We’re looking into getting an ASHPPunches advice to people lookimg to get an ASHP.
We’re looking into getting an ASHP but I’m unsure of the capacity of our current Vaillant ecoMAX pro boiler as all our installation and other
manuals are for 18 and 28kW boilers which I believe are the same
externally.
There are no easily accessible ID plates but I do have the serial number that’s been copied into the installation guide.
Before I go bothering Vaillant on the phone does anyone know how to ID our boiler? FWIW, ours is a 5 bedroom house from the early 70s so I’m guessing it’s *probably* the 28kW but I could be wrong.
Theo
(whose ASHP works just fine, for the record. Nice and warm all year round, for less we spent being barely warm on oil)
Theo <theom+news@chiark.greenend.org.uk> wrote:
[…]
Theo
(whose ASHP works just fine, for the record. Nice and warm all year round, >> for less we spent being barely warm on oil)
Is that comparing like for like, such as ‘oil boiler +
some insulation’ with ‘ASHP with the same insulation’,
or with ‘ASHP + lots of new insulation’?
There is a vaillant air source heat pump Facebook group which you would do well to spend some time reading. To achieve similar comfort conditions at reasonable running cost you WILL have to alter your lifestyle. You WILL
have to run your radiators at much lower (40 degree) temperatures than
with your boiler thus normally requiring swapping out for larger sizes
which may also require pipe changes. You will find a massive problem with ongoing maintenance of the external unit refrigerant containing section
and discover there are huge numbers of throw it in and run cowboys who somehow have become "registered" with mcs but when push comes to shove
don't expect help from them. If you do pursue swapping to a heat pump
check out the installation company on trustpilot and believe the bad
reviews more than the good ones.
Theo <theom+news@chiark.greenend.org.uk> wrote:
[…]
Theo
(whose ASHP works just fine, for the record. Nice and warm all year
round, for less we spent being barely warm on oil)
Is that comparing like for like, such as ‘oil boiler +
some insulation’ with ‘ASHP with the same insulation’,
or with ‘ASHP + lots of new insulation’?
Tim+ <timdownieuk@yahoo.co.youkay> wrote:
We’re looking into getting an ASHP but I’m unsure of the capacity of our >> current Vaillant ecoMAX pro boiler as all our installation and other
manuals are for 18 and 28kW boilers which I believe are the same
externally.
There are no easily accessible ID plates but I do have the serial number
that’s been copied into the installation guide.
Before I go bothering Vaillant on the phone does anyone know how to ID our >> boiler? FWIW, ours is a 5 bedroom house from the early 70s so I’m guessing
it’s *probably* the 28kW but I could be wrong.
Your boiler is almost certainly oversized so the size is irrelevant really.
In the depth of winter does it run continuously or does it cycle on and
off (assuming you have the heating on for a long time, not running it for an hour here or there)? If it cycles, then it's oversized.
Do a heat loss calculation and that'll tell you what size you actually need.
Assuming you want the ASHP to do hot water too, work out what size cylinder you have / want and then you can calculate the time to heat it with a given size of heat pump.
Theo
(whose ASHP works just fine, for the record. Nice and warm all year round, for less we spent being barely warm on oil)
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
[…]
Theo
(whose ASHP works just fine, for the record. Nice and warm all year
round, for less we spent being barely warm on oil)
Is that comparing like for like, such as ‘oil boiler +
some insulation’ with ‘ASHP with the same insulation’,
or with ‘ASHP + lots of new insulation’?
Identical amounts of insulation, which is crap tbh - 80/100mm of fibreglass loft insulation, but the loft is only a crawlspace so putting more in would make it impossible to crawl. Redoing that lot with PIR is on the todo list but it's such a PITA to access.
Thanks for that.
With such a difference in costs and effectiveness between oil and ASHP, I’m tempted to ask what was wrong with the oil-fired set-up!
As regards the loft insulation, could you get a man in to spray-insulate
it? I’ll get my coat…
Theo <theom+news@chiark.greenend.org.uk> wrote:
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
[…]
Theo
(whose ASHP works just fine, for the record. Nice and warm all year
round, for less we spent being barely warm on oil)
Is that comparing like for like, such as ‘oil boiler +
some insulation’ with ‘ASHP with the same insulation’,
or with ‘ASHP + lots of new insulation’?
