Heat Losses Are Way More than Planned

Posted on April 19,2015 by ScottG in ductless minisplit

Bob Holodinsky was hoping for a better outcome from the heat loss calculations he received for his new Peterborough, Ontario, home — calculations that appear to have upset his plans for heating with a ductless minisplit. "I thought I was on the right track," he writes in a Q&A post at GreenBuildingAdvisor, "but now I am not so sure."

Stop Using Propane and Oil and Go Electric

Posted on April 19,2015 by user-1117568 in air-source heat pump

One of the biggest mistakes many builders make is to install a heating system fueled by propane or oil heat without considering an electric heat pump. In most cases that choice is costing the owners hundreds (or even thousands) of dollars a year in higher energy bills.

New Englanders Love Heat Pumps

Posted on April 19,2015 by ab3 in air-source heat pump

Last week I went to NESEA's Building Energy conference, and I think I heard three terms more than any others: heat pump, net zero, and passive house. (The second most popular trio was beer, wine, and whisky, but that may have something to do with the folks I was hanging out with.) So let's get right to the important question here: Why do these people in the cold climate of New England love heat pumps so much?

Settling In to My Renovated Cottage

Posted on April 19,2015 by CarlSeville in green renovation

I’ve been living in my renovated house for about two months now, and, with the exception of my hot water issue and ice on my windows, everything is working pretty well.

HVAC for a ‘Pretty Good House’

Posted on April 19,2015 by ScottG in ductless minisplit

Matt Mesa is looking ahead to retirement in a new, one-level house in Hood River, Oregon. It's going to be a Pretty Good House, a phrase coined to describe a well-insulated house of an appropriate size.

Report on Our Ductless Minisplit Heat Pump

Posted on April 19,2015 by AlexWilson in air-source heat pump

It’s been pretty chilly outside, if you haven’t noticed. A number of people have asked me how our air-source heat pump is making out in the cold weather. I wrote about the system last fall, well before we had moved in. Is it keeping us warm? We’ve only been living in the house for a few weeks, but here’s a quick report.

Practical Design Advice for Zero-Net-Energy Homes

Posted on April 19,2015 by user-1095434 in Daikin Altherma

First of all, thank you very much to all of you who contributed to this thread. I agree with all of you completely.☺ Remember, the reason Internet discussions are so acrimonious is because the stakes are so low…

One Minisplit or Two?

Posted on April 19,2015 by ScottG in air-source heat pump

Christopher Vernott is an architect at work on his own home — a tight, well-insulated house in southeastern Connecticut — and the time has come to rough-in the heating and cooling system. Because of the double-stud wall construction, triple-glazed windows, and careful air-sealing, his heating and cooling loads are low, he writes in a Q&A post at Green Building Advisor.

Heating with a Minisplit Heat Pump

Posted on April 19,2015 by AlexWilson in air-source heat pump

Thirty-five years ago, when I first got involved with energy efficiency and renewable energy, the mere suggestion that one might heat with electricity would be scoffed at by those of us seeking alternatives to fossil fuels. Amory Lovins, founder of the Rocky Mountain Institute, likened using electricity for heating to “cutting butter with a chainsaw.” Electricity is a high-grade form of energy; it doesn’t make sense to use it for a low-grade need like heating, he argued.

A Stupid — and Illegal — Way to Air Condition Your Garage

Posted on April 19,2015 by ab3 in air conditioning

Sometimes people do the craziest things. Take that photo at right, for example. That's a new home being built in Austin, Texas. The arrows point to three air conditioning ducts. In the garage. Yes, they're air conditioning the garage.

Putting the Duct Back in Ductless

Posted on April 19,2015 by ScottG in ductless

Ductless minisplits have a lot going for them. These high-performance air-source heat pumps operate efficiently at much lower outdoor temperatures than standard heat pumps, and they don't suffer the same energy losses due to leaky ducts. A tight, well-insulated house may need only one or two wall-mounted heads to maintain comfort indoor conditions, in summer and winter. It's the "wall-mounted" part, however, that not everyone warms up to.

