Heat Pump Pricing versus current costs

wrf12345

"High flow temperatures and unnecessary complications will result in an inefficient expensive to run set up."

So both the Samsung and the new high temp Octopus HP have been wrongly designed and should be withdrawn from the market?

Reed_Richards

These high temperature heat pumps have been designed so that they might be used as drop-in replacements for a gas or oil boiler.  If you do this, you are very likely to find that they cost more to run than the gas or oil boiler that they replaced.  I suspect Octopus customers will be offered some sort of compensatory tariff if they get the high temp Octopus HP so that they end up paying much the same, rather than more.  

DougMLancs

Their Cosy Tariff now has 8 hours at 11.2p/kWh with this in mind. The MCS calc they use (and everyone else) is notorious for overestimating heat loss with the estimated air changes. I was listening to their Head of HP sales the other day and they find it’s not uncommon to design to 50 C and then they end up dropping the flow temp to 42-45 C. MCS are revising the heat loss methodology though so hopefully this will be less of a problem in future. Personally, I’d love Octopus to have a heat pump+ option with their quotes which designs to a lower flow temp. for those who do have the funds. Now that they’ve partnered with Heat Geek though maybe they just refer those people to them? 

Reed_Richards

DougMLancs said:

I was listening to their Head of HP sales the other day and they find it’s not uncommon to design to 50 C and then they end up dropping the flow temp to 42-45 C. 

That's exactly what happened to me, temperature-wise, but there was no "they".  Installers don't come back to inspect your heat pump in the middle of winter and spend a few days in your house to find out what water temperature you really need.  If your Weather Compensation settings have been set too high then it is left entirely up to you to make adjustments.  It's a slow process of trial and error until such time as heat pumps are made "intelligent" enough that they can do a major self-adjust (in which case the second "they" in the sentence would be the heat pumps themselves).

DougMLancs said:

Their Cosy Tariff now has 8 hours at 11.2p/kWh with this in mind. 

Conventional wisdom is that you need to run a heat pump 24/7 so it's the cost of the other 16 hours that you need to factor in.  

matt_drummer

wrf12345 said:

"High flow temperatures and unnecessary complications will result in an inefficient expensive to run set up."

So both the Samsung and the new high temp Octopus HP have been wrongly designed and should be withdrawn from the market?

No.

The market for heat pumps is huge and there needs to be products that appeal to everybody.

There will be many people who cannot justify the initial cost and keeping radiators that are designed to run at 70c reduces those costs and therefore satisfies that segment of the market.

There are also many people who will be difficult to convince that just because a radiator is barely luke warm it is still putting out the same amount of heat as a smaller radiator that is too hot to touch.

These high temperature heat pumps are correctly designed to suit that segment of the market.

None of that means that heating water to 65c will be anywhere near to as efficient as heating water to 30c and therefore it will always cost more using the same heat pump. It will always use less energy to heat water to a lower temperature using the same equipment.

I haven't seen any evidence that shows that R290 heat pumps are significantly more efficient than R32 heat pumps. I know that my R32 heat pump is as or more efficient than most if not all R290 heat pumps I have seen data for.


So these high temperature heat pumps are marketed as saving the cost and inconvenience of installing bigger radiators and having the same feel as the oil and gas boilers they replace.


Even if there were advantageous electricity tariffs to cater for these heat pumps it would still be better to run at lower flow temperatures as you would still use less electricity.

DougMLancs

Reed_Richards said:

DougMLancs said:

I was listening to their Head of HP sales the other day and they find it’s not uncommon to design to 50 C and then they end up dropping the flow temp to 42-45 C. 

That's exactly what happened to me, temperature-wise, but there was no "they".  Installers don't come back to inspect your heat pump in the middle of winter and spend a few days in your house to find out what water temperature you really need.  If your Weather Compensation settings have been set too high then it is left entirely up to you to make adjustments.  It's a slow process of trial and error until such time as heat pumps are made "intelligent" enough that they can do a major self-adjust (in which case the second "they" in the sentence would be the heat pumps themselves).

DougMLancs said:

Their Cosy Tariff now has 8 hours at 11.2p/kWh with this in mind. 

Conventional wisdom is that you need to run a heat pump 24/7 so it's the cost of the other 16 hours that you need to factor in.  

My installer did. Octopus also keep in touch with all their customers post install. I run mine 24/7 too but for those who are treating it like a gas boiler still, at least it helps. Best option for any heat pump is having a small battery that can use those cheap rates for charging.

matt_drummer

I have large enough batteries to run my house from them entirely, even in the winter.

What I did have a problem with when I had an over sized heat pump was that it regularly pulled so much electricity that I would exceed the power my inverter could supply.

With my new correctly sized heat pump that runs continuously it means that we can use all the other stuff in the house at the same time as the heat pump and rarely exceed what the inverter can supply.

Not only do we use half the electricity of the old heat pump but we now rarely import outside the Cosy tariff cheap rates.

Reed_Richards

DougMLancs said:

Reed_Richards said:

DougMLancs said:

I was listening to their Head of HP sales the other day and they find it’s not uncommon to design to 50 C and then they end up dropping the flow temp to 42-45 C. 

That's exactly what happened to me, temperature-wise, but there was no "they".  Installers don't come back to inspect your heat pump in the middle of winter and spend a few days in your house to find out what water temperature you really need.  If your Weather Compensation settings have been set too high then it is left entirely up to you to make adjustments.  It's a slow process of trial and error until such time as heat pumps are made "intelligent" enough that they can do a major self-adjust (in which case the second "they" in the sentence would be the heat pumps themselves).

DougMLancs said:

Their Cosy Tariff now has 8 hours at 11.2p/kWh with this in mind. 

Conventional wisdom is that you need to run a heat pump 24/7 so it's the cost of the other 16 hours that you need to factor in.  

My installer did. Octopus also keep in touch with all their customers post install. I run mine 24/7 too but for those who are treating it like a gas boiler still, at least it helps. Best option for any heat pump is having a small battery that can use those cheap rates for charging.

Did what, exactly?  I was suggesting that it would take days of observation to make a major adjustment to the leaving water temperature settings and know that it was correct.  But you could probably accomplish this via a succession of quick visits.  Is your installer is based close to where you live?  

Reed_Richards

matt_drummer said:

I haven't seen any evidence that shows that R290 heat pumps are significantly more efficient than R32 heat pumps. I know that my R32 heat pump is as or more efficient than most if not all R290 heat pumps I have seen data for.

I read elsewhere a comment from somebody who tried to make a like-for-like comparison that an R290 heat pump is less efficient than the equivalent R32.

matt_drummer

Reed_Richards said:

matt_drummer said:

I haven't seen any evidence that shows that R290 heat pumps are significantly more efficient than R32 heat pumps. I know that my R32 heat pump is as or more efficient than most if not all R290 heat pumps I have seen data for.

I read elsewhere a comment from somebody who tried to make a like-for-like comparison that an R290 heat pump is less efficient than the equivalent R32.

Quite possibly.

I think that what is beyond doubt is heating water to 65c will not be as cheap or as efficient as heating water to 30c with our current technology.