Wednesday, April 11, 2018

HVAC Design Requirements in the International Building Codes

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A look at what the codes actually require for load calculations and duct design
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Building codes, especially those related to energy efficiency, have improved a lot over the years. With building enclosures, this has made a big difference. We now have more insulation, less thermal bridgingHeat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. , and tested air barriers. On the mechanical side, the improvements are significant — reduced duct leakage and mechanical ventilation in airtight homes — but there's still a gap between some code requirements and what's being installed.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/hvac-design-requirements-international-building-codes

Wednesday, March 28, 2018

Converting Heating and Cooling Loads to Air Flow Needs

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Here’s how Manual J software takes your inputs and gives you both the BTU/hour and cfm needed for each room
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When you embark on the project of educating yourself about building science, one of the first things you encounter is the concept of heating and cooling loads. Every building has them. (Yes, even Passive House projects.) That's why we do heating and cooling load calculations. We enter all the details of the building, set the design conditions, and get the heating and cooling loads for each room in the building.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/converting-heating-and-cooling-loads-air-flow-needs

Thursday, March 22, 2018

Wingnut Real-World Testing of Basement Waterproofing

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UGL Drylok Extreme, Koster NB1 Grey, Xypex Concentrate: Do these interior waterproofing systems really work?
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Back in May 2017 I wrote a blog about negative side waterproofing (NSW). But I was still feeling troubled. The standardized test for NSW from the U.S. Army Corps of Engineers (“Standard Test Method for Water Permeability of Concrete”) is frankly really complicated; the schematic seems impossible to decipher (see the Image #1 at the right). Instead of using this test, could we do a real-world, Wingnut-style test for negative-side waterproofing?

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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/wingnut-real-world-testing-basement-waterproofing

Wednesday, March 14, 2018

Is a Ventless Fireplace More Efficient Than a Condensing Furnace?

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An energy conversion conundrum for building science geeks
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One of the primary benefits of a ventless gas fireplace is that you don't lose any heat up the flue. That's because there isn't a flue, of course. (The potential problems with indoor air quality, however, outweigh any benefits, so don't run out and buy one just yet. Or ever.) That ought to make it a winner for heating efficiency in comparison to any vented heating appliance, such as furnace or boiler. Even the highest efficiency condensing furnaces still lose some heat in the exhaust gases that go up the flue.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/ventless-fireplace-more-efficient-condensing-furnace

Wednesday, February 28, 2018

Advice for Getting the Most Out of Your Insulation Contract

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Hint: The same amount of insulation doesn’t always give you the same R-value
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I love insulation. It's a wonderful thing because it saves energy. It makes buildings more comfortable. And it's pretty inexpensive considering how long it lasts (or should last). I get asked a lot for my opinion on the best insulation to put in a building and my answer is straightforward: A well-installed insulation is the best. I like fiberglass. I like cellulose. I like spray foam. I like mineral wool. I like blown, sprayed, batt, and rigid insulation.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/advice-getting-most-out-your-insulation-contract

Thursday, February 22, 2018

Installing Insulation With the X-Floc Ventilated Dry Injection System

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A Massachusetts company claims, “We don't just do cellulose; we do it better.”
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At the end of my recent blog on Kooltherm rigid phenolic foam insulation, I mentioned that the roof and wall assemblies at an energy retrofit project in Brattleboro, Vermont, were insulated with cellulose by a company called American Installations.

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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/installing-insulation-x-floc-ventilated-dry-injection-system

Wednesday, February 14, 2018

Is R-8 Duct Insulation Enough?

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Code requirements are always a compromise between what’s best and what’s practical
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If you know a little building science, you've no doubt seen a lot of problems that occur with air distribution systems. Ducts just don't get anywhere near the attention they deserve in most homes.

I've written about ducts quite a bit here and have shown problems resulting from poor design and installation. We all know how stupid some of those problems are. So today I'm going to talk about a problem that doesn't get nearly enough attention: duct insulation — even when the design and installation are perfect.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/r-8-duct-insulation-enough