Walking the Talk: Transforming a house into a sustainable healthy home

E3 Innovate recently completed a renovation project on a home south of Nashville in the Green Hills area. The home was built in 2015 but one of the HVAC systems had already reached the end of its life and needed to be replaced. This prompted the homeowners to take action, after having gone through an entire summer without an HVAC system on their second floor! 

Since they knew they needed to replace an entire HVAC system, the homeowners took the opportunity to make durability and efficiency upgrades to their home as well, measure that would support their efforts to live a sustainable lifestyle. The family is very interested in doing their part for the environment and reducing their carbon footprint and they felt their home was an important piece of the equation. 

Below is a summary of the work that was completed to transform this house into a high performance, energy-efficient, healthy home:


Total HVAC Replacement and Re-Design


  • Improved efficiency
  • Improved indoor air quality
  • Improved comfort control
  • Improved humidity management

Originally, the first floor was served by a 5-TON packaged system. The duct system was fairly well sealed but had collected a fair amount of dust and debris over the last 7 years. The leaky shroud allowed the coils to build up with debris and mold (see image below). The homeowners wanted more control over temperature in their master bedroom, so E3 designed a plan to use two separate ducted high-efficiency Mitsubishi heat-pump systems for the first floor, one of which would serve the master area. 

Given that the second-floor unit had failed, E3 took the opportunity to redesign an improved duct system to go along with the new HVAC unit. The old duct work was strung along the roof rafters of the attic where it could pick up heat in the hot summer and loose heat in the cold winter. E3 removed an octopus-worth of duct lines and transitioned this attic space to an encapsulated attic using spray foam. The benefit of foaming the roof is that it brings all of the ductwork into a sealed and semi-temperate space. This helps improve efficiency and reduces household dust that comes in from tradition vented attics. A ducted high-efficiency Mitsubishi heat-pump system was also used in this area. New shorter duct lines were designed to reduce energy loss.

The fourth HVAC system was added to a new bonus room the homeowners added above the garage. More on that aspect of the project below! Because the space would have such a different need for heating and cooling than the rest of the house, it warranted its own Mitsubishi mini-split system. 


Before: The packaged system was caked with debris and he split system had failed. 

Dirty HVAC Coils on Package Unit                    Old split and packaged HVAC systems


The pre-existing HVAC system had ductwork running through the unconditioned attic


After: New Zone System using high-efficiency Mitshubishi heat pumps.

New ducted heat pump system                New zoned Mitsubishi systems



Attic Insulation and Upgrades


  • Improve efficiency
  • Reduce dust
  • Add functional storage space

Two areas of attic were upgraded.

The upper-most attic above the second floor was originally a vented attic insulated with blown cellulose. This was the area containing the ductwork octopus. To improve efficiency and air sealing, E3 spray foamed the roof deck and reworked the duct system to create shorter duct lines to reduce energy loss. 

The second attic knee wall area off the second-floor family room was improved with spray foam insulation and fire-proof paint so this space could be used as a weather-proof storage area. LED lighting was added, and a hidden Murphey door was installed that concealed the access point. 


Murphy door closed           Murphy door opens up into a protected attic storage space.


Encapsulated Crawlspace


  • Improved durability
  • Improved efficiency and comfort
  • Moisture management
  • Odor reduction
  • Radon mitigation 

The crawlspace was cleaned out and encapsulated with white laminate and spray foam to keep the underside of the home dry and tempered. There had been numerous water events in the crawlspace because some of the crawlspace vents were located below grade. 

Transitioning to a sealed crawlspace allows all of the vents to be permanently blocked and sealed, preventing water intrusion, moisture issues, and mold growth. A sealed crawlspace also allows the HVAC system and ductwork to stay cleaner. 

A designated dehumidifier is always added to an E3 crawlspace as an extra layer of moisture protection. This crawlspace was no different!

Before: The space had an issue with water intrusion, as many Nashville crawlspaces do.

Unsealed Crawlspace               


Water intrusion in the crawlspace              Foundation vents below grade allow water to enter crawlspace



After: A sealed crawlspace will protect the foundation of the home from moisture, pests, and heatloss. 

Encapsulated crawlspace


Fresh Air System


  • Improve freshness
  • Improve indoor air quality

To improve the air quality in the home, an ERV (energy recovery ventilator) was added to bring in fresh outdoor air and exhaust stale indoor air. An ERV system also helps to pre-condition the incoming air so it does not take as much energy to heat and cool. This keeps the house smelling fresh and works to dilute pollutants like odors and VOCs (volatile organic compounds) from offgass from household products.  


Bonus Room Buildout


  • Add living and recreation space

Probably the most fun aspect of the project was the attic build-out. The space above the garage had been an unfinished space since the home was constructed. The homeowners were eager to finish the area, which was at the time being used for storage. 

E3 managed all the finishing elements, from the insulation to the installation of the new solar-powered operable skylights, to the hardwood floor. Now the homeowners and their college-bound daughter have a cozy area for movie nights, gatherings with friends, and a place for yoga and exercise.

Before: The area above the garage was an unfinished storage area. 

Bonus room before renovation













After: E3 transformed the space into a functional, welcoming rec-room.

Finished rec-room         New finished family rec-room



After the project completed, E3 came back and re-tested the home to verify performance improvements. The amount of conditioned air that the duct systems lost to the outdoors was reduced by 54% for the main-floor system and by 100% for the upstairs systems. Because the main upper attic was encapsulated with sprayfoam, the second-floor duct systems is now contained inside the insulated shell of the house and doesn't leak anything to the exterior. All that conditioned air stays inside the home home and helps increase overall efficiency. 

In addition to the huge energy saving potential from duck-leakage reduction and the implementation of more efficiency heating and cooling systems, the homeowers are also enjoying a new finished sapce, a fresher home, balanced and controllable comfort, and an overall higher-performing home. The homeowners love the new space, especially the new skylights that open and close using solar power! 

When you're ready for a home-performance upgrade, call E3 INNOVATE. From new HVAC systems to new spaces, we can take care of everthing!