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How Heat Pump Tumble Dryers Get Rid of Water

heat pump tumble dryer controls

There are three types of tumble dryer – vented, condenser, and heat pump. Now, all of these dryers work in much the same way, by tumbling clothes around inside a drum. The drum circulates warm air, which helps to dry fabrics, and the moist air is expelled by different means.

Heat pump dryers are more energy-efficient, and with rising fuel costs, this would be your pick for saving money on electricity bills.

Let’s take a look at how heat pump dryers work, in comparison to vented and condenser dryers.

Vented Dryers

We’ll start by discussing the original, and most common tumble dryer type – vented.

The way these dryer works is quite simple, making them the cheapest style of dryer you can buy.

Vented tumble dryers draw in air that is heated by an electrical heating element, blown through the laundry to extract moisture from fabrics, then the humid air is sent outside the building through exhaust ducting or piping.

The exhaust air hose should not be less than 10cm wide to limit any back pressure, so the system needs to be set up correctly for the dryer to work efficiently. To discharge the exhaust air outside, the hose either needs a separate vent through a wall, open window or door.

The only real drawback of these dryers is that they need to be used where there is good external ventilation, which can be tricky in flat and small homes.

Condenser Dryers

The condenser dryer differs from the exhaust air dryer in that the airflow for drying the laundry circulates in a largely closed circuit, eliminating the need for external ventilation.

The warm, moist air from the drum first passes through a lint filter, then through a condenser that cools the air to create condensation. The condensed water is then collected in a built-in water tank.

Thanks to this largely closed air circuit, the condenser dryer does not need a vented exhaust air hose and is therefore more can be stored in large cupboards, or rooms will little ventilation.

The condenser draws air from the installation room for cooling. The heat gained is released back

Because condenser dryers blow warm air back into the room, in winter, this can be helpful as a way to heat your home. In summer, however, it can be very uncomfortable running this type of dryer. And during the warm summer months, because condenser dryers work better when the room temperature is cooler, the dryer needs to work harder and is less energy efficient compared to vented dryers.

Heat Pump Dryers

Heatpump dryer drum

Now heat pump dryers are not affected by the ambient air temperature, because there work in a closed air system that refrigerates and heats the air as required, for optimal drying performance.

Here’s how it works: There is no heating element, instead, air is drawn into the system and is heated by compressing Freon gas in a closed circuit. This heated air is then pumped into the spinning drum where it meats clothes, extracting moisture and creating a water vapour.

Moist air is then pumped out of the drum and down into a heat exchanger, where it’s cooled by a refrigerated element, forming condensed water droplets on plates.

After removing the moisture from the air, the air then flows through a heater where it’s re-heated and pumped back into the drum, and the drying cycle continues.

So where does the moisture go? With heat pump dryers, extracted moisture gets either pumped into a water reservoir tank, where you can empty it when it’s full, or you can plump this machine into your home’s drain pipework, just the same as you can with a washing machine or dishwasher.

The heat pump itself is driven by a small electric motor. The energy savings result from the fact that the power consumption of the motor is less than the heat output generated. In addition, no energy is lost. As a result, the heat pump dryer requires around 50% less electricity compared to a conventional condensation dryer and isn’t affected by fluctuating room temperatures.

Further, this heat pump system is much more robust and has a longer life expectance over vented and condenser models.

While the vented air dryers are not as popular these days, most people opt for condenser dryers, as these dominate the market with much greater range and availability. But the tumble dryer with a heat pump is a better system, although, more expensive (expect to pay £500 or more for a good one), it will pay for itself in lower energy consumption and fewer repairs.

Heat Pump Dryer FAQ’s

How to care for a heat pump dryer?

Condensation dryers and heat pump dryers have a lint filter and an onboard condensed water tank. The dryer can only work efficiently if both are emptied and cleaned regularly. Typically, you’ll find the condensed water container is located in a pull-out drawer on the top left of the dryer. The lint filter can be pulled out at the lower edge of the drum when the door is open.

Do Siemens and AEG heat pump dryers have differences?

These tech brands have an excellent range of heat pump dryers. With regard to the basic functionality of AEG or Siemens heat pump dryers, we cannot tell you any noteworthy differences, they do much the same job. Almost all heat pump dryers from well-known manufacturers of household appliances will achieve comparable results.

Miele and Bosch have a range of premium heat pump dryers, and like Siemens and AEG, they all do the same job. However, some of the energy ratings may differ, so if you’re switching to heat pumps primarily for the eco-benefits, then compare energy ratings before purchase.

Aside from energy running costs, look at program features, dimensions and machine aesthetics to make your final decision.

How to connect the heat pump dryer to drain?

In terms of functionality, a heat pump dryer with a drain hose has the advantage that there is no need to empty the condensate container, which means minimal maintenance. It’s very simple to connect the hose, providing you have a connection to the drainpipe under the sink. It’s connected in the same way a washing machine hose connected to the plumbing.

If you already have dishwasher and washing machine drain hoses plumbed in you may not have space from the heat pump hose, which will require some adaptations to be made to the pipework.

The best way to proceed when connecting the heat pump dryer to the water drain can be found in the manufacturer’s instructions, as there are differences between the various brands.