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Mini- and Multi-Split-System Air-Conditioners
Mini-splits and variable refrigerant flow (VRF) multi-splits are decentralized split systems that hold a variety of advantages over conventional central air-conditioning systems—particularly where zone control and flexibility is key, and where cooling, dehumidification, and ventilation will be treated separately. For cold climates, mini- and multi-splits offer a mainstream choice for projects considering low-temperature air-source heat pumps. Some multi-split systems are capable of cooling and heating simultaneously through different indoor units, allowing transfer of heat within a building. For large commercial systems, VRF multi-split systems provide up to 20 tons (240,000 Btu/hour or 70 kW) of cooling each; multiple systems can be combined for more cooling. Simpler mini-split systems have two tons (24,000 Btu/hour or 7.0 kW) or less of cooling capacity for homes or light-commercial buildings. Products listed here are not based on a specific efficiency cut-off because of the wide range of options and system-specific advantages. Also, there is a lack of widespread published efficiency numbers, and the Department of Energy recognizes in some cases that testing procedures are inadequate. However, some mini-split models have published efficiency numbers based on ARI testing and may be Energy Star listed. GreenSpec recommends choosing mini-splits that have an inverter-based variable-speed compressor (to take advantage of partial-load efficiencies) and must provide at least 50% of rated capacity when the outside air temperature is 17°F.
Daikin Single-Split and VRV-S Daikin AC (Americas), Inc.
Daikin’s single- and multi-split air-conditioning units and VRV-S heat pump supply cooling and heating for residential and light commercial applications. The RXS and RX systems use non-ozone-depleting R-410a refrigerant to supply between 0.75 and 2 tons of cooling, connecting one outdoor compressor to one indoor air handler. Daikin’s multi-split systems connect two to four zones and are available with ductless or ducted fan coils and a seasonal energy efficiency ratio (SEER) of up to 19.5. The RXYMQ system comes with the VRV-S heat pump and an inverter-controlled, variable-speed condenser capable of running up to eight air handlers. These three- and four-ton models are available in wall, floor, and ceiling units. The VRV-S controllers come with “home leave” and “night set” modes and an infrared motion sensor that adjusts the temperature after 20 minutes to reduce energy consumption by 20% (cooling) to 30% (heating).
City Multi Mitsubishi Electric Sales Canada Inc.
The City Multi VRFZ (variable refrigerant flow zoning) systems provide controllable zone heating and cooling for large residential and commercial applications, making it possible to simultaneously heat some rooms while cooling others. The smallest VRFZ, the S-series, provides up to 3 tons of cooling capacity, but with minimal zone control, while the modular Y-series can provide up to 20 tons of cooling capacity and maximum zone control. The R- and Y-series use an inverter-controlled compressor that improves efficiency by adjusting to indoor and outdoor temperatures. The Y-series is available with the company’s H2i inverter, which can provide more than four hours of heating in one continuous cycle, according to Mitsubishi. The W-series, for large commercial applications, is installed indoors and uses water as a heat-exchange medium. Mitsubishi’s City Multi Controls Network make it possible to monitor, schedule, and adjust the temperature of as many as 2000 indoor units.
Friedrich Air Conditioning
Friedrich’s mini- and multi-split air-conditioning units and heat pumps for residential and light commercial applications are available in wall-mount (one to four zones), floor/ceiling universal mount, ceiling-suspended, and ceiling cassette models. The single-zone M18YF has a seasonal energy efficiency ratio (SEER) of 19 while providing 1.5 tons of cooling and 1.8 tons heating. The four-zone M36QYF provides 2.9 tons cooling and 3.0 tons heating, with a SEER ratio of 15. The multi-zone and universal models come with wireless remote controls coded for each zone and include 24-hour timers. The suspended and cassette models come with wired controls. All ceiling units come with self-diagnostic programs and can be configured to bring in ducted fresh air. Friedrich’s inverter technology and non-ozone-depleting R401a refrigerant are standard on all units.
Sanyo ECO-i SANYO HVAC
Sanyo's ECO-i VRF (variable refrigerant flow) provides ductless heating and cooling for small residential, commercial, and industrial applications. The ECO-i units use non-ozone-depleting R410a refrigerant and can provide between 3.2 and 20.7 tons cooling and 3.6 and 23.2 tons heating, depending on model and configuration. Larger units can be connected to as many as 40 indoor units. Some of these VRF units have a coefficient of performance over 4.0 at full load, according to the company (most heat pumps are between 2.0 and 3.0). These systems require a single refrigerant pipe network and only one building penetration. Redundancy is built into large, multiple-compressor configurations, so if one compressor fails the other will take over. Wireless and wired controllers are available to manage temperature, airflow, and systems diagnostics.
Mr. Slim Mitsubishi Electric Sales Canada Inc.
The Mr. Slim ductless mini-split systems supply air conditioning and heating for residential and small commercial applications. These systems are comprised of outdoor condensers and small interior units connected by lines carrying ozone-safe R410a refrigerant. The interior units contain coils and a fan that cool or heat a room’s air depending on need. The Mr. Slim M and P series are available in air-conditioner-only configurations or with heat pumps, and are capable of delivering between 9,000 and 42,000 Btu/h (cooling) and 9,000 and 45,000 Btu/h heating, depending on model. The M-series are wall-mounted and are available in single-zone and multi-zone models. The P-series are wall- or ceiling-mounted, multi-zone units made for larger homes and commercial applications and are available with Mitsubishi’s “Hyper-heating inverter” (H2i) technology and wireless controls. H2i inverters work in temperatures as low as -13ºF (-25ºC) and maintain consistent temperatures while avoiding inefficient on-off cycling. All Mr. Slim units come with anti-allergen filters.
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Federal Tax Credit
On February 17, 2009, President Obama signed a stimulus bill (The American Recovery and Reinvestment Act of 2009) that made some significant changes to the energy efficiency tax credits.
Improvements made in 2009 will be claimed on your 2009 taxes (filed by April 15, 2010) — use IRS Tax Form 5695 (2009 version) — it will be available late 2009 or early 2010.