The Auto mode on heat pumps allows the heat pump to decide whether to heat or cool the space, but it doesn't always know best. “Auto” mode could cause your heat pump to heat on a cool summer night or cool on a sunny fall or winter afternoon. To avoid accidentally cooling during the fall and winter, use “Heat” mode.
It's natural to think "AUTO" mode would be a more efficient setting. But if you use it, your unit runs the risk of toggling unnecessarily between heating and cooling. Your heat pump will run most efficiently when set to "HEAT" in winter and "COOL" in summer.
Generally, the auto setting will start the furnace fan about half a minute after the burner is lit. The fan is turned off about a minute after the desired temperature is reached. The main benefit of setting the thermostat to 'Auto' is that it will result in more energy efficient usage.
For best efficiency and to save money, set your thermostat at 68 degrees while you are home in the cool weather months of the year. During hot months it is best to set your thermostat to a temperature as warm as you can tolerate without discomfort.
Choose "AUTO" for energy savings and "ON" if you want constant air circulation or improved air filtration. Temperatures can soar or plummet depending on the time of year.
' To achieve an optimal balance between performance and energy usage, we recommend that you set your heat pump / air conditioner temperature between 23-26 degrees (cooling) in summer and 18-21 degrees (heating) in winter.
“Auto” mode could cause your heat pump to heat on a cool summer night or cool on a sunny fall or winter afternoon. To avoid accidentally cooling during the fall and winter, use “Heat” mode. Likewise, to avoid accidentally heating on a cool summer night, use “Cool,” “Dry,” or “Fan,” but not “Auto.”
To receive maximum benefits from your heat pump in the winter months, ensure that your remote control settings are on 'HEAT' mode and your fan speed and louver are both set on 'AUTO'. This helps your heat pump determine room conditions and operate more efficiently.
If the fan is on low or quiet setting, you will only get about 1/4 of the heat the heat pump is capable of delivering. Make sure the Fan setting is on “Auto” or “high”. Check that the Mode setting is on the “Heat” setting. If the outside temperatures are very low sometimes the heat pump will go into defrost mode.
When it comes to whether you should set your furnace fan to “on” or to “auto” in winter, the answer for me is “auto” because it's the move that has the most to do with energy efficiency. It is not, however, the only thing you can do this winter to bolster your HVAC system's energy efficiency.
The fundamental difference between the “auto” and “on” settings is that the fan runs continuously with the “on” setting, even if the heating unit shuts off. The “auto” function allows you to control how long the fan operates. Once the set interior temperature is reached, the unit and the fan stop.
You should set your thermostat to the lowest comfortable temperature for your needs. For most people, this is between 18°C and 21°C.
Avoid “Auto” mode.
In “Auto” mode, heat pumps maintain a constant temperature by alternating between the “Cool” and “Heat” modes.
The Advantages of “Auto”
Lower Utility Bills — Since the blower only runs when heat is needed when your heater is set to “AUTO,” it requires less energy than if it were set to “ON.” This can lead to lower utility bills if you can put up with slightly cooler temperatures.
Press the MODE button and select heating which is represented by the (sun) symbol. Press the (down) and (up) buttons to adjust the desired temperature. We recommend 18–22°C for a comfortable environment.
Optimal Heat Pump Settings for Summer
During the summer months, the ideal setting for your heat pump is around 78 degrees Fahrenheit (25.5 degrees Celsius) according to the US Department of Energy. This setting allows the heat pump to efficiently cool your home while reducing humidity and energy consumption.
Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.
It's recommended that your heat pump runs between 18 – 22 degrees Celsius in cooling mode during the summer to save energy. Your home won't cool down any quicker if you set the temperature lower, but your unit will work a lot harder – meaning you'll use more energy.
Heat pumps do not operate as efficiently when temperatures drop to between 25 and 40 degrees Fahrenheit for most systems. A heat pump works best when the temperature is above 40. Once outdoor temperatures drop to 40 degrees, heat pumps start losing efficiency, and they consume more energy to do their jobs.
Since the AUTO setting means the fan is only engaged when the system is on, rather than constantly blowing, AUTO is the most energy-efficient option between the two settings. This means you'll be using less energy and saving money on your electric bill by using the AUTO setting.
During the winter months it is best to allow your heat pump to run at a lower fan setting and spread heat out more evenly over a longer period of time. The reason for this is two fold: Maintaining temperature over a longer period of time is more efficient than getting a room to temperature quickly.
Generally speaking with heat pumps we would aim for a DT of 5-7°c and for gas boilers a DT of 20°c, turn up the pump if the DT is too wide and down if too narrow. Many modulating boilers automatically adjust the pump speed to target dT20, these can be quickly checked, and many have settings for refinement.