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Cooling and Dehumidifying With A High Velocity System (SpacePak) and HRV

Compass_Property | Posted in Energy Efficiency and Durability on

I’m mid-project on a 2000 sq ft addition to an existing Victorian in Toronto, Canada.

For all intents and purposes the 2nd and 3rd floor addition are independent of the main and basement below. We have radiant floors off a HE boiler. Very tight house with R30 walls and R60 roof.

For a variety of reasons we’ve elected to cool using a spacepak and heat pump. There is an independent HRV going from bathrooms to bedrooms.

My questions are:

– If I size the cooling to right at my heat gain calculation (or even a touch under) can I add a dehumidifier to help the system out on the design days and be more efficient on the shoulder days when dry is all the comfort we need.

– Can I introduce the dehumidification to my HRV ducting where it will run more hours and reduce the need to run my heat pump or air handler.

Any advise is greatly appreciated.

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  1. GBA Editor
    Martin Holladay | | #1

    While a dehumidifier will reduce the latent load on an air conditioner, it will increase the sensible load. I'm not sure whether there is any net gain (in terms of reducing the load on your air conditioner).

    If the weather is humid, and you feel the need for dehumidification, the best thing you can do is to run your HRV as little as possible. Ventilation introduces humid outdoor air, increasing the need for dehumidification. That's why I would be leery of tying your dehumidifier to your HRV. Ideally, you don't want to run your HRV very much on humid days.

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