Heat Pumps

[Dustydog]

I have to ask one question

Mel cogently set out her stall, unpicked and deleted some threads restoring the status quo.
Now I see the thread had been locked.

That imo may be seen by some as under -mining Mel's actions and authority.


Why?

 

[otherclive]

Mel’s very balanced and clear # 49 reiterated her previous post which would have allowed the thread to continue, but was immediately challenged in #50 necessitating Mel to have to spell out her views once again in #51. Not surprised that the thread has been locked.

 

[trevormonty]

I've been using Air exchange HP in NZ for 23 years. Their efficiency and heat output is affected by outside temperature and climate.
Max COP is for 7C outside and 20C inside.
COP of 5 means 1kw of electricity produces 5kw of heating.

UK climate with its cold(not freezing) damp/ foggy days is worst environment they can be asked to work. At the temperature the outside radiator will go below freezing resulting in it icing up due to moist in air. Once outside temperature drops <0C, moisture in air disappears ie becomes frost so freezing of radiator isn't such problem. Once radiator freezes HP goes into reverse circle (air conditioning mode), cools inside air which heats outside radiator to defrost it. This is why they seem to stop working occasionally.

Efficiency COP drops off without side temperature, a lot HPs maybe down to COP or 1-2 below freezing, one time need most heat from them. There are models that are efficient below 0C but they aren't norm in NZ. Need to do your own research and not rely solely on installers advice.

When it comes to sizing bigger better as oversized HP won't work as hard and is less likely to freeze up on cold damp nights. Also they will heat room up lot quicker and less likely to struggle when temp is below 0C.

On paper smaller HPs have higher COP than larger models eg 3Kw(max heat output) might be 5 while 8KW is 3.5. That extra efficiency isn't any help if unit is icing up or not producing enough heat on freezing day.

Ground HP don't have these icing up or efficiency issues in freezing temperatures as heat exchanger is under ground where soil temp is well above 0C.

 

[trevormonty]

I've had excellent run from Fujitsu and Mitsubishu HPs. +15yr from all of them. Replacement of Mitsubishu was little cheaper as original piping and wiring running under house could be reused.

 

[Dustydog]

Mel’s very balanced and clear # 49 reiterated her previous post which would have allowed the thread to continue, but was immediately challenged in #50 necessitating Mel to have to spell out her views once again in #51. Not surprised that the thread has been locked.

Mel's #51 was succinct and did not get challenged. It should have rested there.

Locking threads reflects badly on PCv. No wonder the Forum is not well supported compared to others.

 

[Buckman]

I've been using Air exchange HP in NZ for 23 years. Their efficiency and heat output is affected by outside temperature and climate.
Max COP is for 7C outside and 20C inside.
COP of 5 means 1kw of electricity produces 5kw of heating.

UK climate with its cold(not freezing) damp/ foggy days is worst environment they can be asked to work. At the temperature the outside radiator will go below freezing resulting in it icing up due to moist in air. Once outside temperature drops <0C, moisture in air disappears ie becomes frost so freezing of radiator isn't such problem. Once radiator freezes HP goes into reverse circle (air conditioning mode), cools inside air which heats outside radiator to defrost it. This is why they seem to stop working occasionally.

Efficiency COP drops off without side temperature, a lot HPs maybe down to COP or 1-2 below freezing, one time need most heat from them. There are models that are efficient below 0C but they aren't norm in NZ. Need to do your own research and not rely solely on installers advice.

When it comes to sizing bigger better as oversized HP won't work as hard and is less likely to freeze up on cold damp nights. Also they will heat room up lot quicker and less likely to struggle when temp is below 0C.

On paper smaller HPs have higher COP than larger models eg 3Kw(max heat output) might be 5 while 8KW is 3.5. That extra efficiency isn't any help if unit is icing up or not producing enough heat on freezing day.

Ground HP don't have these icing up or efficiency issues in freezing temperatures as heat exchanger is under ground where soil temp is well above 0C.

It does seem that some people cannot understand that when you need the heat pump the most, air source heating does not work very well as often we have temperatures dipping well below 0C in the winter.

 

[otherclive]

In reply to Toad a caravan in the locked thread I’ve looked at a number of ASHP and cylinder service and maintenance plans from different providers and the annual price seems to be in the same ballpark as for gas boilers and cylinders. Although Octopus were very competitive but designed for systems installed by them. Scope of the plans seems similar too as do the T&Cs.

 

[Dustydog]

In reply to Toad a caravan in the locked thread I’ve looked at a number of ASHP and cylinder service and maintenance plans from different providers and the annual price seems to be in the same ballpark as for gas boilers and cylinders. Although Octopus were very competitive but designed for systems installed by them. Scope of the plans seems similar too as do the T&Cs.

Putting pounds to text

According to Checkatrade, the average air source heat pump service will cost between £150 and £300. However, with HomeServe you can arrange annual servicing for your air source heat pump from just £15 a month—offering you reliable maintenance at more manageable cost.19 Nov 2024
The service excludes consumables eg filters etc

 

[Sam Vimes]

I have to ask one question

Mel cogently set out her stall, unpicked and deleted some threads restoring the status quo.
Now I see the thread had been locked.

That imo may be seen by some as under -mining Mel's actions and authority.


Why?

Mel and I discussed this and agreed to lock it.