Are we targeting ASHP's at the wrong market?

[JohnMo]

9 minutes ago, JamesPa said:

Somehow we need to find a way to fit ASHPs in these cases

I just said a way

 

22 minutes ago, JohnMo said:

Force manufacturers to limit temperature output in heating mode to 45, and hot water mode to 60 for all heating appliances

So a new gas appliance has the same playing field as a heat pump. I would apply those limits to ALL heat pumps also. R290 can pump out 70+ degs, but at a CoP hit so why allow it.

[Beelbeebub]

53 minutes ago, SteamyTea said:

Like the Green Deal?

(expletive deleted)ing nonsense that was.

 

The easy way to do it is via punitive legislation.

The Green deal was crap for a numner of reasons, but some sort of payback mechanism via saved money on bills isn't a daft idea. You get lower bills for no upfront money. 

 

Heck, maybe we go away from energy companies providing just gas or electric and they provide heat. You pay per kwh heat delivered. How they generate that heat is up to them - direct electric, storage heaters, gas boiler, heat pump.  Then the companies are taxed on co2 emissions per kwh delivered. The more gCo2 the higher the tax. So energy companies will be imcenticised to install and maintain an efficient system. 

[JohnMo]

Some parts of UK cities provide distributed heating systems knot many), many countries also. A new housing scheme should be built around this approach, not some ad-hoc boiler or heat pump decision.  CO2 charging mechanism already exist within the tax system and have done for a decades or so.

[JamesPa]

40 minutes ago, JohnMo said:

54 minutes ago, JamesPa said:

Somehow we need to find a way to fit ASHPs in these cases

I just said a way

Well yes but...its hardly making it easy in the scenario where your gas boiler breaks, you are banned from buying a new one, and the industry takes weeks to give you a poor quote for a replacement ASHP for which you might yet need planning permission.  We do have to try a bit harder than just legislating against things if we are to take the public with us!

 

40 minutes ago, JohnMo said:

1 hour ago, JohnMo said:

Force manufacturers to limit temperature output in heating mode to 45, and hot water mode to 60 for all heating appliances

So a new gas appliance has the same playing field as a heat pump. I would apply those limits to ALL heat pumps also. R290 can pump out 70+ degs, but at a CoP hit so why allow it.

I thing the principle is a good one (and building regulations aren't that far off now) but honestly whats wrong with 55?  Its not optimal for sure, but still gives a COP of 2.5 and probably tolerably sized radiators whereas insisting on 45 quite likely makes it impossible and totally impractical in some cases.  Also my heat pump does the legionella cycle at 70.  Obviously the COP is rubbish, but better than the immersion heater.   I grant that the need for a legionella cycle is questionable, but while many still view it as necessary and in the absence of a proper public health statement on the matter any law must provide for it.

Edited Thursday at 10:02 by JamesPa

[SteamyTea]

The requirement to supply heat 99.6% of the time could be lowered to say 80% for retrofits.

Then explain that resistance heaters pay be requires few days a year.

[JohnMo]

9 minutes ago, JamesPa said:

Also my heat pump does the legionella cycle at 70

In 99% of households this just isn't required, just heat the water to 50, it's no longer an issue anyway. Most houses run on chlorinated water (like or not), if you have an unvented system also, how does legionella get in?

 

 

15 minutes ago, JamesPa said:

honestly whats wrong with 55

Is that a real comment, add in loads of defrosts at anything approaching zero, sounds like a good system performance will prevail - NOT.

[Sparrowhawk]

21 minutes ago, JohnMo said:

In 99% of households this just isn't required, just heat the water to 50, it's no longer an issue anyway. Most houses run on chlorinated water (like or not), if you have an unvented system also, how does legionella get in?

 

Exactly. Obligatory Heat Geek article: https://www.heatgeek.com/hot-water-temperature-scalding-and-legionella/

 

I chatted unofficially to our heating engineer, looked at our hot water usage (daily turnover %), and keep our UVC with a target temperature of 47C (range 45-49).

