My personal issue now is that MCS installers refuse to take any notice and my LPA insists on an unachievable and unnecessary noise spec.
Have you been told that you cannot have a heat pump in your property location for some reason? Does your property and outside space meet the Permitted Development criteria for an Air Source Heat Pump? And is it only size specification that makes you want to do a non MCS installation?
on another point: From a planning pout of view, there is good logic why the MCS or equivalent approval mechanism exists… whether it works or not that’s another subject.
In view of the numbers of installations envisaged the MCS route means all the regulatory expertise is contained in one outside agency. This means planning authorities do not have to have multiple in-house expertise trained up to deal with individual applications. It also means there would be consistency on best practice.
The above deliberately excludes any caveat about the quality and depth of knowledge of the individuals doing the installation.
I'm not sure what you are trying to say. Planning doesn't care about the system design, only the effect on others (ie the public good) In the case of a heat pump that's limited to noise and physical appearance which planning departments deal with all the time. 'Best practice' in system design, if regulated at all, logically falls under building regulations.
And yes my property meets the outside space and other criteria for PD and the system proposed fits the noise criterion. The reason I _need_ non-mcs is that none of the 10 or so MCS bods I have tried will fit a suitable system. The reason I _want_ non MCS is that I don't wish to be ripped off for a system that will certainly perform badly, because it's way over-sized, and which involves lots of unnecessary internal disruption to replace functioning components.
This post was modified 2 years ago 3 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.
I sat through peter's youtube, this appears to be the method he's using. a better version of what I said to monitor the fossil fuel burn - using regression fit because outside temperature varies over the period.
snip from his youtube below
this interesting bit to me is to find out how he's managed to get himself registered as MCS using a significantly different assessment method and way of working with local PH Engs.
because I might try and do the same myself!
I don't think MCS actually specifies a heat loss calculation must be done, albeit that they do provide a spreadsheet. So perhaps he convinced them his method was ok, or alternatively didn't tell them and is working within the letter of the law albeit in a way that most others aren't.
This method with half hourly smart meter data, where it exists, is surely about as robust as it gets.
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.
@jamespa Not implying anything just trying to understand your surroundings a bit better. What you’ve said confirms there’s nothing else preventing you from getting a heat pump installed. Maybe a creative MCS installer like Peter Miller is what you need.
Regarding planning and the need for additional council regulatory control:
Planning doesn't care about the system design, only the effect on others (ie the public good) In the case of a heat pump that's limited to noise and physical appearance which planning departments deal with all the time.
Planning does have a duty of care to you and whoever buys your home in the future. And Building Regulations is part of the planning process. So my point is with MCS in place ,for good or bad, there is less involvement from Building Control since the design process and HP system installation is supposed to be regulated by the MCS.
And Building Regulations is part of the planning process
No it's not they are almost completely separate. You obtain planning consent based essentially on external appearance and building regs approval based on relevant aspects of technical design. Building regulation approval does not need to come from your local planning authority, planning approval must.
This post was modified 2 years 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.
Don't forget to add a bit - at least 15% - for defrosts. And hot water. And make sure the manufacturer's 'size' is deliverable when it's actually cold outside because some aren't.
Running the gas/oil heating like this may help inform in some cases. However it wouldn't have helped me in my last two houses. The current one didn't have central heating pre-ASHP and the previous one would have struggled to make double figures at heat pump radiator temperatures.
@kev-m I didn't mean that gives you simplistically the size of the HP. I mean it gives you the heat loss of the house. The size of the HP itself of course may have to include allowance for DHW, defrosts, and of course the good old made up "Name plate rating number". the method PeterMiller is using is basically this, but better , with regression fit to readings taken with varying outside temps.
The method should still work if the flow temp has to be higher, if you can get a reasonably steady state . The house with no CH, would there have been anything that could be measured or was it wood burning or something?
It was storage heaters and I did have annual consumption. But it was hard to compare the energy used with a modern, controllable system. The heat ran out on cold days and we have 2 solid fuel burners we used to top up.
Don't forget to add a bit - at least 15% - for defrosts. And hot water. And make sure the manufacturer's 'size' is deliverable when it's actually cold outside because some aren't.
Running the gas/oil heating like this may help inform in some cases. However it wouldn't have helped me in my last two houses. The current one didn't have central heating pre-ASHP and the previous one would have struggled to make double figures at heat pump radiator temperatures.
@kev-m I didn't mean that gives you simplistically the size of the HP. I mean it gives you the heat loss of the house. The size of the HP itself of course may have to include allowance for DHW, defrosts, and of course the good old made up "Name plate rating number". the method PeterMiller is using is basically this, but better , with regression fit to readings taken with varying outside temps.
The method should still work if the flow temp has to be higher, if you can get a reasonably steady state . The house with no CH, would there have been anything that could be measured or was it wood burning or something?
It was storage heaters and I did have annual consumption. But it was hard to compare the energy used with a modern, controllable system. The heat ran out on cold days and we have 2 solid fuel burners we used to top up.
I sat through peter's youtube, this appears to be the method he's using. a better version of what I said to monitor the fossil fuel burn - using regression fit because outside temperature varies over the period.
snip from his youtube below
this interesting bit to me is to find out how he's managed to get himself registered as MCS using a significantly different assessment method and way of working with local PH Engs.
because I might try and do the same myself!