Identical amounts of insulation, which is crap tbh - 80/100mm of fibreglass >> loft insulation, but the loft is only a crawlspace so putting more in would >> make it impossible to crawl. Redoing that lot with PIR is on the todo list >> but it's such a PITA to access.
Thanks for that.
With such a difference in costs and effectiveness between oil and ASHP, I’m tempted to ask what was wrong with the oil-fired set-up!
As regards the loft insulation, could you get a man in to spray-insulate
it? I’ll get my coat…
You'd do well to get an installer who is Heat Geek certified. They know their stuff and you're likely to get an install that is properly designed.
The Skill Builder Youtube channel is run by a guy who is a heat pump
skeptic, and there's an interesting series of videos between him and the guy who runs Heat Geek. The current series has them look at a botched install
by a fly by night company,
Theo <theom+news@chiark.greenend.org.uk> wrote:
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
[…]
Theo
(whose ASHP works just fine, for the record. Nice and warm all year
round, for less we spent being barely warm on oil)
Is that comparing like for like, such as ‘oil boiler +
some insulation’ with ‘ASHP with the same insulation’,
or with ‘ASHP + lots of new insulation’?
Identical amounts of insulation, which is crap tbh - 80/100mm of fibreglass >> loft insulation, but the loft is only a crawlspace so putting more in would >> make it impossible to crawl. Redoing that lot with PIR is on the todo list >> but it's such a PITA to access.
Thanks for that.
With such a difference in costs and effectiveness between oil and ASHP, I’m tempted to ask what was wrong with the oil-fired set-up!
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
[…]
Theo
(whose ASHP works just fine, for the record. Nice and warm all year >>>>> round, for less we spent being barely warm on oil)
Is that comparing like for like, such as ‘oil boiler +
some insulation’ with ‘ASHP with the same insulation’,
or with ‘ASHP + lots of new insulation’?
Identical amounts of insulation, which is crap tbh - 80/100mm of fibreglass >>> loft insulation, but the loft is only a crawlspace so putting more in would >>> make it impossible to crawl. Redoing that lot with PIR is on the todo list >>> but it's such a PITA to access.
Thanks for that.
With such a difference in costs and effectiveness between oil and ASHP, I’m
tempted to ask what was wrong with the oil-fired set-up!
Hard to generate your own oil. Electricity from solar panels is a lot easier.
Tim
Theo <theom+news@chiark.greenend.org.uk> wrote:
Tim+ <timdownieuk@yahoo.co.youkay> wrote:
We’re looking into getting an ASHP but I’m unsure of the capacity of our
current Vaillant ecoMAX pro boiler as all our installation and other
manuals are for 18 and 28kW boilers which I believe are the same
externally.
There are no easily accessible ID plates but I do have the serial number >>> that’s been copied into the installation guide.
Before I go bothering Vaillant on the phone does anyone know how to ID our >>> boiler? FWIW, ours is a 5 bedroom house from the early 70s so I’m guessing
it’s *probably* the 28kW but I could be wrong.
Your boiler is almost certainly oversized so the size is irrelevant really.
I’ve come around to that idea too. Decided that gas consumption over the year is probably a more useful measure.
In the depth of winter does it run continuously or does it cycle on and
off (assuming you have the heating on for a long time, not running it for an >> hour here or there)? If it cycles, then it's oversized.
Do a heat loss calculation and that'll tell you what size you actually need. >>
Assuming you want the ASHP to do hot water too, work out what size cylinder >> you have / want and then you can calculate the time to heat it with a given >> size of heat pump.
Less fussed about water heating. It’s only costing 35p a day on cheap rate power at present. Designing the system around the hot water requirements rather than the house heating needs seems an odd way to do things if one’s interested in optimum efficiency.
Theo
(whose ASHP works just fine, for the record. Nice and warm all year round, >> for less we spent being barely warm on oil)
That can’t possibly be true. TNP has spoken otherwise. ;-)
Precious few of them in Scotland and the nearest “heat geek verified” one hasn’t ever got back to us to quote. Our local heat geek certified fitter quoted over £25,000. Don’t think he wanted the job.
