ductless minisplit

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Choosing a New HVAC System

A homeowner looks for suggestions in updating old heating and cooling equipment

Posted on Feb 5 2018 by Scott Gibson

Jill D has done her homework, and now it's time to choose a new heating and cooling system for her Climate Zone 5B home.

There are three distinct zones to consider: the main house, a sunroom addition, and an office addition. Neither the office nor the sunroom is ducted, although heating and cooling loads there are relatively low. In the main house, the heating loadRate at which heat must be added to a space to maintain a desired temperature. See cooling load. has been calculated at between 28,000 and 36,000 BtuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. per hour, and the cooling load at between 24,000 and 36,000 Btu per hour.


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Image Credits:

  1. Green Mountain Power

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Keeping Cool in Detroit

Will a single minisplit head be enough to cool the entire second floor of a 1962 colonial?

Posted on Jun 26 2017 by Scott Gibson

Like many houses built in the 1960s, Nathan Efrusy's 2,000-square-foot colonial in Detroit has baseboard heat but no central air. A single wall-mounted air conditioner keeps the first floor of the house comfortable, but Efrusy would like to extend AC to the second floor — the question is now to do that effectively.

In a Q&A post, Efrusy says he's been given several options for cooling on the second floor, but he's leaning towards a ductless minisplit.


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Image Credits:

  1. Images #1 and #2: Nathan Efrusy
  2. Image #3: Hampton Bay
  3. Images #4 and #5: Peter Yost

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Vermont Utility Expands Heat Pump Program

Consumers get a ductless minisplit heat pump with no down payment

Posted on Apr 26 2017 by Scott Gibson

Vermont's largest electric utility is beefing up its campaign to get ductless minisplit heat pumps into the homes of more people as it expands its no-money-down pitch to consumers in its entire service area.

Homeowners who sign up get a heat pump from one of three manufacturers and finance the cost of the installation over 15 years, making loan payments from $49 to $81 per month for a single-head heat pump. There is no down payment, and Green Mountain Power says that heating bills in this Climate Zone 6 state can be reduced by between 25% and 50%. Maintenance is included.


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Image Credits:

  1. Green Mountain Power

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Are Ductless Minisplits Overpriced?

An installer’s estimate has one homeowner wondering whether he should install the unit himself

Posted on Apr 3 2017 by Scott Gibson

Ductless minisplit heat pumps have received a tremendous amount of attention in the last several years, and Peter L. would like to include one in his own house. There's only one problem: an estimate that seems far higher than it should.

"I was quoted $4,800 to purchase and install a Mitsubishi Mr. Slim 1-ton unit (MSZFE12NA)," Peter writes at GBA's Q&A forum. "That seems very high. Especially since it's a new build and the 3-inch hole is already in the wall."


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Image Credits:

  1. Scott Gibson

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Three Superinsulated Houses in Vermont

These three homes designed by Jean Terwilliger are all heated and cooled by ductless minisplits

Posted on Mar 3 2017 by Martin Holladay
prime

Efficiency Vermont, a nonprofit agency that provides financial incentives for energy-efficiency improvements by homeowners, builders, and businesses in Vermont, has developed a certification program for new homes called the High Performance Certification.


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Image Credits:

  1. All images (except Image #10 and #19) courtesy of Jean Terwilliger
  2. Image #10: Martin Holladay
  3. Image #19: 475 High Performance Building Supply

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Tweaking Plans for a Minisplit System

With heating and cooling load calculations in hand, a homeowner tries to fine-tune specs for a minisplit system

Posted on Aug 15 2016 by Scott Gibson

A GBAGreenBuildingAdvisor.com reader by the name of Green Heron has recommendations in hand from an HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. contractor for heating and cooling a Climate Zone 2 house currently undergoing renovations. But he's not sure whether the recommendations make sense.

The contractor has proposed a four-zone system using a mix of ductless and ducted minisplits, Green Heron explains in a post in GBA's Q&A Forum. A single 3-ton compressor would run the four indoor heads — two ducted units installed in the attic, and ductless units in both the kitchen and the living room.


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Image Credits:

  1. Brian Post

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Should We Promote Heat Pumps to Save Energy?

Replacing electric resistance heat with heat pumps could trim the nation's consumption of electricity by 2% — but in very cold states, gas furnaces still use less energy

Posted on Jun 2 2016 by Steven Nadel

Heat pumps are going through a period of innovation. Ductless heat pumps are more available; cold climate heat pumps have been developed; higher minimum efficiency standards for heat pumps have been established by the U.S. government; and gas-fired heat pumps have been developed.


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Image Credits:

  1. BlueberarsLair / CC BY-ND 2.0 / Flickr

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The Carbon Footprint of Minisplits

Is heating with a minisplit heat pump really ‘greener’ than heating with fossil fuels?

Posted on Mar 29 2016 by Dana Dorsett

It’s often presumed that heating with high-efficiency heat pumps has a lower carbon footprintAmount of carbon dioxide and other greenhouse gases that a person, community, industry, or other entity contributes to the atmosphere through energy use, transportation, and other means. than heating with other equipment (and often it is). But how do you really know?

Do the math!


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Ductless Minisplits May Not Be As Efficient As We Thought

New England researchers find that minisplits have lower air flow rates and lower COPs than expected

Posted on Oct 16 2015 by Martin Holladay
prime

A recent monitoring study of ductless minisplits installed in seven New England homes found that these heating appliances had lower airflow rates and lower coefficients of performance (COPs) than expected. The average COP of these air-source heat pumps ranged from 1.1 at the house with the least-efficient minisplit to 2.3 at the house with the most-efficient minisplit.

The results of the study raise at least as many questions as they answer. Perhaps the most useful outcome of the study is that it sets up a framework for recommendations that could enhance minisplit efficiency.


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Image Credits:

  1. Photo of dog on floor: Peter Talmage; all other images: Consortium of Advanced Residential Buildings

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How To Buy a Ductless Minisplit

This cheat sheet is intended for designers and builders who are confused by available equipment options

Posted on Jun 19 2015 by Martin Holladay
prime

Green builders usually specify high-performance windows and above-code levels of insulation, while striving to reduce air leaks in their homes. As a result of these efforts, most green homes have relatively low heating and cooling loads.


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Image Credits:

  1. Alex Wilson

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