I don't think MCS actually specifies a heat loss calculation must be done, albeit that they do provide a spreadsheet. So perhaps he convinced them his method was ok, or alternatively didn't tell them and is working within the letter of the law albeit in a way that most others aren't.
This method with half hourly smart meter data, where it exists, is surely about as robust as it gets.
A typical oversized gas boiler with scalding hot radiators allows the temperature of the house (or parts of it) to be set back so that it is colder for parts of the day and warms it up relatively quickly. A lot of people (I'd say most) run their heating like this. The house might be cold for 12 or more hours per day when people are at work or asleep, with the heating off for a lot of that time and using no energy.
An ASHP that is designed so that it can just match the house's heat loss on a cold day is going to have to run 24/7, i.e. it will have to keep the house warm all the time. Isn't that going to use more energy compared with the gas CH that's off for half the day?
@cathoderay is a possible example of this with his seemingly much higher energy use with his ASHP compared to the oil boiler.
Previous energy use has a role to play but you need to be careful.
In my own case (which I admit I quote frequently, but I think it may be not unusual), two MCS surveyors got to 16kW, my calculations (based on MCS assumptions but adjusting for fabric upgrades) get to 10.5kW, and the actual measured demand at -2 is 7.5kW. Most of the time the demand sits just over 4kW. So my intention is to fit an 11kW (most likely Mitsubishi) pump, but even that is marginal at 4kW. Had the MCS brigade got their way with their 16kW+ offerings, I would be well into cycling for much of the heating season which is really quite atrocious.
In my own case (which I admit I quote frequently, but I think it may be not unusual), two MCS surveyors got to 16kW, my calculations (based on MCS assumptions but adjusting for fabric upgrades) get to 10.5kW, and the actual measured demand at -2 is 7.5kW. Most of the time the demand sits just over 4kW. So my intention is to fit an 11kW (most likely Mitsubishi) pump, but even that is marginal at 4kW. Had the MCS brigade got their way with their 16kW+ offerings, I would be well into cycling for much of the heating season which is really quite atrocious.
if it helps, I've self installed a 16kw samsung. 15kw was the MCS number for my house. I didn't have the confidence to go smaller, wish I had because I'm now sure I could have. I've got 2 months minute-by-minute monitoring (installed since end march) in which we got just enough -1C to test it properly, and of course plenty of mild. Had some setup and tuning issues as you'd expected, but with a "reasonably balanced" system, cycling issues have been minor and not impacting COP. My key point for you is , it has run stably at 3.5kw output . On the even milder days when the heat demand is below that - yes it does cycle, but IMO it doesn't matter because a) the absolute value of any negative cycling impact on COP is low, because the heat demand for that day is low to start with b) with the system setup right with a good circulation volume (which I'm sure you will be doing) the relative COP impact isn't much either.
The point being, 3.5kw is below 25% of the plated value. some graphs in this post. @william1066 has the same ASHP and is getting similar numbers. So , whilst I could have saved a bit on the smaller unit, I don't believe I am overpowered to the extent that excessive cycling will ever be an issue, so I'm ok with it. If you go with 11kw plated I'd hope you'd be stable at 2.5kw if the mitsubishi behaves anything similar to the samsung.
And Building Regulations is part of the planning process
No it's not they are almost completely separate. You obtain planning consent based essentially on external appearance and building regs approval based on relevant aspects of technical design. Building regulation approval does not need to come from your local planning authority, planning approval must.
You appear to have reinterpreted my post above! My reference to planning clearly describes a “planning authority” and “planning process”. Whereas your comments suggest I was describing a “planning department” and a “building regulations department” here is what I said
on another point: From a planning pout of view, there is good logic why the MCS or equivalent approval mechanism exists… whether it works or not that’s another subject.
In view of the numbers of installations envisaged the MCS route means all the regulatory expertise is contained in one outside agency. This means planning authorities do not have to have multiple in-house expertise trained up to deal with individual applications. It also means there would be consistency on best practice.
You then assert that building regulations is not part of the planning process.
These assertions of yours, apart from being inaccurate quotes are missing the point which was about my opinion about one of the roles of MCS.
So I’ll post it below again just for completeness.
In view of the numbers of installations envisaged the MCS route means all the regulatory expertise is contained in one outside agency. This means planning authorities do not have to have multiple in-house expertise trained up to deal with individual applications. It also means there would be consistency on best practice.
I realise ideas can be exchanged quickly and may be interpreted differently depending on an individual perspective. So in this case I just wanted to be clear on the comment I had made.
if it helps, I've self installed a 16kw samsung. 15kw was the MCS number for my house. I didn't have the confidence to go smaller, wish I had because I'm now sure I could have. I've got 2 months minute-by-minute monitoring (installed since end march) in which we got just enough -1C to test it properly, and of course plenty of mild
Thanks and noted
On another forum it has been stated, by someone who appears to know their stuff, that Samsung achieves high modulation ratio by an arguably dodgy compressor bypass trick. Inspection of their system diagram shows that they do indeed employ the trick claimed, the net result of which is the the stable operation occurs but at roughly the energy use that would have been the case had the compressor been operating at a higher energy output. I honestly don't know how much effect this has as I don't think Samsung publish cop at low output. Just a warning though.
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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