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Old 10-22-2023, 01:58 PM   #1 (permalink)
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Advice on single duct portable heat pump

I was hoping to post on EcoRenovator, but I can't get access to my old account, and registration appears to be disabled, so that forum is effectively dead to me.

New Zealand's climate is significantly different than that of most of North America. In Wellington, the outside temperature rarely strays outside the 8-20c (46-68F) range. Summers tend to be sunny and hang around 20c during the day and 15c at night. The coldest few days of winter can dip into the low single digits, but even on the coldest day of the year, it's likely to be around 12c during the afternoon and 8c at night. Dew point remains moderate year round, but humidity is high.

Historically, homes have been uninsulated, with single pane windows, and people generally wore heavy clothing inside, rather than attempt to heat them. New homes are built with modern standards, but the majority of housing stock are drafty and don't hold heat well. As someone who grew up in North America, I prefer not to be cold and damp inside my home.

I recently moved into an inexpensive apartment in the city. The walls appear to have some R value, and the windows seal reasonably well, even if they are single pane. While I could just go for minimizing infiltration and use resistive heat, the indoor humidity (and condensation) gets out of hand if you seal things up too tightly.


Yesterday, I picked up (for next to nothing) a nearly-new Goldair GCPAC120 single duct portable heat pump. I understand these portable units are fundamentally flawed, but also that they do work reasonably well in mild climates. As I understand it, they create a vacuum and pull a lot of outside air into the house, but as long as the outside temperature is above the exhaust temperature, they are still a net win. Plus, they can act as a dehumidifier, or on that rare summer day where I might want it, an air conditioner.

After reading through this thread, I haven't a clue what he was talking about most of the time.

Having not done my research beforehand, I was surprised to find the unit did not need a condensate drain when acting as an air conditioner. It does, however, need one when heating, and a condensate pump would add cost, complexity, and noise.

I'm left with a few options to explore:

1) Use the heat pump in the main living area, on the floor, and add a condensate pump. (cons: pump tubing, noise, cost, unit noise)

2) Use the heat pump in the main living area and build a platform to raise it to window height. (cons: potential eyesore, unit noise)

3) Use the heat pump in a back room, where it will be less noisy and can drain without sitting on a platform in the middle of my living room. (cons: will negative pressure allow heat to effectively reach the areas I want to heat)

X) Options 1-3, but with a second duct added, to eliminate the negative pressure.

4) Chuck the heat pump outside on a covered porch, and have it vent inside. Run it on cool when I want heat, and vice versa. (cons: no thermostat control, uncertain if I can get it to dehumidify)

I'll be taking a closer look at how the unit splits air. There's a possibility several of these may not be feasible.

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