What Is Rheia?

Product Vision

The Rheia air distribution system snaps together to form a near airtight delivery system without tape or mastic. Our compact uninsulated duct and engineered thermoplastic components are UL certified to the highest standards in the industry, designed to be installed in the conditioned space of the home. Each engineered component works as part of a system, fine-tuned for quick, easy, and error-free installation.

What is Rheia?

The Rheia air distribution system uses many 3” or 4” ‘home runs’ from a central manifold to deliver air throughout the home. Each home run comprises flexible ducts with plastic connector components, all certified to standard UL181. Compared to a conventional duct system, a Rheia system will deliver the same air to each room at the same static pressure. Rheia uses multiple smaller ducts in each room rather than one or two larger ducts. For example, three 3” ducts can deliver the same air as one 6” or 7” duct. Home runs also have the advantage of not using wye branches. Wye branches and tee fittings add significant static pressure to the duct system.

Rheia Fundamentals

Ducts and equipment are located in the conditioned space of the home.

The HVAC system accounts for around 50% of the energy consumed by a home annually, and up to 30% of the energy traveling through an air handler and ductwork in an unconditioned attic is lost. For those reasons, the energy codes are driving the industry to get ducts and equipment out of unconditioned spaces. Doing so reduces cooling loads, which means smaller tonnage equipment can be specified, lowering costs and speeding up installation. The key challenge for the builder is to find room in the home to create a mechanical closet and to accommodate the ductwork. This is easier with Rheia since our ducts are smaller.

Small diameter duct supply system.

Rheia system is very compact, making it easy to route through walls without the need for large bulkheads and chases. Where they are needed, they are smaller, less obtrusive architecturally, and less costly to install.

NOT a high velocity system with quiet air delivery.

Despite being considered a ‘small diameter’ system (with 3″ and 4″ ducts), Rheia operates at the total static pressures commonly set using ‘conventional systems’. Because the fitting and diffuser components are thermoplastic and engineered to be aerodynamically efficient, and because the airflow per duct is low (typically maximum of 40 cfm), the noise levels are very low.

Works with ANY conventional air handler.

Rheia does not require special air handlers that operate at higher static pressures. Any ‘conventional’ equipment that is typically specified by builders and contractors will work. This includes the most basic single-speed air handlers. Any heat pump or gas furnaces are acceptable, making it easy for the builder or contractor to rely on their current suppliers to source equipment.

Home run layout supplied via a central manifold just like PEX.

Rheia has adopted a homerun duct design using a central manifold installed above or below the air handler. This approach makes each duct run’s airflow predictable, and when combined with adjustable dampers in each duct, makes the system very easy to balance with the original duct design predictions. A homerun layout is easy for installers to understand. This simplifies and speeds up installation only requiring each duct to be run from the diffuser back to the manifold. Trunk and branch designs are much harder to follow, with many duct sizes and reducers to install in the correct order and sequence.

Snap-fit connections air seal the system.

Sealing conventional ductwork is time-consuming, imperfect, and messy, often requiring rework to rectify leaks. Rheia uses precision-manufactured thermoplastic fittings that are engineered to fit together to form near airtight connections. The duct connects to the fittings via threaded fitting (the Ferrule) which stretches the duct slightly to create a seal. All of Rheia’s homes have passed the Energy Star leakage test requirement of 4.0cfm per 100 sq. ft. of home.

Adjustable dampers in EVERY duct run.

Current systems have limited adjustment capabilities built into the installations. To balance a home, the technician must measure the airflow at each diffuser, make an adjustment, remeasure each diffuser again and repeat the process until system balance (all airflows meet the design intent) is achieved. In reality, it is rarely done because it is time-consuming and imprecise. Rheia has adopted a different, more precise approach. Because each duct run has an adjustable damper near the Diffusers, and because Rheia provides an easy-to-use Balancing app, airflows can be accurately adjusted to meet the design airflow.

More diffusers per room improves air mixing.

It is not uncommon to see only one or two diffusers per room in a conventional HVAC system. This creates an air mixing issue. With only one or two points of delivery in a room, conditioned air is not able to fully circulate in the room, creating ‘dead spots’ where the room will feel colder or warmer. This is exacerbated by the location of the supply to the return in a room. The return can also prevent the conditioned air from adequately circulating before exiting through the return. Rheia’s approach is different. Using smaller ducts requires more ducts per room, which can deliver air from several points in the room promoting better air mixing; improving comfort by reducing the potential for hot and cold spots.

Only 16 SKUs (3” and 4” system)

A typical ‘conventional’ HVAC design uses about 75 Stock Keeping Units (SKUs) per home, and a contractor will have several thousand SKUs in their inventory stock. This is time-consuming to track and uses valuable space in a facility. Ensuring the right parts make it to the right job is also a challenge, often resulting in multiple deliveries to the job site to deliver the right bill of materials). Rheia’s low SKU count (16 components) greatly simplifies the contractor’s ordering, inventory, handling, and delivery activities.