HRV

Why Is It So Humid In Here?

Posted on March 31,2015 by ScottG in damp

From the sound of it, Andy Chappell-Dick has left no stone unturned in his quest to keep the air inside his house comfortably dry. His extremely tight new house in northern Ohio (Climate Zone 5) is built with structural insulated panels, and heated and cooled with a pair of ductless minisplit heat pumps. For ventilation, Chappell-Dick has a Venmar Kubix heat-recovery ventilator that pulls exhaust air from two small bathrooms and supplies fresh air to two upstairs bedrooms with a flow rate of between 40 and 80 cubic feet per minute (cfm).

A Heat-Recovery Ventilation System for the Potwine Passivhaus

Posted on March 31,2015 by acarango@me.com in Amherst

As they set out to build a single-family Passivhaus on Potwine Lane in Amherst, Massachusetts, Alexi Arango and LeeAnn Kim asked themselves, “Is it possible to live without burning fossil fuels?” One measure of success would be meeting their goal of net-zero energy performance. This is the ninth blog in a series.

How Balanced Ventilation Systems Become Exhaust-Only

Posted on March 31,2015 by user-756436 in air intake

Unlike the homes of our great-grandparents, the homes of most Americans are served by an array of automatic appliances and systems. When our great-grandparents returned home after a three-day absence, they would need to haul a bucket of water from the spring and light a fire in the kitchen stove before they could brew tea. Today’s homes, of course, have electricity for lighting, a furnace for warmth, an air conditioner for cooling, a water heater for showers, and internet access for Googling.

Does a Home with an HRV Also Need Bath Fans?

Posted on March 31,2015 by user-756436 in balanced ventilation

A balanced ventilation system — for example, a system with a heat-recovery ventilator (HRV) or an energy-recovery ventilator (ERV) — exhausts stale air from some rooms in a building, while simultaneously introducing fresh outdoor air to other rooms. The best balanced ventilation systems use dedicated ventilation ductwork. Usually, these systems pull exhaust air from damp, smelly rooms — bathrooms and laundry rooms — and introduce fresh air to the rooms where people spend most of their time — bedrooms and the living room.

My Earth Tube Story

Posted on March 31,2015 by MalcomIsaacs in earth tube

I saw my first “earth tube” back in 2004, on a tour of row houses in Darmstadt, Germany — a tour which had been organized by the Passivhaus Institut (PHI) to show international visitors some examples of Passivhaus construction. As a visiting Canadian engineer specializing in residential energy efficiency, this was a novel and, for me, unheard-of way to temper incoming ventilation air from extremes of heat and cold.

Commissioning Our Heat-Recovery Ventilator

Posted on March 31,2015 by AlexWilson in airflow

In last week's blog I described our state-of-the-art Zehnder heat-recovery ventilator (HRV), explaining its various features and specifications. This week I’ll review what should be a critical step in the installation of any HRV: commissioning, including the critical step of balancing the air flow. This is absolutely necessary to ensure proper operation and full satisfaction from a Zehnder HRV and most other HRVs.

Our Top-Efficiency Heat-Recovery Ventilator

Posted on March 31,2015 by AlexWilson in air-to-air heat exchanger

In last week's blog I reviewed some of the general strategies used for ventilating buildings — or not. This week, I’ll zero in on the types of balanced ventilation in which heat is recovered from the outgoing airstream to preheat the incoming fresh air.

Providing Fresh Air in Our Home

Posted on March 31,2015 by AlexWilson in ERV

One of the features in our new house that I’m most excited about barely raises an eyebrow with some of our visitors: the ventilation system. I believe we have the highest-efficiency heat-recovery ventilator (HRV) on the market — or at least it’s right up there near the top. I’ll describe this Zehnder HRV and its impressive specifications and features — but not until next week. This week I’ll provide a little background on ventilation.

The Ventilation Omission That Can Make You Sweat

Posted on March 31,2015 by ab3 in ERV

If you're designing a ventilation system, first you have to determine how much outdoor air the house needs. You can use the ASHRAE 62.2 standard or the new BSC-01 standard for that task. Then you have to decide what type of ventilation system to use: positive pressure, negative pressure, or balanced. In many green homes, the balanced system is becoming a popular choice.

