Putting the Duct Back in Ductless Mini-Splits Last week, (EVER rater and Green Curmudgeon) Carl Seville and I took a trip up to Suwannee, Georgia to visit the Mitsubishi HVAC facility and learn more about their ductless heat pumps. I've mentioned here before that when I get a chance to build a house for myself again, I'd like to eliminate the ducts by using ductless mini-split heat pumps, and Mitsubishi is one of the top brands. Here's why I want to go ductless: Duct systems can be done right but almost never are, thus robbing the heating and cooling system of its effectiveness and efficiency. Duct systems take up a lot of space in attics, basements, and other parts of the house. HVAC technicians don't understand - and often don't care about - ducts. Mini-splits are some of the most efficient systems (up to 26 SEER). Mini-splits come in smaller sizes and can better match the heating and cooling loads in the house. Mitsubishi's line of residential ductless heat pumps is called the Mr. Slim.

It's a split system heat pump, which means that the compressor and condensing coil are outdoors, and the evaporator coil and blower are indoors. In that regard, it's like your typical 'central' air conditioner or heat pump. You can tell if a house has a mini-split by looking at the outdoor condensing unit (photo right). They're thinner and smaller than the typical ducted system condensing unit. The indoor unit can be mounted on a wall, set into the ceiling, or sit on the floor. At the Mitsubishi facility, we saw all three styles, and you can see photos of them below. Wall mount (set off from the wall here but mounted flush in a home) Floor mount (can be recessed into the wall) In addition to coming in smaller sizes (down to 6000 Btu/hour, half the minimum size of regular system), mini-split heat pumps can modulate the amount of heating or cooling through variable refrigerant flow (VRF) to match the actual loads in the house, not just the design loads. They're also ideal for zoning a house and limiting the amount of energy you use for heating and cooling.

The knock against mini-splits is that some people find them unattractive. They don't want to have that piece of equipment on their wall, even if it is quiet. Ceiling cassettes are a good alternative. new ac unit dallasDucted mini-splits are another, and they allow you to hide the head above a dropped ceiling, for example, and run short ducts for the return and supply air.wholesale ac units prices Another drawback is that even 6000 Btu/hour is too large for a high performance home that's going to have several heads (the indoor unit). 10 ton air conditioner costThe reason that Mitsubishi does this seems to be for ease of manufacturing. They make as few different evaporator coil sizes as possible. Even with these weaknesses, the ductless mini-split heat pump is a great idea and, I believe, will increase in popularity because of the many advantages.

There's a ductless heat pump project in the Pacific Northwest that promotes and tracks the installation of these systems. I heard about this from Bruce Manclark at the recent ACI conference in San Francisco, and he said they've got a 98% customer satisfaction rate through about 10,000 installations. What do you think? Is a ductless mini-split heat pump in your future? Or are you gonna stick with this? heating & cooling distribution Sign up to receive new posts right from your inbox! Recent PostsInterior Design Q&A: Add Color to an Old HomeSeptember 18, 2016Interior Design Q&A: Selecting Furniture for DecorSeptember 8, 2016Interior Design Q&A: Mixing Light, Dark in KitchenAugust 21, 2016Interior Design Q&A: Colors for Open Kitchen, Dining RoomAugust 2, 2016How Geothermal HVAC Systems Work and the Benefits They ProvideJune 30, 2016Categories Corporate News and Announcements Disaster Preparedness, Response, Cleanup and Restoration Property Development and Historic Preservation

Remodeling and Interior Design Residential HVAC, Plumbing, and Electrical Tuckey in the CommunityHVAC concerns are critical for those who want to live comfortably, whether they live in a cold climate or a place that tends to be warm. For many people, the type of heating and cooling system that they use has the biggest impact on how comfortable they are when the weather is extreme. Because of this, it's important that consumers understand the benefits of choosing a high velocity heating and cooling system Less leakage means more delivered efficiency While air conditioning systems are traditionally measured by ratings like the Seasonal Energy Efficiency Rating (S.E.E.R.), the problem with this approach is that it does not take into account the actual output of cold and warm air. Since high velocity heating and cooling systems use just a third of the space required in a conventional system, they have less surface area, meaning there is less leakage. No need for significant home altering

Many people who live or work in older buildings know that these structures often don't have a centralized heating or cooling system. Since these buildings are too old for significant renovations that would allow them to support centralized HVAC systems, tenants are forced to rely on baseboard radiators and in-window air conditioning units. These solutions are often loud and difficult to manage. On the other hand, the flexible ducts that are used with a high velocity heating and cooling system can be installed almost anywhere. These ducts can be snaked through existing holes in the walls and floors; no need to worry about noisy, disruptive metal ductwork that leaves a mess everywhere. High velocity heating and cooling systems are less drafty Drafts are a common problem with traditional air conditioning units, since they have a tendency to push huge amounts of air into a room at once. This leads to uneven temperatures, especially in large areas like living rooms or open offices.

With high velocity heating and cooling systems, this problem is avoided. These kinds of systems cool a room by using suction to create a gentle stream of air that circulates through the space, causing it to be heated or cooled evenly. High velocity heating and cooling systems save electricity With a conventional HVAC system, ratings are determined using the S.E.E.R. formula, BTU divided by Watts. The problem with this rating is that it is only based on the equipment used for heating and cooling; it doesn't take into account the distribution system that it is connected to. Because conventional systems have more leakage from hot attics and larger ducts that are more susceptible to developing cracks and slits, high velocity heating and cooling systems use much less electricity to cool the same amount of space. This is especially true when ducts are inside the space that is being heated or cooled, because it means you can downsize the condenser. With a high velocity heating and cooling system, you don't need to worry about fitting a huge metal unit or large, bulky ducts in your home or commercial building.