January 14, 2016

Affordable Net Zero Ready Housing on Cape Cod uses Lunos HRV Ventilation


Can you spot the Lunos e² units on this townhouse? Just one of many utility penetrations on these buildings.

The Residences at Melpet Farm look, at first glance, like a typical suburban development. There’s a mix of 27 one-, two-, and three-bedroom units housed in 8 farmhouse-style townhouses, clustered around a common green.

But this development in Dennis, MA is actually a $7 million project overseen by Preservation of Affordable Housing (POAH) that was designed by Brown Lindquist Fenuccio & Raber Architects, Inc. to be net zero energy ready and will utilize a photovoltaic system capable of generating 160,000 kWh annually to offset the all-electric building systems.

Take an even closer look and you’ll see some real innovation that you won’t find in average housing: Lunos e² heat recovery ventilation (HRV) systems. The Residences at Melpet Farm is now the largest multi-family project in the USA using Lunos HRVs.

Update: See results of CO2 monitoring of Melpet Farms apartment units here.

A Simple Solution: Through-Wall, Balanced Ventilation with Heat Recovery


Discreet appearance of Lunos units outside…

It’s a good thing the Lunos HRVs are there. These affordable housing units tested as low as 1.06 ACH50 (air changes per hour), so they’re super airtight. Exhaust-only ventilation isn’t a good choice for such tight spaces because the one-way exhaust stream wastes energy and doesn’t provide optimal comfort. The best strategy for indoor air quality is balanced ventilation with heat recovery.

But a lot of projects shy away from HRVs because of the high cost of installing ductwork. Add to that the congestion inside service areas of wood frame buildings, with electric, plumbing, ventilation and other building services competing for limited space. Further costs include maintenance of ducts to ensure that they don’t contribute to poor indoor air quality. For these and other reasons, non-ducted systems are more and more appealing.


…and inside

With Lunos systems there’s no compromise – you get high performance balanced ventilation with heat recovery, but the through wall units  simplify installation and maintenance while avoiding ducts.

There’s also more to this project’s story. To achieve cost and performance objectives, the designers of Melpet Farm streamlined insulation layers and air barriers by eliminating basements and attics – spaces traditionally used by the HVAC trades to run ductwork for heating, cooling and ventilation. Deprived of basements and attics, typical ducted HRV systems would have required expensive – not to mention awkward – interior soffits for all the ducts to move air between the central heat recovery units, the living spaces and the outdoors. By using the Lunos, the project saved tens of thousands of dollars in interior build-outs while making the best use of tight spaces.

In short, this project shows how through-wall, decentralized Lunos HRVs can both simplify installation and come out ahead in affordability and performance.

Flexibility of System Layout and Sizing. Ideal for Multi-Family Projects

For this multi-family project, controls were placed in mechanical rooms inaccessible to occupants.

Another requirement of any ventilation system is to provide just the right amount of air flow for a given space. The Residences at Melpet Farm consist of 27 units of all shapes and sizes – so there was no one-size-fits-all approach.

Here again the Lunos system offered a simple and flexible solution. With each Lunos e² pair providing up to 20 CFM, achieving the recommended flow rate for each unit was simply a matter of installing multiple pairs according to the square footage and number of bedrooms. With up to two Lunos e² pairs on one controller, wiring was simple as well. See our blog post Sizing Lunos e² through-wall ventilation units.

In multi-family projects, continuously run HRV systems are often best left to experienced building managers rather than the occupants. For this reason, the HRV controls were placed in mechanical rooms, and set to 10, 15 or 20 CFM to meet the specific ventilation needs of each unit and its occupants.

Lunos: Exceptional Performance. Exceptional Comfort.

Despite operating within the confines of the exterior walls, Lunos HRVs are exceptional performers. See our Lunos introduction video to understand how they work. They’re quiet – 0.12 sones at the 10 CFM setting. They’re super efficient, with up to 90.6% heat recovery. They’re simple to install, operate, and maintain. And they work.

Most importantly, Lunos HRV systems excel at exchanging stale interior air – full of CO2 and VOCs – with fresh outside air. They operate continuously at just the right air flow to create comfortable, healthy, and livable interior spaces.





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