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gtojohn 09-24-14 10:37 PM

I use one of these when it comes time to quantify airflow and changes. I does require some averaging.
One of the biggest difficulties for diy systems would be btu measurement. I see variations in manufacturer's btu certifications on systems' output with the same condensing unit and different blower or coil options. Without the correct btu output you can't calculate seer or btu per watt.

kostas 05-15-15 09:08 AM

My DIY HRV system completed
10 Attachment(s)
Hi people, it's been a while since my last post, after many months of hard work I finished what I call the first version of my complete DIY HRV home system. As I previously said I wanted full-house ducting with outtakes in the livingroom and bedrooms and intakes in the bathrooms and kitchen. That meant lowering 13cm the whole ceiling of the first floor, some 45sqm of drywall done in aprox 10 days work there... By the way I also installed new recessed LED lighting and an also recessed VPR motorized housing with motorized screen and HT sound system. I finished the first floor last August (2014) and the rest of the ducting by February of this year. The HRV is rocking since then and, even if the winter wasn't very cold this year, the inside comfort is superb! No more window opening, no more cooking odors on the second floor, no more steamy mirror while taking showers! Last but definitely not least, you get all that fresh air during the sleep, which is priceless.
Here are some photos:

First floor plan with duct project (orange return, blue supply)

Kitchen return boots - project

Boot construction:

Distribution plenums:

Demolition man! :D

Left: corridor supply hole, right: kitchen return and livingroom supply hole.

Twin boot (kitchen return and livingroom supply) project and construction

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kostas 05-15-15 09:23 AM

10 Attachment(s)
<<<continued from previous post<<<

Twin plenum installed:

Kitchen boots installed:

Corridor duct:

Corridor duct installed on the left, VPR recessed motorized lift (DIY, of course!) and twin boot on the right, Santorini in the center :D :

Kitchen return ductwork:

Distribution plenums and drywall construction:

Cladding finished, this is the kitchen return hood:

And this is a finished view with the new lighting fixtures:

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kostas 05-15-15 09:38 AM

10 Attachment(s)
<<<continued from previous post<<<

Grilles and filters:

Livingroom grille:

Corridor supply and mixing grille:

Bathroom drywall cladding:

Bathroom return stackhead:

Stackhead installed with grille:

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kostas 05-15-15 09:51 AM

10 Attachment(s)
<<<continued from previous post<<<

Over the stairs return grille:

2nd bathroom return grille while checking air speed:

Kids bedroom supply grille:

Bedroom supply grille:

Supply and return chimneys construction (you can see the IKEA bowls I used as caps)

Roof installation:

Inside ductwork to the HRV (from bathroom and kitchen and to livingroom)

Bathrooms return plenum with spiraled tube attached to the HRV:

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kostas 05-15-15 09:59 AM

5 Attachment(s)
<<<continued from previous post<<<

To the bedrooms PAL ductwork:

The beast is on!

Arduino control board. I used 4 DHT-22 temperature and humidity sensors, one for each flow, and 6 relays for the two motors (3 for each one, one per speed)

Arduino web interface control panel:

DIY ultrasonic humidifier (dedicated post in the near future :) )

That's all for now, hope you enjoy :thumbup:

AC_Hacker 05-15-15 10:06 AM

What an awesome project!!
Amazing, inspiring project, and beautifully documented too.

Thank you for going to the trouble of posting it for all to see.

I would have to say, that I fear that the small holes you drilled in the outlet covers, might restrict the free flow of air, and may increase noise and energy cost.

Other than that, I am astounded.



Daox 05-15-15 10:10 AM

That is very impressive work! It looks great and to hear its functioning well is even better news. Thank you for sharing!

kostas 05-15-15 05:03 PM

Thanks, glad to contribute.
AC, the covers are machined punched, the two small ones are shelves from the local IKEA store and the long one (kitchen) is custom made. There are more than 3200 5mm holes in it, which is more than enough for a single inlet. Besides, the whole ductwork is actually oversized as I used 150mm (or equivalent when rectangular) for almost every branch, which could hold up up to 200 m3/h (118 cfm) within the safe range of laminar speed (that's 3m/sec) and thus virtually noise free. The actual flow of every branch is hardly 25 m3/h for everyday use, so I'm quite sure about having no unwanted turbulence.

tinco 01-12-16 10:06 AM

Hi :) This thread is great. I've been looking at the Recair premade recuperators, they're really cheap. I saw Fornax has posted pictures but they seem to have disappeared, anyone know if they're still around somewhere? I'm a forum newbie so I don't have PM rights yet to ask Fornax for them.


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