Loving My Minisplits

Posted on April 19,2015 by CarlSeville in air conditioner

Last year, still living in my little cottage due to delays and problems attempting to build a new house in my historic district, I finally got tired of the old gravity floor furnace and window air conditioners and decided to spring for a new HVAC system. I looked briefly at installing a central ducted system, but I realized that I had really enjoyed the zone control that the window units had afforded me.

How to Choose the Right Mechanical System

Posted on April 19,2015 by ChrisBriley in boiler

With any house, there are so many variables that influence the decision to choose one particular mechanical system over another: climate, house size, cost, local availability and cost of fuels and materials, and the lifestyle and preferences of the occupants. There is no “one-size-fits-all” system that we can reliably prescribe for all projects. Phil and I sat down over a good winter cocktail to share our views, anecdotes, battle scars, and wisdom on this important subject.

Two Years With a Minisplit Heat Pump

Posted on April 19,2015 by user-1095434 in air-source heat pump

With the exception of one week in February 2011 where I switched back to the oil boiler to take some data before it went away, the Fujitsu 12RLS has now been heating the house for two years. The dedicated meter for the heat-pump system reads 2,584 kWh. So, it cost about $250 per year to heat our house, in mostly milder-than-normal weather. This is about 1/4 the cost of operating the oil heating system.

Living With Point-Source Heat

Posted on April 19,2015 by user-1095434 in ductless minisplit

When we yanked the oil boiler, we replaced it with a wall-mounted minisplit heat pump in the main level open area that includes kitchen, dining, living and our little office area. We closed off the first-floor bedroom and bathroom so those rooms are only heated by conduction and air leakage through the walls, and so they get cold — in the high 40°Fs at the lowest last winter.

Installing a Ductless Minisplit System

Posted on April 19,2015 by user-1095434 in ductless minisplit

The Island Cohousing houses were designed to have heat and domestic hot water (DHW) supplied by an oil-fired boiler. (Time for a pedantic distinction: a furnace heats air and blows it around a house, and a boiler heats water which is pumped around the house). They chose a pretty good boiler: a German Buderus G115. The two-bedroom houses got two heating zones' worth of fin-tube baseboard heat, one zone per floor level. The three- and four-bedroom houses have a third zone, for the first floor ell.

A New Encyclopedia Article on Ductless Minisplits

Posted on April 19,2015 by GBA Team in ductless minisplit

With each passing month, GBA's library of articles and blogs gets deeper. For example, we recently added a new article on Ductless Minisplit Heat Pumps to the GBA Encyclopedia. Ductless minisplits differ from conventional air-source heat pumps in several ways: first of all, they are extremely efficient, in part because of the use of inverter-driven compressors. Secondly, many of these units can operate efficiently at very low outdoor temperatures.

Just Two Minisplits Heat and Cool the Whole House

Posted on April 19,2015 by user-756436 in Carter Scott

Carter Scott was one of the first builders bold enough to build a cold-climate home heated by only two ductless minisplit units (one in the downstairs living room, and one in the upstairs hallway). Skeptics predicted that the unheated bedrooms would be cold and uncomfortable. Yet Scott was confident that the home’s excellent thermal envelope — with high-R walls, triple-glazed windows, and low levels of air leakage — would keep the homeowners comfortable even when the bedroom doors were closed.

Air-Source or Ground-Source Heat Pump?

Posted on April 19,2015 by ScottG in air-source heat pump

Dana is building a tight, well-insulated house in climate zone 6 and now faces a choice between a ground-source heat pump and an air-source heat pump for heating and cooling. “After the 30% tax incentive, there is not much increase in cost for the geo system,” Dana writes in a Q&A post at GreenBuildingAdvisor. “I am being told different stories in regard to system performance and longevity of equipment (depending on what side of the fence you’re on).”

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