Other Mechanical Systems

Whole-House Fan Air-Sealing Details

Posted on April 25,2015 by Daniel Morrison in Finished attic

Keeping Ducts Indoors

Posted on April 25,2015 by user-756436 in conditioned space

If you live in New England, you know that furnaces are installed in basements. But any New Englander who moves to Oregon soon learns that furnaces are installed in garages. And anyone who retires to Texas discovers that furnaces are installed in unconditioned attics. Of course, there are many other examples of similar regional differences in construction practices. But this is one regional difference that matters. New Englanders have it right: furnaces and ductwork belong inside a home’s conditioned space, not in the great outdoors.

What Were They Thinking?

Posted on April 25,2015 by CarlSeville in Batts

I’ve been doing HERS ratings and green building certifications for several years now, and I have run across some pretty scary things during inspections that sometimes make me wonder what everyone was thinking. Now, I was a contractor for a long time, and I understand the challenges of getting things done on time, correctly, and within the budget, and by no means am I trying to minimize those challenges. What does amaze me is how little attention some contractors and trade contractors pay to the details as their projects are underway.

An AC Sizing Benchmark for High-Performance Homes

Posted on April 25,2015 by ab3 in air conditioner sizing

One of the most frustrating parts of my job as a Home Energy Rating (HERS) provider is dealing with the size of air conditioners installed in Energy Star homes.

Direct-Gain Passive Solar Heating

Posted on April 25,2015 by AlexWilson in deep energy retrofit

Over the past two weeks I've written about two relatively obscure passive solar heating strategies: isolated gain using sunspaces; and indirect gain using a Trombe walls. This week I'll cover a far more common and cost-effective approach: direct-gain.

Ground-Source Heat Pumps, Part 3: Five Questions

Posted on April 25,2015 by ChrisBriley in deep energy retrofit

I sent an email to Jeff Gagnon and Jim Godbout, and asked them five basic questions about ground-source heat pump installations. In this part of the Green Architects' Lounge podcast, Phil and I take some time to review and compare their answers. We also take a moment to touch on the subject of ozone-depleting refrigerants.

Ground-Source Heat Pumps, Part 2: Rules of Thumb

Posted on April 25,2015 by ChrisBriley in Chris Briley

In Part One of this episode from the Green Architects' Lounge, we only scratched the surface. Now it's time to really dig in and decide if a ground-source heat pump system is right for you, and if so, to start planning for it.

In Part Two of the podcast, we discuss:

  • A tale of two houses: Chris shares a story of two houses—one a success, and one that had to abandon using a ground-source heat pump
  • Rule of thumb for flow: 3 gal. per minute per ton of heating/cooling
  • Biomass Boilers, Part 2: Taking Wood Hauling Out of the Users' Hands

    Posted on April 25,2015 by ChrisBriley in Other Mechanical Systems

    For Part Two of this Green Architects' Lounge episode, we are joined once again by our good friend Pat Coon, from Revision Heat, to discuss the topic of biomass boilers. In the second installment of this epic trilogy, Phil, Pat, and I wrap up our discussion of log gasification boilers and introduce our listeners to the concept of wood pellet boilers. If you missed Part One, you might want to give that a listen first, especially since it gives you the recipe for the perfect red Manhattan (which goes very well with this smoky topic).

    Passive Hot Air from Everyday Materials

    Posted on April 25,2015 by Mike_Maines in Heat recovery ventilators

    At the Unity, Maine, headquarters of the Maine Organic Farmers and Gardeners Association (MOFGA), engineer Jay LeGore has harnessed the power of the sun to replace about 200 gallons of propane a year.

    Ground-Source Heat Pumps Have Low Operating Costs

    Posted on April 25,2015 by jgeyer@buildinggreen.com in geothermal

    Ground source heat pump (GSHP) systems collect ambient heat from the soil within 400 feet of the ground surface. This heat is concentrated by vapor-compression refrigeration units and delivered to conditioned spaces by conventional forced-air or hydronic mechanical systems. They reverse this process when in cooling mode. The technology has been used since the 1950s, so there are few unknowns. It works in nearly any climate or soil condition, and no longer needs to be proven. GSHP efficiencies are multiples of conventional HVAC equipment conversion.

