FAQs

Should I use my heat pumps 24 hours a day?
Can a heat pump be programmed to operate automatically?
If I turn my heat pump up to 28°C will it heat the room faster?
What is “defrost mode”?
Why does my unit have to do a defrost cycle?
How do I know which size is best for the room I need to heat?
Can heat pumps help with condensation
Will a heat pump dehumidify
How often should I clean my heat pump?
Do they need a drain?
How are Mitsubishi Electric heat pumps quieter?
Mitsubishi’s unique quietness technology

Should I use my heat pumps 24 hours a day?

No heating appliance should be used 24 hours a day. Common sense tells you, that if you leave an appliance running the whole day, you can expect your power bill to rise. Clever use of a heat pump is using it as required. If you are not at home during the day, there is no need to run your heat pump during the day. In this situation, and with good insulation, a couple of hours in the morning and a few hours in the evening should suffice.

Can a heat pump be programmed to operate automatically?

Yes. Most heat pumps will have a 24 hour timer which allows you to program your heat pumps operation for the day.

If I turn my heat pump up to 28°C will it heat the room faster?

A heat pump should not be operated like a radiant heater. Turning your heat pump up to 28°C will not make the room warm up any faster. In fact, it will use more energy as the heat pump attempts to absorb energy to achieve this unrealistic temperature.
By setting the temperature to what is actually required, say 18-22°C in heating mode (a comfortable temperature during winter), the heat pump will respond in the most efficient way and will reach this quickly and continue to maintain it – without further adjustment. Using a timer to activate this temperature half an hour before you arrive home will mean you return to warm, cosy comfort.

What is “defrost mode”?

All heat pumps will perform a defrost cycle eventually when operating in cold winter conditions. The defrost mode removes ice build up from the outdoor unit. In defrost mode the heat pump stops heating for short periods. Some heat pump brands spend longer in defrost than others.

Why does my unit have to do a defrost cycle?

Any ice building up on the outside unit reduces airflow across it, which will reduce its efficiency.

How do I know which size is best for the room I need to heat?

Every home is as individual as its owner in its requirements, choosing the wrong size for the room you need to heat can leave you cold and cost you more in power consumption.
Insulation and building orientation are important considerations when it comes to potential heat loss. For example; an older home with less insulation will lose indoor heat far quicker than a modern well insulated home. A bigger heat pump system would therefore be needed to overcome this heat loss.

Can heat pumps help with condensation?

Yes they can. Condensation is caused by warm moist air cooling and condensing. There are two ways to stop “crying windows”. You can either remove the warm moist air (ventilation) or, you can stop it from cooling to the new “dew point” by heating it. The best option is to do both, but the problem is that in winter the fresh air (ventilation) can be very cold, and expensive to heat. Better to keep the area warm.

Will a heat pump dehumidify?

Yes. They will dehumidify in cooling mode, in summer. They will not “de-condensate” in heating mode (in winter). What they will do in winter is to keep your room (or house) above the dew point so condensation does not form. However, it is in summer when uncomfortable humidity occurs – and that’s when you can switch your heat pump to cooling.

How often should I clean my heat pump?

Cleaning your heat pump regularly ensures optimum operation by reducing unnecessary power consumption, increasing efficiency and limiting exposure to condensation. We recommend cleaning your heat pump as often as every two weeks in order to utilise its full performance.

Do they need a drain?

Yes. The indoor unit on cooling will dehumidify and the resultant water needs to be led away. That is why they are typically mounted on an outside wall. If not, a condensate pump can be used to lift the water to the ceiling to be drained out. But sometimes condensate pumps can be heard when they operate. The outdoor unit when on heating will also produce water. The amount of water produced is similar to a dehumidifier in use.

Are Mitsubishi Electric heat pumps quieter?

Mitsubishi heat pumps are subjected to rigorous testing at our confidential sound testing facility and sound ratings are then independently certified.

Mitsubishi’s unique quietness technology

Fan Design
The larger fan diameter enables the motor to run at a slower speed while maintaining the same air volume. Smaller fans have to spin faster to move more air, creating more noise as air passes over the fan tips.

Coil Design
The larger surface area of our coils enables the indoor unit to maintain a higher temperature. So less air needs to be passed across the coil to achieve the same indoor temperature and less air, means less noise.

Airflow
The larger air inlet duct allows air to flow freely, reducing noise as it leaves the heat pump. Think of whistling, it is pretty hard to whistle when your mouth is open wide, the same principle applies here.

Indoor Unit
The indoor unit casing has been designed to be robust so that minimal noise is created when operating i.e. no rattling or shaking.