It’s the norm rather than the exception for a central split-system air conditioner to have one component fail before the other. Most often, the outside unit, exposed to the elements, quits before the inside unit. When this happens, you’ll have to make a decision – whether to replace the component that’s failing, or replace the indoor and outdoor A/C units with a whole new system. In most cases, the second choice is the way to go. Here are some of the reasons. Matched Sets Are Designed to Work as a Team The interior and exterior units of your split-system air conditioning system were engineered to work as team. This provides the best prospect for the A/C’s advertised efficiency and performance. While you may be able to match a new outside unit with the inside component, it will never operate as well as a matched system. If you upgrade to a new, matched air conditioner, you can take full advantage of advances in technology, such as variable-speed and multi-level components in the air handler and compressor.

This may not be possible when matching a new component with an old one. Take Advantage of Improved Energy Efficiency If you purchase a new split-system A/C featuring a high seasonal energy efficiency ratio (SEER), you’ll benefit long-term from lower energy bills. However, if you match a new outside unit with the old inside component, your system will not achieve the rated cooling efficiency. Age Difference Can Be a Problem If you’re not replacing the indoor and outdoor A/C units at the same time, you probably will continue mismatching the air conditioner components in the future. On the other hand, if your outside unit fails tomorrow, the inside unit probably doesn’t have that long before it goes, too. Upgrade to a whole new system. Replacing the indoor and outdoor A/C units at the same time is the wise decision. For help finding a new split-system A/C for your Northern Virginia or Maryland home, please contact us at Modern Mechanical. Our goal is to help educate our customers in Northern Virginia and Maryland about energy and home comfort issues (specific to HVAC systems).  

For more information about indoor and outdoor A/C units and other HVAC topics, download our free Home Comfort Resource guide.Unless you have a zoned system, a single AC unit can have you changing the thermostat constantly. It can be challenging to maintain a comfortable temperature in an older two-story home with only one central air-conditioning unit. Using two systems has many advantages over a single unit, but it is not always the best choice. The age and design of your house may affect your decision, along with the costs of purchasing and running a second central air-conditioning unit. Cost Considerations Purchasing two central air-conditioning units can be more expensive initially than purchasing a single unit, but the cost difference may not be as much as you think. You need either two smaller units or one larger unit to run the entire house. The added cost of the second unit may be offset by the energy savings. Much depends on your house and how you use the air conditioner. Temperature Balance In many older homes, it is difficult to keep the entire house at the same temperature.

The second floor is often much warmer than the first, so one area of the house often seems too hot or two cold. water from window ac unitUsing separate central air-conditioning units for each floor allows you to maintain a comfortable temperature throughout the entire house. ac unit b and qEnergy Savings A single non-zoned central air-conditioning unit requires you to keep all areas cool, even when some are not in use. how to remove an old ac unitIn many homes, the first floor can be cooled during the daytime and turned off at night, while the upstairs bedrooms may only need to be cooled at night. In this situation, separate central air-conditioning units can result in significant energy savings. This situation can also be solved with a zoned air-conditioning unit.

System Failure If one of the central air-conditioning units goes out, you may be able to keep the house cool enough with the other unit until repairs are made, though this is only important in areas where summer temperatures are extreme. Having two units also doubles the chance of system failure and increases the cost of repairs overall. Advantages of a Zoned System It is possible to install a single central air-conditioning unit, with two or more thermostats, that can cool the house evenly. A zoned system includes dampers within the ductwork that open and close to regulate the flow of air and temperature in each zone. A regular central air-conditioning system, by contrast, pushes cool air to all parts of the house. A single zoned system has many of the advantages of a two-unit system: The house is divided into two or more zones -- in this case, upstairs and downstairs. Each zone of the house can be turned down or closed off to save energy. The thermostat in each zone controls the temperature in the zone.

A zoned system costs more to install than a regular single air-conditioning unit, but the energy savings may make up the difference over time. References Green Building Advisor: Keeping Cool in a Two-Story HousePurchase HVAC: What if I Have a Two-Story Home?Austin Air Companie: What Is a Zoned Air Conditioning and Heating System? Photo Credits Image Source/Photodisc/Getty Images Suggest a CorrectionThis section will help answer some of the questions we are asked most often. Q. How big is the new M-Series indoor A. Mr. Slim's indoor unit is compact and mounts discreetly high on wall where it is mostly out of view. Q. How big is the new M-series outdoor A. Mr. Slim's outdoor unit is not bulky like the conventional style units you are used to seeing. The unit's very thin profile allows it to be mounted discreetly along the back or side of theBecause the height is minimal, a small planting of shrubbery will also keep it from plain view for a more pleasing appeal.