    Are Solar-Powered Attic Ventilators Green?

    Posted on April 25,2015 by Peterbilt in fans

    At face value, attic exhaust fans make a lot of sense: if your attic is too hot, you force more air through it to cool it down. To be efficient, you use a solar-powered attic exhaust fan. When the sun is shining and heating up your attic, that’s when the photovoltaic panel wired to the exhaust fan powers the fan. Pretty slick.

    Quebec Town Bans Wood Stoves

    Posted on April 25,2015 by user-756436 in Energy from Biomass

    ##Town Orders Existing Wood Stoves to Be Removed## HAMPSTEAD, QUEBEC — The town of Hampstead, Quebec, a suburb of Montreal, has banned the installation of wood stoves and ordered all existing wood stoves to be removed within the next seven years. The new bylaw covers stoves, fireplace inserts, furnaces, and boilers that burn wood or wood pellets, all of which must be removed by November 3, 2015.

    Green Basics Boilers

    Upgrade a boiler or furnace with a vent damper

    Posted on April 25,2015 by Peterbilt in deep energy retrofit

    **Reduce the amount of heat that goes up the chimney.** Adding a vent damper to a boiler or furnace is an easy way to cut energy losses. The damper prevents heated air from being pulled into the flue when the heating appliance is not running. When there's a demand for heat and the furnace or boiler starts to run, the damper opens to improve draw.

    Learn more in the Green Building Encyclopedia

    [Boilers](node/656 "A New Generation of Boilers Is Super Efficient")

    [Furnaces](node/657 "The Highest Efficiency Rating Is Found in Condensing Furnaces")

    Heat water with the sun

    Posted on April 25,2015 by Peterbilt in New construction

    **Solar hot water is cost-effective renewable energy.** Renewable energy systems can make a tremendous difference in reducing the amount of fossil fuels consumed to operate a house. Solar water heating is often the most cost-effective renewable energy system for a house. The many types of solar water heaters including flat-plate collector systems with closed-loop antifreeze collector fluid, drain-back systems, evacuated-tube systems, passive thermosiphon systems, and integral-collector-storage systems. Some active solar water heaters use integral photovoltaic (PV) panels to power the pumps.

    Select condensing boilers and furnaces

    Posted on April 25,2015 by Peterbilt in New construction

    **More heat for less fuel** About 10% of the heat from the burner in a boiler or furnace is held in the water vapor in flue gases. In a condensing unit, much of this moisture condenses in a heat exchanger, capturing the latent heat before combustion gases go out the flue. The moisture (condensate) then drains away. The full benefits of a condensing boiler are not realized unless return water temperatures are kept below approximately 120°F. Exhaust gases are cool enough to be vented in plastic pipe.

    Choose Energy Star or GreenSpec HVAC components

    Posted on April 25,2015 by Peterbilt in New construction

    **Rated equipment uses less energy.** Higher-efficiency fans, pumps, and motors meet either Energy Star or GreenSpec requirements and generally save 20% to 30% in energy costs when compared with uncertified equipment. High efficiency equipment almost always costs more but offers lower operating costs.

    Use a heat-recovery ventilation system

    Posted on April 25,2015 by Peterbilt in New construction

    **Saving energy while providing fresh air** Heat-recovery ventilation (HRV) transfers heat from exhaust air to incoming fresh air, meaning that the heating system doesn't have to work as hard to keep the house comfortable. In summer, exhaust air cools incoming air before it enters the house. Energy-recovery ventilators (also called enthalpic heat recovery ventilation or EHRV), transfer moisture as well as heat. Among the choices for ventilation, these two are the most expensive.

    Use ground-source heat pumps for heating and cooling

    Posted on April 25,2015 by Peterbilt in New construction

    **High efficiency without burning any fuel directly**

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