Passivhaus Buildings Don’t Heat Themselves

Posted on March 31,2015 by user-756436 in ERV

For years, the English-language website of the Passivhaus Institut in Germany provided this definition: “A passive house is a building in which a comfortable interior climate can be maintained without active heating and cooling systems. The house heats and cools itself, hence ‘passive.’”

What is the Deal with Ventilation Requirements?

Posted on March 31,2015 by CarlSeville in balanced ventilation

Before I even get started, I want to point out that I am no expert on ventilation. I have learned a lot from (and rely on) many experts, including Paul Raymer, Gord Cooke, John Krigger, Joe Lstiburek, Armin Rudd, and Terry Brennan, among others. I depend on them to fuss about the details of how much ventilation a house needs.

A Chat With Henry Gifford

Posted on March 31,2015 by user-756436 in cooling

Most builders and designers involved with green building have heard of Henry Gifford. Energy efficiency experts admire his deep knowledge of heating systems and his straight talk about the unacceptably high number of HVAC problems in run-of-the-mill new buildings in the U.S. At the headquarters of the United States Green Building Council (USGBC), on the other hand, he is something of a pariah — due in part to his 2010 lawsuit that accused the USGBC of making “deceptive marketing claims.”

Is There an Alternative to a Heat-Recovery Ventilator?

Posted on March 31,2015 by ScottG in energy-recovery ventilator

The tighter the house, the more it needs mechanical ventilation. That's become a rule of thumb for energy-efficient builders, and designers often turn to heat-recovery ventilators to get the job done. These relatively simple (but not necessarily cheap) devices use the temperature of outgoing air to moderate the temperature of incoming air, thus lowering the energy penalty for providing fresh air to the whole house.

Are HRVs Cost-Effective?

Posted on March 31,2015 by user-756436 in energy-recovery ventilator

From 1977 (when the Saskatchewan Conservation house was built) until 2004 (when the first U.S. Passivhaus was built), North American builders completed hundreds of superinsulated homes. In those days, anyone interested in rating the performance of these homes was probably interested in just one metric: annual energy use.

A Few Product Highlights from GreenBuild

Posted on March 31,2015 by AlexWilson in aerogel insulation

I attended the GreenBuild Conference and related meetings in San Francisco last week. This is the largest conference and trade show in the green building field, and it is increasingly becoming the national event where large manufacturers roll out new building products. Described below are a few product highlights from the trade show that caught my eye as I wandered around. I only got through about a quarter of the trade show.

Broken Ventilation Equipment Goes Unnoticed for Years

Posted on March 31,2015 by user-756436 in energy-recovery ventilator

Years ago, when I worked as a home inspector, I was hired to perform a capital needs assessment at a Buddhist retreat center in rural Vermont. In an obscure mechanical closet I discovered a heat-recovery ventilator that the facilities manager didn’t even know existed. The HRV had been installed at least a dozen years before. The filter, which had never been changed since the day it was installed, was totally clogged. The HRV was no longer working — perhaps the motor had burned out years ago. I advised the owners to call an HVAC contractor to have the unit serviced.

European Products for Building Tight Homes

Posted on March 31,2015 by user-756436 in air sealing

A new distributor of building products from Europe has set up shop in Brooklyn, New York. The company, called Four Seven Five, was recently founded by a trio of Passivhaus consultants: Floris Keverling Buisman, Sam McAfee, and Ken Levenson. Four Seven Five plans to import air-sealing products and ventilation fans from Germany, as well as HVAC equipment from Denmark.

One Fine Day With a Ventilation Expert

Posted on March 31,2015 by CarlSeville in ERV

I had the pleasure of attending an all-day seminar in Atlanta recently by Gord Cooke, one of the rock stars of the building science community. I have known him for a while and heard him speak a few times in the past, but was unaware of his close connection with the ventilation industry.

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