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Is the cycling rate acceptable on my Ideal Logic Air 4kW air source heat pump?

 
Air Source Heat Pumps (ASHPs)
Last Post by JamesPa 5 days ago
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 Mattyb
(@mattyb)
New Member Member
Joined: 6 days ago
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Topic starter 26/02/2026 2:03 pm  

Hi all,

New to the forum but been lurking from time to time. A newbie to HP life.

Had an install of an Ideal logic air 4kw last November.Very happy with it performance... beyond expectations to be honest.

So I only know it through the colder period where I would have been maybe only getting 2or3 compressor starts over the 24hr period... Question is: now the weather is getting milder I see I'm getting into the teens with compressor starts with around 8hrs of running over 24hrs.... Is this getting to the high side?Do I need to start tweaking my weather comp for the milder weather? Efficiency is good with controller cops being between 4&5 the whole time.

Cheers,

Matt.


This topic was modified 6 days ago by Mars

   
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JamesPa
 JamesPa
(@jamespa)
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Joined: 3 years ago
Posts: 4388
26/02/2026 4:19 pm  

Im not sure from your description exactly what frequency of compressor starts you are seeing.  Here is a plot of mine at present, a bit less than one start per hour.  Mine is definitely 'good' as judged by the compressor starts vs running time over a whole season.  Anything less than 6 starts per hour is sometimes considered 'acceptable', although if it is as much as 6 it suggests a well oversized heat pump and/or that increasing system volume might be a good idea.

You cant really tweak weather comp to reduce starts without affecting the temperature of your house.  Fundamentally cycling, which is what is happening, occurs because the demand is less than the heat pumps minimum output.  Some people do advocate increasing the WC curve as a means to 'fix' this but the inevitable result (unless something else is also changed) is overheating and its unclear at least to me how that 'helps'  If you are getting a good COP then I would just leave it/keep an eye on it, particularly as this is your first season.  Its absolutely inevitable that heat pumps cycle in mild weather, and unless its particularly severe not something to worry about.

 

image

This post was modified 6 days ago 2 times by JamesPa

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.


   
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 Mattyb
(@mattyb)
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Joined: 6 days ago
Posts: 2
Topic starter 26/02/2026 7:27 pm  

@jamespa Thanks James.....not sure of frequency of cycling myself to be honest....The unit's still heating a building site yet so no time to geek out on it yet with proper monitoring....just that  noticeable change from the controller.Its only set at 19° with a 1° setback at night so could be realistically be less than 2/hr still......Is this my life now?😂

 



   
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JamesPa
 JamesPa
(@jamespa)
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Posts: 4388
26/02/2026 9:17 pm  

Posted by: @mattyb
↑

@jamespa Thanks James.....not sure of frequency of cycling myself to be honest....The unit's still heating a building site yet so no time to geek out on it yet with proper monitoring....just that  noticeable change from the controller.Its only set at 19° with a 1° setback at night so could be realistically be less than 2/hr still......Is this my life now?😂

 

In answer to the last question boilers cycle too, for the same reason, and with the same consequences.   It's a feature of heating systems, don't worry.

BTW fridges, another heat pump, also cycle!  If the cop is good there is nothing to worry about.

 


4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.


   
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