[Beelbeebub]

Just on the subject of resistance heaters. 

 

Can't backup heaters be used to boost the temp for the few very cold days? A standard immersion adds 2-3kw, which is and additional 20% for a 10kw system. 

 

If the 10kwnis enough for 90% of the days, the additonal 20% hearing power for a few days a year, maybe, should be enough. 

 

[JohnMo]

3 minutes ago, Beelbeebub said:

standard immersion adds 2-3kw, which is and additional 20% for a 10kw

kw or more correctly kW. So say 2kW for 24 hrs is 48kWh, so a big uplift in cost. This also goes away from the statement of direct heating is rubbish.  So if everyone goes this path, grid comes to standstill on a coldish day.

[JamesPa]

37 minutes ago, JohnMo said:

59 minutes ago, JamesPa said:

Also my heat pump does the legionella cycle at 70

In 99% of households this just isn't required, just heat the water to 50, it's no longer an issue anyway. Most houses run on chlorinated water (like or not), if you have an unvented system also, how does legionella get in?

I agree you are probably right, but that's not the point.  The point is that, until there is a public health statement from the NHS to the contrary, legionella protection will inevitably be fitted/required by some, if only for liability reasons and so until we fix that it must be provided for.

 

If there were an authoritative public health statement that could change, but it can't change based on your opinion or mine, it needs someone with the relevant qualifications in the relevant position.

 

41 minutes ago, JohnMo said:

1 hour ago, JamesPa said:

honestly whats wrong with 55

Is that a real comment, add in loads of defrosts at anything approaching zero, sounds like a good system performance will prevail - NOT.

I said it's not ideal, but the world isn't ideal and to outlaw it is going too far.  There are people who quite happily run at this temperature accepting the cost trade off and it's still better for the environment than burning fossil fuel.  Not everyone lives in a well insulated new build with lots of space and money for large radiators, and if we want to get to 1.4m per year we need some flexibility for people to make informed trade offs.

[JamesPa]

13 minutes ago, JohnMo said:

kw or more correctly kW. So say 2kW for 24 hrs is 48kWh, so a big uplift in cost. This also goes away from the statement of direct heating is rubbish.  So if everyone goes this path, grid comes to standstill on a coldish day.

Based on my experience so far I would say one useful option is to switch on an electric resistance heater during recovery from defrost.  Rare and for a short period of time so cost not particularly significant.  In my own case I'd only do it at night as principally it's to reduce noise, at negligible cost because my night time tarrif is low.  We need to be careful not to rule out options to manage things in the myriad of house configurations we have.  A one size fits all approach will make the transition more difficult.

[PhilT]

35 minutes ago, JamesPa said:

Based on my experience so far I would say one useful option is to switch on an electric resistance heater during recovery from defrost.  Rare and for a short period of time so cost not particularly significant.  In my own case I'd only do it at night as principally it's to reduce noise, at negligible cost because my night time tarrif is low.  We need to be careful not to rule out options to manage things in the myriad of house configurations we have.  A one size fits all approach will make the transition more difficult.

why not just get a bigger heat pump

[Beelbeebub]

47 minutes ago, JohnMo said:

kw or more correctly kW. So say 2kW for 24 hrs is 48kWh, so a big uplift in cost. This also goes away from the statement of direct heating is rubbish.  So if everyone goes this path, grid comes to standstill on a coldish day.

Direct heating is rubbish. But so is oversizing the HP system. 

 

The MCS rules tend to oversize the HPs. There are many anecdotes (not data I know) of people being quoted much larger HPs than they probably need. Especially when they are marginal on a 10kw machine and so get bumped up to the 12 or 14kw machine which is often 2fan therefore bigger, noiser, need all the primaries up sizing etc etc. 

 

If thry could just go with the slightly smaller machine and know there is, if it gets really cold the option of easily hitting the "use direct - it costs more!" button rather than unpacking the fan heaters and those oil filled rads that might save a significant amount on install and probably won't be used as the MCS calcs assume pretty warm inside temps on the coldest night. In reality, people will probably accept their house is at 19C or 18c for the one or two nights a year it happens and never prod the button. 