Please refer to table below for actual dimensions. Q. How quiet is Mr. Slim? A. Mr. Slim is designed to be quieter and more efficient than old window units, so you'll sleep easier with less worry aboutThe unit's fan is designed to deliver air quietly with only a gentle whoosh.  (That's why Mr. Slim is the first choice for thousands of churches, schools, and libraries.) Q. How does Mr. Slim work? A. Mr. Slim employs the same mechanical components as any basic air-conditioning system whose interactions cause the process ofMr. Slim is a split-ductless design, which simply means the indoor unit is separated from the outdoor unit and is connected by a gas and a liquid refrigerant line. unit is considered the hot-side during the air-conditioningThe cold-side unit is located indoors. process the compressor reverses this operation, and the heat energy is evaporated in the outdoor unit.  Then the indoor unit collects this heat energy while a fan blows air over the indoor

coil and distributes the warm air into the room. Q. What are the installation considerations for mounting the Mr. Slim M-Series indoor and outdoor units? A. The indoor unit is typically installed high on an exteriorAn exterior wall allows for easy connections between the indoor and outdoor units. The indoor unit is suspended on a wall bracket that is first mounted and secured to the wall. indoor unit is so light, there is not significant pressure placedThe indoor unit is mounted horizontally and must beFor the best circulation and air distribution the unit should be at least seven feet high or six inches below an The outdoor unit should be mounted in a convenient location to allow for easy connection to the indoor unit. place the outdoor unit up to 49 feet away from the indoor unit ifThe outdoor unit can be placed close to the wall but must have at least a foot away. The outdoor unit should be mounted on a concrete pad to assure level footing.

The fan outlet should be facing away from the home or the unit can be mounted perpendicular Q. What color is the M-Series indoor unit? A. The units are white with varying degrees of brightness across Q. Why do you need a three-inch opening in the wall to A. Unlike window units or hotel style units, which require a large wall or window opening to be cut, Mr. Slim only requires aThis opening in the wall is necessary to allow the refrigerant lines and the wiring to connect the indoor unit to the outdoor unit. This opening is sealed and insulated by your installing contractor so no drafty air leaks or water from Q. What is the I FEEL mode on the M-Series remote A. This answer applies to all newer M-Series equipment. function samples the indoor temperature for 2 minutes and then based on that temperature chooses the mode the unit will operateIf the temperature in the room is more than 79 degrees it will be set in the Cool mode at 75 degrees.

If the room temperature is 77 to 79 it will be set to the Cool mode minus 4 degrees of theIf the temperature sensed is 73 to 77 degrees then the unit will be set in the Dry mode minus 4 degrees of the current room temperature. If the room temperature is less than 73 degrees then the unit will be set in the Heat mode. "I Feel" mode the temperature display disappears and pressing the "Too Warm" or "Too Cool" button will change the set point by 2-4 Q. Why should I consider buying Mr. Slim? Mitsubishi Electric is the industry leader in ductless airOur innovations have defined cutting edgeCompare and you'll see no one surpasses Mr. Slim's performance for quiet, easy-to-use energy efficientAnd since our ductless technology carries the Mitsubishi Electric name, you know every unit is built to last. line is that Mr. Slim delivers the ultimate control of comfort for your home or office. It's true today and will be comfortably self-evident for years to come.

Mr. Slim provides all of these important Quiet and efficient operation: Mr. Slim runs at as little as 26This means that you can hold a quiet conversation or sleep without having to worry about the air conditioner interrupting No ductwork is required: You will not have to tear up walls or add expensive ductwork to basement remodels Will not take up a window:  If you take as much pride in your landscape as you do your home, you will appreciate that you can enjoy your handy work from the inside now that you have gotten your window view back. If you own a window unit then you are also concerned with the security issue of someone taking it out and coming inside your home. Mr. Slim eliminates this concern. Effective zone cooling and heating: True zoning means that you can tailor individual rooms to your personal comfort tastes. Perhaps you prefer it cooler in the bedroom or kitchen. not use your guestrooms, dining room, or bonus room regularly, why

cool them day-in, day-out? Versatility: You can air condition spaces you at first thought impossible because there is no space for ductwork and you don't want a window unit. Both at the home or office, Mr. Slim is flexible enough to work in almost any room environment. Remote controlled operation and timer functions: With Mr. Slim, you can control your comfort from across the room. comes with a wireless remote controller that gives you control of temperature, fan speed, vane operation and more. function means that you can set Mr. Slim to operate when you needFor example, if you know you arrive home from the office around 6:00 PM, you can set Mr. Slim to turn on at 5:00PM to begin cooling before you get there. This means that you are not cooling or heating your home while you're not there, which saves you Q. PURY-100/80TMU related: What type of communications is used with the City Multi systems? A. City Multi uses a 24 to 30 volts D.C. digital communication

called Mitsubishi Network (M-net). This network voltage is generated from the outdoor unit to the B.C. controller and all theThis allows for constant communication between all components in the system that operate via the M-net. Q. PURY-100/80TMU related: Do you require a special control wiring type for the M-Net?It must be a #16 or #18 gauge, two conductor, stranded and Q. PURY-100/80TMU related: Do you need to ground the shielded cable?However it will only go to earth ground at the outdoor unit, no where else. Q. PURY-100/80TMU related: What is the best way to wire in a safety circuit for a condensate pump? For the PLFY, (ceiling mount), series there is a condensate pump already installed and the safety is factory wired. (ducted model), and PKFY, (wall mount), *(with the exception of the PKFY-08NAMU-A)*, series there is a red jumper located on the circuit board at CN31. You simply cut the red jumper wire and