whole house thermal break. 

  1. A thermal break eliminates substantial energy loss that can occur through highly conductive construction materials such as wood studs and concrete walls/slabs by putting a high R value material between those components and the unconditioned house exterior.
  2. Two layers of 2" rigid insulation for a total R-22 under slab.
  3. One layer of 2" rigid insulation at concrete floor perimeter for thermal break between concrete slab and foundation wall.
Rigid Roof Insulation for Net Zero Home.

Roof assembly. 

  1. Three layers of poly iso rigid insulation for a total of 5 ½" of rigid insulation couple with 11 ½" of blown in cellulose in rafter bays (not seen in photo) for an R-76 roof assembly.
  2. Air barrier-continuous over entire wood frame starting at foundation.
Sealed Pipe Penetrations.

Rear house wall showing sealed pipe penetrations for HVAC equipment.

  1. Air barrier sealed to concrete foundation with Siga tape and concrete bonding agent.
  2. Sealed penetrations through the high-performance thermal shell.
  3. Penetration seals were not left to chance. Installing penetrations through the thermal shell were pulled from mechanical, electrical and plumbing contracts and installed by our crew.
  4. Air barriers are critical for stopping vapor from being transported into wall and roof assemblies as "vapor is principally transported by air flow and not by vapor diffusion." Joseph Lstiburek BSI-084: Forty Years of Air Barriers*-The Evolution of the Residential Air Barrier.
Wall With Window Bucks.

Wall with window bucks.

  1. Air barrier-continuous over entire wood frame.
  2. Plywood window bucks sealed to air barrier with urethane caulk.
  3. Two layers of 2" rigid insulation with staggered joints on exterior of 2 x 6 walls with blown in cellulose for a total wall assembly R-42. The rigid insulation with taped seams is the weather resistant barrier and also acts to move the dew point of the wall to out beyond the air barrier instead of the inside of the exterior sheathing as the case may be with walls well insulated with interior insulation and no exterior insulation.
Fully Insulated Exterior for Net Zero Home.

Fully insulated exterior and partial siding installation.

  1. Rigid insulation with tape joints as weather resistant barrier.
  2. Furring strips hung vertically to carry siding and creating a drainage plain. Any water making it way behind the siding will drop easily down the ¾" spacing between the siding and the weather resistant barrier (WRB).  The air space allows residual moisture to dry quickly.  The front porch and rear entry landing are supported independently of the house frame.  This means there is no WRB penetration at the front porch or back entry landing floor at a critical deck/house connection which is so often a problem area for flashing on conventionally built homes.