Does a full dryer use more energy than a half load?

When it comes to drying freshly washed laundry, a full load is your most energy-savvy choice because every drying cycle carries a fixed energy cost for heating up, regardless of whether you’re drying one shirt or a full load. Think of it like preheating your oven: that part costs roughly the same whether you're about to cook one pizza or two. By running one full load rather than two smaller ones, you avoid paying that fixed heat-up cost twice.

To put real numbers on it, the Bosch Series 8 9kg Heat Pump Tumble Dryer (WQG24201AU) has a 7-star Energy Rating and an annual energy consumption of 170 kWh, based on Australia's Standard Test for dryer energy ratings, which assumes once weekly use. That works out to roughly 3.27 kWh per full 9kg cycle. At an average electricity rate of $0.31/kWh, that's about $1 per full load (NOTE: actual cost can vary by your region, energy provider, time of use and choice of cycle).

Using the same logic, a 4.5kg half load might use roughly the same fixed heat-up energy (~0.8 kWh, ~$0.25) plus proportionally less energy to evaporate moisture (~1.24 kWh, ~$0.38), landing at around 2.04 kWh (~$0.63) per cycle. Worked out per kilogram, that's roughly 11.2c/kg for the full load versus 14c/kg for the half load - about 25% more expensive per item when you dry a half load instead of a full one. It’s not a lot for a single use, but doing the laundry is far from an occasional experience, and it adds up over time!

On top of that, dryers work by tumbling clothes through a current of hot air. This air needs to pass through and around the fabric to pull moisture out effectively. When you only have a few items in a large drum, more of that hot air can miss the clothes, doing less useful work per cycle.

Auto-sensing is a feature that automatically stops the cycle when your clothes are determined to be dry. Most sensor dryers use two metal strips inside the drum to measure the moisture in the fabrics as they tumble past. When the sensor detects the clothes are dry, it ends the cycle. With full loads, this can help prevent the dryer from running longer than needed, which saves energy and is gentler on your clothes. Many models, like the Westinghouse 8kg EasyCare 500 Heat Pump Dryer, use this technology to help prevent over-drying and protect your laundry.

With small loads, however, sensors can take longer to give an accurate reading. With only a handful of items in a large drum, there's less fabric passing the sensor, and a single garment can also dry unevenly, staying slightly damp at a seam or waistband while the rest is dry. To avoid ending a cycle too early, most dryers wait for several consistent dry readings before stopping rather than trusting just one. With fewer items providing those readings, it simply takes longer to conclude the laundry is dry, which can lead to over-drying and wasted electricity - another reason a full load tends to be the more energy-efficient choice.

Heat pump dryers are more energy-efficient than vented models for full loads, typically using significantly less electricity per cycle. So what about small loads? Well, just as a vented dryer has the fixed energy cost of heating its element, a heat pump dryer has the fixed cost of heating its internal components, so the small-load inefficiency is still there for both types.

The key difference is that the total electricity use for a small load tends to be lower with a heat pump dryer, simply because its overall energy use is lower to begin with. So while a half load is still less efficient than a full one for either type, the energy and financial cost of that inefficiency is generally smaller with a heat pump model.

We deliver energy-smart heat pump dryers and the rest of our 8,000+ home appliances to 95% of Australia's population, and we can usually get it to you by tomorrow (weekdays), with Appliances Online's legendary FREE delivery. Plus, we can unpack and connect it for you, for free, if you’ve got the necessary connections in place, and we’ll take your old one away for free recycling.

Check out the full range of heat pump dryers here, or if you need some pointers on choosing the best type or size for you, read our Laundry Buying Guide, call our friendly team 24/7 on 1300 000 500 or message us via the chat icon at the bottom of your screen.