 

Of course we would need some control to prevent unscrupulous installers basically fitting the cheapest system and a whacking great 9k "backup heat~" that is on all the time! 

 

And therin lies the difficulty. 

[PhilT]

Just now, Beelbeebub said:

But so is oversizing the HP system.

why exactly?

[Beelbeebub]

Just now, PhilT said:

why exactly?

Capital cost and install issues (bigger pipes, larger buffer) and poorer performance in milder conditions due to the part load in spring/autumn being too low for the HP to run effectively. 

 

The "cost" of oversizing gas boiler has always been marginal. A few hundred quid more for the unit and that's it. So we have always put much bigger boiler in than we need. 

 

With HPs the install and running costs of being too big are much higher. 

[PhilT]

Modern scroll compressor / clever software controlled heat pumps just don't suffer the cycling inefficiences of the bad old days. For me there was no difference in installation price between an 8.5 and an 11 so I went for the 11 and glad I did. It is outperforming spec on cold days by a significant margin. Compare 10% inefficiency on a mild day of say 10kWh consumption compared to 10% better efficiency on a cold day of 100kWh consumption. It's unlikely to be worse than break even over the course of the season. That's definitely what the evidence is saying for mine.

[PhilT]

On 12/01/2025 at 10:35, ProDave said:

so that would give an immediate reduction in electricity used for heating, and reduced electricity use would mean fossil fuel generation required less frequently so an indirect saving in CO2 emmissions.

and an oversize heatpump like mine working 10% more efficiently than a smaller one running flat out/less efficiently on freezing cold days will mean 10% less electricity use at the time when the grid may be well over-stretched. I don't understand why people would burden themselves with additional expense and complexity of adding heating elements, boiler hybrid setups etc. when all you need is a bigger heat pump. Imagine a family during the recent freezing cold spell, they all come down with flu or lurgy of some kind (very likely this season). The house temp needs to be increased a couple of degrees all day and night to give them all the chance to get well again. In those circumstances you need a level of headroom similar to what you got from a boiler. This is just one of the many advantages of an oversized heat pump - extension, faster DHW reheat, less defrost recovery issues etc. etc.

[Roger440]

3 hours ago, JamesPa said:

Whilst I fully sympathise with your views and would probably do this if I could, I fear that the headlines in certain parts of the press would make this politically impossible.  Just look at the confected fuss over LTNs!

 

That said you can do a lot of unpopular things near the beginning of a term of office!

 

Im beginning to think some of you are mad! Clever, but mad.

 

Unpopular headlines would be the least of your problems.

 

Lets look at reality. We double or whatever gas prices. What do we think will happen? A stampede to heat pumps?

 

Not a chance. The majority of the working population get to the end of the month with little or no money in the bank. So you have just made that significantly worse by whacking up gas prices. And then you want them to switch to a Heat pump? So anything from £2-10K lets say?

 

Hows that work?

 

The reality, they will just turn down their heating, (or burn stuff) as they simply have no other choice. Thats before we consider the wider economic impacts.

 

Personally, i wouldnt and couldnt wish that upon my fellow citizens. Clearly others have a different view.

 

Regardless, any government attemting such a thing will be out at the earliest opportunity. Fortunately, for those who have a degree of compassion, highly unlikely to come to pass.

 

[JohnMo]

There is a school of thought that ASHP should be sized at least 10% bigger than design required, just to help cope with defrosting. Living with a heat pump 100% oversized (I do) isn't an issue. You just operate as appropriate. Doing weather or batch charging, I have done both with zero issues.

 

Most situations an ASHP is designed for -3 degs. So no where near the oversizing required for the top of Scotland, where you could be designing for -10.

 

A larger heat pump also seems to bigger range of modulation than a small one from what I've seen.

