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Most people have no idea what their heat pump settings actually do. So they either blast it at maximum temperature, trying to heat the room faster (which absolutely doesn’t work and will only waste power), or they leave it on the wrong setting and wonder why they’re cold.
Direct from professionals who have been dealing with and servicing heat pumps for decades, here’s how to properly use your heat pump for the winter.
Set it to 20 to 22°C during the day. That’s it.
Here’s why: each degree above 20°C increases your power consumption by roughly 10% (20th Conference on Climate Variability and Change) So running at 24°C costs 40% more than 20°C. That difference adds up fast.
20-22°C is warm enough for most people. If you’re still feeling cold at 21°C, the problem isn’t the temperature, but it may be other issues, such as drafts, humidity, or insulation.
That myth about “it costs more to reheat the room than to leave it on all day” doesn’t hold up unless your house is perfectly sealed, double-glazed, and insulated to premium standards. For most of us living in Auckland, heat leaks out constantly, so just turn it off when you leave and set a timer to warm up an hour before you get home.
Make sure it’s on HEAT mode – this is usually shown as a sun icon on the remote.
If it’s on the wrong mode it won’t heat at all, which sounds obvious but it happens.
We highly recommend either setting the fan speed to AUTO or MEDIUM. The low fan speed will be quieter, but you also won’t be getting full heating. Fan on low gives you maybe 25% of the unit’s heating capacity, which won’t do much of anything if the weather’s seriously cold.
When you set the unit to AUTO, the unit will figure out the fan speed it needs using sensors. For most people, that’s the best setting.
High fan speed heats the room faster, but uses more energy and is louder. Use high fan speed only if you need quick heating (like when you first come home in winter). Then let it settle back to auto.
You’ll want to point the vanes downward as far as it’d go. Since heat rises naturally, you want the warm air flowing down across the floor where it rises and fills the room. It’s more efficient than pointing it sideways.
Some remotes have a swing button that makes the vanes move side-to-side continuously. That’s fine too, but downward is the baseline for winter heating.
Set it to turn on about 1 hour before you wake up in the morning, and your house will be 21°C when you get out of bed. No waking up in a cold room, and no running the heater all night for no reason.
Similarly, if you get home from work at 5 pm, set it to turn on at 4 pm. You arrive at a warm house and save the power bill from running while you’re at the office.
Most modern heat pumps will allow you to set two timers – one for morning, one for evening, so make use of them!
Some units have Eco or Smart mode that automatically adjusts based on how the room is heating. Panasonic calls theirs ECONAVI, Mitsubishi has various versions (Econo, etc.) They’re designed specifically to save power while maintaining comfort. So if you find the button on your remote, turn it on and leave it.
In very cold weather (below 0°C), your outdoor unit gets frost buildup. The heat pump automatically reverses operation briefly to melt the frost, during which the indoor unit blows cool air for 10-15 minutes. This is completely normal. Don’t panic and don’t turn it off. It’s necessary for the system to keep working properly.
Once the cycle ends, it goes back to heating. Plan these outages – they usually happen at the start of heating season in winter.
Most domestic heat pumps lose efficiency in very cold conditions. Output at 0°C is typically 80-90% of rated capacity.
If you’re in the South Island or a cold region and you want full heating capacity even in extreme cold, you need either:
Most North Island locations don’t have this problem. Auckland winters rarely hit 0°C consistently.
If your house feels damp (windows sweating, clothes clammy), your heat pump might have a DRY mode. Take advantage of it – a dry room feels warmer at the same temperature.
Dry mode removes humidity without heating aggressively. Run it for an hour or two if moisture is an issue. Once the room feels drier, switch back to heat mode.
Why does my heat pump seem to take forever to heat the room, and can I make it faster?
Heat pumps heat gradually – they’re designed for efficiency, not speed. Setting the temperature higher or cranking the fan to maximum won’t make it heat faster; it’ll just waste power. If you need quick heating when you first get home, use the high fan speed temporarily, then let it return to auto. For consistent comfort, use the timer function to have the room warm before you arrive home.
Is it bad to leave my heat pump on all day?
Only if heat is escaping constantly. In most Auckland homes, heat leaks out continuously through walls, windows, and gaps, so leaving it running while you’re away just wastes money. Turn it off when you leave and set a timer to warm the house an hour before you return. You’ll save power without sacrificing comfort when you’re home.
What’s that cool air blowing from my heat pump in the middle of winter?
That’s the defrost cycle – completely normal and necessary. When outdoor temperatures drop below 0°C, frost builds up on the outdoor unit, so the system briefly reverses to melt it. The indoor unit blows cool air for 10-15 minutes, then goes back to heating. Don’t panic or turn it off. Plan for these brief interruptions at the start of winter.
My house feels cold even though the heat pump is set to 22°C. What’s wrong?
Before blaming the heat pump, check for drafts, poor insulation, or humidity – these are usually the culprits, not the temperature setting. If the room genuinely isn’t reaching 22°C after 30 minutes of running, the unit might be undersized for the space, or there could be a fault. Call us on 0800 088 888 and we can diagnose the issue.
How often should I clean my heat pump filter, and what happens if I don’t?
Clean it monthly during winter. A dirty filter forces the unit to work 30% harder and uses 30% more power – it’s one of the quickest ways to waste money. It’s an easy five-minute job that pays for itself through lower power bills. Check your manual for exactly where the filter is located.
If your heat pump isn’t reaching set temperature even after 30 minutes of running on proper settings, something’s wrong. The unit could be undersized (in which case you need a bigger unit), or it could be a fault (in which case you need service).
Ring 0800 088 888 if you’re not sure. Varcoe’s seasoned technicians can talk you through settings or arrange a service check!
Most homeowners don’t realize they could be eligible for the Warmer Kiwi Homes grant. That’s up to $3,450 off a professional heat pump installation. Let us check if you qualify.
