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Alternative to ERV

Matt_VT76 | Posted in Mechanicals on

We’re building a tight house in Australia (about 1 ach 50), which is quite a novel idea over here.

There are a few suppliers of quality units here including zehnder, systemair, dantherm…for about 5-9k for the unit and about 16k for all materials including distribution ducts and registers. That’s all before installation, which is about 8k for somebody to travel a few hours to install. I haven’t found any hvac contractors that have ever installed a residential erv in my building area, so I’m quite hesitant to spend that kind of money for ventilation with no service around.

My alternative to obtain ventilation in our climate, about 68f average annual temperature with highs in the 100s fairly regularly in summer and winter nighttime lows around 50, is just two in-line fans synced with no heat recovery and just let the mini split manage the latent load with some help from a portable dehumidifier when needed. Our summers are fairly humid, but we’ll have rooftop solar if about 8kw, so even though we’d like to keep energy use as low as possible, it’ll be free during the peak cooling part of the day.

I’d love to hear thoughts on what some good options are if an erv is so expensive and there isn’t any local technicians to support.

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Replies

  1. brian_wiley | | #1

    Hello, VTexpat. How large is your house, and is it a single-story or multiple?

    1. Matt_VT76 | | #4

      Hey Brian, we’ll be in a 2 storey house that’s about 2400sqft. We’ll have good airflow between the two floors, so the plan is to skip energy recovery which shouldn’t be a huge penalty with our climate in zone 2. The extracts will be at the roof ridges and the wet areas, so we should be able to keep pretty even distribution and pull the warm moist air from the ridges to go out of the house. It’s a pitched ceiling throughout so we’ll want to keep those cathedral ceilings ventilated I think.

  2. jonny_h | | #2

    Since you're dealing with hot, humid summers and apparently pretty warm winters, maybe look at a "ventilating dehumidifier" -- not sure what brands are available there but try that search term

    1. Matt_VT76 | | #3

      Thanks Jonny, I’ve been able to find one fairly local company that does ventilating dehumidifiers.

      It’s 8k for a unit plus installation.

      After going back and forth, I think I’m going to set up ductwork that will allow an erv install if they become more cost effective over here, but until then I really like the solution from a JLC article that dumped fresh air into a buffer zone, which well have upstairs, and distributes it from there.

      https://www.jlconline.com/how-to/hvac/simple-fresh-air-for-tight-houses_o

      I think for latent load, we’ll see how we go with a portable dehumidifier in that buffer zone for now and if we have the ductwork in place can upgrade to an Erv or ventilating dehumidifier if we’re not happy with it.

      It’s just been really tricky with very few homes having any mechanical ventilation here. They’ve started to look at adding it to the building code, so that’s something.

      Matt

  3. this_page_left_blank | | #5

    16k for ducts and registers is incomprehensible to me. Are they gold plated? Seems like a decimal point got moved.

    1. rondeaunotrondo | | #6

      The cost of hvac installs of any sort continue to go up. The quoted cost of $2k to install an ERV that floats around this site is long gone. I received a quote to install a Minotair ($5k) unit for $17k installed. I’m going to duct a CERV2 myself.

    2. ktim | | #7

      Australian dollars.

      1. rondeaunotrondo | | #8

        Mine was USD. Likely more than that now.

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