1 hour ago, Beelbeebub said:

MCS rules tend to oversize the HPs

Not sure that is true. If you are air tight and can provide proof of it and proof of other improvements, not sure there is an issue. Most of the issues are down to assessors or so called designer with no clue. Or owner thinking they know better because they like a house at 16 degs. It's tax payer money (£7500) so needs to fit for purpose if you sell in two years time.

 

Then there is homeowners wanting to operate as they did with the gas boiler, short on time control over multiple zones.

 

Most the buying public really aren't ready for a heat pump, they have been fed on rubbish information for years, saying zones good, high flow temps and short operation windows are fine. So running at low flow temperature for long periods just sounds wrong (and so will be very expensive).

 

Heat pumps as currently sold, are a rich man's play thing, even after grants, the prices quoted to install are in the general daft and well beyond the general person.h.

 

Building well, in the first place, fixing issues with poor housing stock (insulation and airtightness or bulldozer) are the first fix. Second is education of installers and general population (most would have zero interest in both categories).

 

As @Roger440 pushing people into energy poverty isn't an answer.

 

Rant over

[JamesPa]

3 hours ago, PhilT said:

why not just get a bigger heat pump

I will assume that was intended to be facetious!

[JamesPa]

2 hours ago, Roger440 said:

Im beginning to think some of you are mad! Clever, but mad.

Sometimes good and practical ideas come from off the wall thinking!  

Edited Thursday at 15:40 by JamesPa

[Beelbeebub]

2 hours ago, Roger440 said:

 

Im beginning to think some of you are mad! Clever, but mad.

 

Unpopular headlines would be the least of your problems.

 

Lets look at reality. We double or whatever gas prices. What do we think will happen? A stampede to heat pumps?

 

Not a chance. The majority of the working population get to the end of the month with little or no money in the bank. So you have just made that significantly worse by whacking up gas prices. And then you want them to switch to a Heat pump? So anything from £2-10K lets say?

 

Hows that work?

 

The reality, they will just turn down their heating, (or burn stuff) as they simply have no other choice. Thats before we consider the wider economic impacts.

 

Personally, i wouldnt and couldnt wish that upon my fellow citizens. Clearly others have a different view.

 

Regardless, any government attemting such a thing will be out at the earliest opportunity. Fortunately, for those who have a degree of compassion, highly unlikely to come to pass.

 

Dont think. Anyone is suggesting doubling gas prices, at least not deliberately. They are double what they were 5 years ago just because (gestures at world.events)

 

The ratio of gas to electric is the issue and right now it is too high because of a number of policy decisions. 

 

Loadig green levies onto electricity and not gas is a choice. We should remove them from electric. Whether or not to stick them on gas is aost a separate question (the cost could come from the general taxation pool). Keeping the structure where the wholesale electric price is set by the most expensive generator (gas) is also a choice. 

 

If electricity were only 2, 2.5x gas prices then HP adoption would drive itself. 

 

[JamesPa]

43 minutes ago, Beelbeebub said:

Keeping the structure where the wholesale electric price is set by the most expensive generator (gas) is also a choice. 

Where does the 'excess' go I wonder.  Is it making electricity generation ultra profitable for those who generate (at scale) using renewables, or is it offsetting something else?  

[Crofter]

Just stumbled upon this quote from Antonio Gutierrez:

"Today, governments around the globe spend nine times more to make fossil fuels cheaper than they do on making clean energy more affordable for consumers."

 

The idea that switching from fossil to renewables will saddle future generations with higher costs is just not true. 

[Beelbeebub]

23 minutes ago, JamesPa said:

Where does the 'excess' go I wonder.  Is it making electricity generation ultra profitable for those who generate (at scale) using renewables, or is it offsetting something else?  

I assume the renewable profits. 

 

The upfront cost of renewable capacity has historically been more than fossil fuels per. MW

 

I believe it is currently around $1-2m per Mw for wind. 

 

Solar in the UK is about the same (the land costs are higher, if we had lots of desert it would be cheaper) 

 

CCGT is around (or just below) $1m per. Mw

 

But the running costs of renewables are pretty low and immune to world markets for gas etc.