Today’s high-performance homes are becoming super air-tight thanks to air sealing – one of the most cost effective energy saving measures available. Effective air-sealing, however, creates challenges for the health of occupants due to lack of fresh air, as well as possible challenges to building durability resulting from moisture build up. Highly efficient homes and their occupants need fresh air from the outside, but the energy required to condition this air reduces the energy efficiency of the home. For that reason, Energy Recovery Ventilators (ERVs) and Heat Recovery Ventilators (HRV’s) have become standard for most high-performance homes and buildings.
Unfortunately, energy or heat recovery ventilators are often an afterthought – devices added after the initial design has been completed in an effort to meet minimum ventilation standards for tightly built homes. A prevalent thought is that current ventilation standards are adequate, when in fact ASHRAE 62.2 is just a minimum ventilation standard and not based on true occupant health. While using a ventilation system that reduces energy waste is important, focusing solely on this attribute of ERVs ignores an ERV’s more important responsibility: keeping the house and occupants healthy and comfortable. The economic penalty due to home moisture problems and poor health and productivity of occupants resulting from inadequate ventilation dwarfs home energy costs. The only way to truly provide a healthier more durable home is to measure and control ventilation based on air quality data.
For these reasons, Build Equinox sought to develop a smart, high-performance ventilation system for the residential market that puts occupant health and comfort and home durability above all else. The company recently introduced its second generation ERV, called the CERV2. Designed and built in Urbana, Illinois at Build Equinox’s 100% solar power facility, this advanced ERV features Smart Ventilation with CO2 and VOC air quality sensing along with heat pump energy recovery and recirculation for superior energy efficiency and comfort. It also includes features that allow occupants to fine tune the air quality in their home.
The all-aluminum, single box design provides a simplified installation, saving time and space. Basic installation consists of connecting the four 8” ducts (return air from house, fresh air from outside, exhaust air to outside, and supply air to the house), plugging the power cord into a standard 120V, 15A outlet, and connecting the condensate outlet to a floor drain or condensate pump. Additionally, the CERV2 has two small 3” diameter utility duct ports that allow the unit to pull air from mechanical and laundry spaces that may get exceedingly cool or warm from heat pump water heater or clothes dryer operation. Distributing air from these spaces helps those rooms avoid over cooling or heating and allows those appliances to operate more efficiently.
There are two fan options for the CERV2, both are variable speed ECM fans providing up to 250 cfm at 1” external static pressure (ESP). Air filtration is done with the two standard size 10 x 20 x 1” filters, one for the fresh air and one for the return air. MERV 13 filters come with the CERV2, but owners can choose other levels if they prefer and even increase to a 2” filter. The CERV’s recirculation operating mode offers particulate filtration for interior spaces. Besides regular filter changes, the only other maintenance items are to ensure there are no blockages of the fresh air or exhaust ducts outside the home and that the condensate line remains clear.
Integrated into the front of the CERV2 is the color touchscreen user interface. A wireless remote screen is also available for homeowners who would like a dedicated controller in another location. Wifi is built in standard to the CERV2, so users also have the ability to control and monitor their system remotely using a smart phone, iPad, or computer. This service called CERV-ICE is completely free and also allows homeowners to view or download historic data for their system and receive reports of their home’s Indoor Air Quality performance over time. A live demo and product specifications can be seen at www.buildequinox.com/#takecontrol
The goal of these features is to give homeowners control over their home’s air quality and provide them both peace of mind and the information needed to make changes to ventilation settings, filter selection, or activities/products in their home that may be affecting air quality and health. Service personnel can check a unit’s operation remotely which can save any unnecessary service calls for diagnostics.
The heat pump in the CERV2 is highly efficient for energy recovery, space heating and cooling/dehumidification. It utilizes an inverter driven, variable speed compressor. The maximum capacity is up to approximately 1/3 ton with coefficient of performance (COP) over 3.5. Low outdoor temperatures don’t affect the CERV2 which has no low temperature operating limit and, unlike conventional HRVs and ERVs, the CERV2 doesn’t restrict air flow or require a preheater to prevent freezing.
The heat pump is used for energy recovery and fresh air conditioning in ventilation heating and cooling modes while in recirculation heating and cooling modes, the heat pump is used to provide some space conditioning. Dehumidification is part of the cooling function of the CERV. When it is nice outside and energy recovery is not needed the CERV2 operates in “free” heating or cooling modes.
Demand-controlled ventilation is dictated by the on-board independent CO2 (carbon dioxide) and VOC (volatile organic compound) sensors. These allow the CERV to continuously monitor a home’s air quality and automatically provide just the right amount of fresh air to maintain exceptional air quality. This level of control reduces over-ventilation during low occupancy so as to not waste energy and automatically increases ventilation to ensure healthy air during higher occupancy or polluting events. Indoor and outside temperature and humidity are also measured by the CERV2.
The CERV2 has several optional inputs and outputs making this Smart Ventilation system even more intelligent. Wireless, battery-free remote switches are available for spot ventilation, and homeowners can set unique ventilation time lengths and fan speeds for specific rooms, for example, half baths versus full baths and kitchens. Pairing ventilation switches with dampers to form zones allows further control for “precision” ventilation. There are several other wireless components that can be linked to the CERV2 for activating ventilation or controlling external devices including the Geo-Boost geothermal ground loop exchanger that further enhances the CERV’s efficiency and capacity. Input/Output channels are also available for reading signals from or controlling external wired systems.
The high-performance home market is slowly shifting, from one solely focused on energy, to one focused on building durability as well as occupant health and comfort. The CERV2 offers the high-performance ventilation system that energy efficient home owners, builders, architects, and designers have been seeking in order to match the high quality of their other energy saving/building products. Now, with the CERV2, these homes won’t just be breaking through energy code barriers, they will far exceed current ventilation standards and provide healthier more comfortable and durable homes as well.
Ben Newell is president of BuildEquinox.
