@kev-m it's going to be basically impossible for an assessor to actually do that. They'd never be able to check. Especially when they are inspecting all the other storm damage and house damp claim.

As long as you didn't say "oh we didn't follow the specification" you would be fine - in my opinion

Posted by: @batalto

@editor I should imagine that damage to your property from lack of heating would be covered by your insurance as its "storm damage" in that scenario. I am sure they might try to argue differently, however if the power goes down it doesn't matter what heating system you have - your pumps wont be working so they would all potentially suffer the same fate.

This is something we covered in our interview with Bean Beanland, head of the Heat Pump Association - our insurance policy, underwritten by AXA if memory serves me correctly, has an exclusion for heat pumps. They don’t cover them irrespective of the damage or how it occurred.

I started a thread for this here: https://renewableheatinghub.co.uk/forums/renewable-heating-air-source-heap-pumps-ashps/heat-pumps-and-home-insurance-are-you-insured#post-2282

Posted by: @editor

Posted by: @batalto

@editor I should imagine that damage to your property from lack of heating would be covered by your insurance as its "storm damage" in that scenario. I am sure they might try to argue differently, however if the power goes down it doesn't matter what heating system you have - your pumps wont be working so they would all potentially suffer the same fate.

This is something we covered in our interview with Bean Beanland, head of the Heat Pump Association - our insurance policy, underwritten by AXA if memory serves me correctly, has an exclusion for heat pumps. They don’t cover them irrespective of the damage or how it occurred.

I started a thread for this here: https://renewableheatinghub.co.uk/forums/renewable-heating-air-source-heap-pumps-ashps/heat-pumps-and-home-insurance-are-you-insured#post-2282

I just checked our home insurance and they don't cover heating systems - full stop. Doesn't differentiate between gas, electric, heat pumps, nothing.

Interesting subject. 

You will lose some efficiency by having Glycol in the system. Pure water has a better specific heat capacity that a water/glycol mix. Its not massive but every little helps!

I think if your heat pump is a monoblock unit with all the refrigerant in the outdoors unit and water being pumped outside of house to the heat pump then the risk of freezing are significantly higher.

If the heat exchanger is inside the house then the fabric of the house would have to go below 0 which is pretty unlikely except in extreme scenarios such as no power for days combined with consistent freezing temperatures. But then all other pipes in your house would probably have frozen anyway.

Posted by: @adam-c

Interesting subject. 

You will lose some efficiency by having Glycol in the system. Pure water has a better specific heat capacity that a water/glycol mix. Its not massive but every little helps!

I think if your heat pump is a monoblock unit with all the refrigerant in the outdoors unit and water being pumped outside of house to the heat pump then the risk of freezing are significantly higher.

If the heat exchanger is inside the house then the fabric of the house would have to go below 0 which is pretty unlikely except in extreme scenarios such as no power for days combined with consistent freezing temperatures. But then all other pipes in your house would probably have frozen anyway.

Excuse my ignorance but I was under the impression that all heat pumps, with their heat exchanger, were fitted outside? Are there some that are inside the building?

@scratchyman 

Monobloc have the heat exchanger within the outside unit. Split systems have the heat exchanger indoors, often called a 'Hydrobox'. GSHP's can be installed indoors or in the garage or a similar location.

@scratchyman Mine is a Daikin split system, with the fan (and compressor, I now learn) in the outside unit, there are refrigerant pipes going from that into the house. They go into the indoor unit (which houses the pump and heat exchanger).

Thanks all. You learn something new every day. So now I have to decide whether to top up our antifreeze in our Mitsubishi system, or stick with using their "freeze sat" function, which runs the pump to stop the system freezing up.

My installer has not yet added Glycol to the system yet but something just caught my eye in the Daikin manual as to why Glycol should not be added:

"For safety reasons, it is not allowed to add ethylene glycol to the water circuit. Adding ethylene glycol might lead to contamination of the domestic water if a leakage would occur in the heat exchanger coil"

Pretty obvious when you think about it, corrosion in the DHW cylinder coils will spill out Gycol into the DHW supply.   I am glad they haven't added it to my monobloc system yet!

That does pose an issue where there is a power cut in a deep freeze storm (very very rare in the SE of England).  The backup heater would not work so the system would freeze and expansion could damage the pipework.   The only other circumstance would be going on holiday in winter and switching off the HP - maybe wrap it in a blanket and tarp in that case.

@saf1973 

the glycol you add to heating circuits isn't ethylene glycol for that reason; it's propylene glycol like this

https://fernox.com/product/heat-pump-hp-5-25-litre/

Ethylene glycol is for cars and is indeed very toxic to humans and animals. 

Whether you need glycol or not in the UK is another discussion. One thing to point out is that it is expensive; you're talking 00s of £ to charge up a heating system.

I have glycol because that's what the supplier left me with.  If you don't have it your ASHP will have to be set to its antifreeze mode, which will make sure the water stays above a certain temperature even when the heating is off.  The danger then as you say is a prolonged power cut and freezing temps.       

So different manufacturers have different requirements. Daikin say don’t add glycol, Mitsubishi say you can but you don’t have to. We have had ours running the Mitsubishi freeze stat function while we work out what to do and the biggest issue we have, is that the circulation pump will run constantly when the outside temperature is less than 5C. There is a constant hum all night (and day if temp is low). The other big issue I have with Mitsubishi is that their technical help department don’t seem to know how these systems work. I have been given incorrect information over the last 2 weeks.

@scratchyman 

Do Daikin say don't add glycol or don't add ethylene glycol?

With your Ecodan, you need to choose. No glycol and freeze stat, no freeze stat and glycol, leave the heating on all the time or just take a chance.  Actually, can you change freeze stat to come on at a lower temp than 5C?  BTW as well as running the circulation pump, the ASHP will kick in to heat the water up a bit if it falls below a certain temp. 

I have glycol and use freeze stat but I think I'll turn freeze stat off now I've thought about it.  The noise of the pump doesn't actually bother us and it hardly uses any power.