Huge HVAC Energy Savings

Putting the ducts in conditioned space has been the Holy Grail of ducted heating and cooling systems for some time. The CVRH project has proven that the ducts do not have to be in conditioned space to achieve high efficiencies.

Three of these homes had the duct systems shortened, sealed, and super-insulated. By reducing the duct rest-rictions and reducing the size of the units, the cooling coil airflow was increased from an average of 297 CFM per ton to an average 534 CFM per ton. The existing systems then performed much better as shown in the figure to the right.

Reference HVAC Systems – the Yardsticks

Each of the houses has reference heating and cooling systems fully contained within the conditioned space (except the condensing units for the air conditioners). to operate on alternating time periods with the existing HVAC system.

Huge Energy Savings

Myth: "You have to rebuild the house to save 50% or more of the cooling energy". NOT SO

The three oldest homes saved an average of 77.7% of the cooling energy through simple, common retrofits (ducts, HVAC, insulation, air sealing, etc.). Only the newest home fell short with a 45% cooling energy savings. That home was already well insulated, with good windows.

Prioritize by Check List

The results of this research suggests that simple checklists could be used to determine the first few things than need to be done to a house to save a significant amount of energy. It also suggests that some of these things could be done as direct install programs so that they could reach the largest number of homes.

Early Work on Houses as Interactive Systems.

In 1972, The Center for Environmental Studies at Princeton University began a study of townhomes in Twin Rivers, N.J. This was seminal work on “the house as a system”and started to reveal how houses work.