Heat Pump ducted into Laundry

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ejw1234567890

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#237751 16-Jun-2018 15:35

I have new Panasonic ducted heat pump system with a spare duct. Shall I duct into the laundry to help with ventilation and drying?

We use the dryer to dry towels, sheets and many clothes, but want to place clothes drying rack in laundry as well. That is, would not be excessive amounts of moisture created.

timmmay

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#2038731 16-Jun-2018 17:43

That would work, but it seems to be a bit of a waste, since the room will be well vented and won't have clothes to dry often..

Kickinbac

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#2038814 16-Jun-2018 19:58

Is the dryer vented to outside?

Ducted systems are usually desgned to condition a whole house. As long as the laundry has a return path to the return air grilles it should be fine.

ejw1234567890

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#2038920 17-Jun-2018 08:02

Thanks for replies guys.

The dryer condenses water into a container that slides out and needs to be emptied every 3 loads. It does not produce much condensation at all. There is a small exhaust fan in the laundry but this rarely gets used anyway (i.e. the ducted hot air should not escape outside.

We already dry clothes on a rack close to the laundry anyway, so that condensation is already in the house. All we are really doing is putting the clothes rack it in the laundry increasing the drying rate.

My main concern was increased condensation into the heat pump unit.

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#2038953 17-Jun-2018 08:24

It won't work. Heat pump is not for ventilation.

Aredwood

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#2038955 17-Jun-2018 08:29

The heat pump can't remove moisture when used on heating mode. It has to switch to cooling mode to be able to reduce moisture. Same thing applies to dry mode - it needs to be cooling not heating to remove moisture. So drying clothes on the racks won't be a problem to the heatpump for heating apart from extra moisture in the air. Extra moisture is more of a problem for the heatpump when used in cooling mode. As energy has to be used to condense the moisture into liquid water.

Although since you have a condensing dryer - would you even save anything worthwhile on power drying the clothes on racks instead of just using the dryer?

Consider the airflow balancing as well. Airflow into the laundry will mean less airflow into the other rooms. Consider what would happen in summer also. Would the laundry get too much aircon compared to the rest of the house?

Kickinbac

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#2039001 17-Jun-2018 10:43

By drying clothes on a clothes rack inside you a basically putting that moisture into your home. The heat pump won’t help with moisture when heating. My recomendation is dry the clothes outside or use your drier. You’ve spent a considerable amount of money on an energy efficient appliance that you won’t use.
At worst case dry them in the laundry with the exhaust fan going. That would draw the heated air from the rest of the house to the laundry. It would be interesting to know power usage of the condenser drier vs the exhaust fan and loss of heat.

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Fred99

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#2039244 17-Jun-2018 20:15

Aredwood: The heat pump can't remove moisture when used on heating mode. It has to switch to cooling mode to be able to reduce moisture.

Yes - but as it increases the temperature, it decreases the relative humidity, with the lower RH and higher temp, then stuff *not in the dryer* dries faster.

I assume that a (ducted not condenser) dryer would be more efficient if the intake air was warmer, even if it wasn't lower (absolute) humidity Of course in a damp house, absolute humidity would increase with temperature - negating part of that.

Fred99

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#2039245 17-Jun-2018 20:22

Kickinbac: By drying clothes on a clothes rack inside you a basically putting that moisture into your home. The heat pump won’t help with moisture when heating. My recomendation is dry the clothes outside or use your drier. You’ve spent a considerable amount of money on an energy efficient appliance that you won’t use.
At worst case dry them in the laundry with the exhaust fan going. That would draw the heated air from the rest of the house to the laundry. It would be interesting to know power usage of the condenser drier vs the exhaust fan and loss of heat.

I think that depends very much on your house. We will dry clothes on a rack indoors in Chch, with heat pumps going. The clothes dry fast (faster than outdoors with the weather we've had over the past few weeks) and we don't have a condensation problem at all.

Tonight it's 8 deg C outside and 95% RH (yep - yuck) It's 20 deg inside, relative humidity is thus probably about 50%.