Theo <theom+news@chiark.greenend.org.uk> wrote:
John J <johnjessop46@gmail.com> wrote:
There is a vaillant air source heat pump Facebook group which you would do >>> well to spend some time reading. To achieve similar comfort conditions at >>> reasonable running cost you WILL have to alter your lifestyle. You WILL >>> have to run your radiators at much lower (40 degree) temperatures than
with your boiler thus normally requiring swapping out for larger sizes
which may also require pipe changes. You will find a massive problem with >>> ongoing maintenance of the external unit refrigerant containing section
and discover there are huge numbers of throw it in and run cowboys who
somehow have become "registered" with mcs but when push comes to shove
don't expect help from them. If you do pursue swapping to a heat pump
check out the installation company on trustpilot and believe the bad
reviews more than the good ones.
You'd do well to get an installer who is Heat Geek certified. They know
their stuff and you're likely to get an install that is properly designed. >> The MCS certification is about 'quality' but more of a box ticking exercise >> rather than teaching people about the fundamentals of good system design.
Precious few of them in Scotland and the nearest “heat geek verified” one hasn’t ever got back to us to quote. Our local heat geek certified fitter quoted over £25,000. Don’t think he wanted the job.
Tim
An early 70's house (detached?) will have almost no effective
insulation at all, except perhaps a thin layer of loft
insulation. It may have had replacement DG during its
lifetime, and some more loft insulation, but it will be the
heatloss through the walls and (?solid) ground floor that is
the issue.
A combination of cavity wall insulation (to stop air movement
inside the cavity) as well as external wall insulation is probably
the thing to spend your money on. The original house will have
a cavity that is only 50mm or 65mm, so filling that will only
offer marginal improvement (unless there is significant air
movement through the cavity). In Scotland there is the issue
of driving rain, so cavity insulation on its own might have
unexpected downsides. Adding external wall insulation as well
will add a new external rain skin because of the extra
render.
That leaves the (?solid) ground floor which might be fixable
but that involves digging out the screed and replacing with
PIR between battens screwed into the slab and a new timber
floor. If the screed has sufficient depth then you might be
able to consider underfloor heating but this is highly
disruptive and costly, unless you can diy it. External wall
insulation would only need outside pipework to be relocated.
Andrew <Andrew97d@btinternet.com> wrote:
An early 70's house (detached?) will have almost no effective
insulation at all, except perhaps a thin layer of loft
insulation. It may have had replacement DG during its
lifetime, and some more loft insulation, but it will be the
heatloss through the walls and (?solid) ground floor that is
the issue.
It is highly likely that a 70s house will have had cavity wall insulation installed by now, in the 90s if not before.
A combination of cavity wall insulation (to stop air movement
inside the cavity) as well as external wall insulation is probably
the thing to spend your money on. The original house will have
a cavity that is only 50mm or 65mm, so filling that will only
offer marginal improvement (unless there is significant air
movement through the cavity). In Scotland there is the issue
of driving rain, so cavity insulation on its own might have
unexpected downsides. Adding external wall insulation as well
will add a new external rain skin because of the extra
render.
Just doing a cavity fill isn't perfect, but a lot better than nothing - much more than marginal.
An unfilled cavity wall has a U value of about 1.6, when filled it's about 0.3. So reduces the heat loss by 80%.
That and loft insulation are the easiest and cheapest to do, if you
haven't if you haven't already.
Theo <theom+news@chiark.greenend.org.uk> wrote:
Spike <aero.spike@mail.com> wrote:
There are a number of firms that specialise in cavity-wall insulation
removal, which isn’t a cheap exercise, and there’s also the Cavity
Insulation Victims Alliance who try to get some form of justice for
sufferers of mis-sold CWI.
CWI is not a universally-acceptable procedure.
Agreed it's not an panacaea, but I'd have thought a 1970s brick+block construction would be relatively uncomplicated? It's not into lime mortar and breatheable paints territory.
I did see a map somewhere that showed that large parts of the UK were unsuitable for CWI due to the threat posed by heavy driving rain. IIRC the whole of Wales and the South West were one such area.
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
Spike <aero.spike@mail.com> wrote:
There are a number of firms that specialise in cavity-wall insulation
removal, which isn’t a cheap exercise, and there’s also the Cavity >>>> Insulation Victims Alliance who try to get some form of justice for
sufferers of mis-sold CWI.
CWI is not a universally-acceptable procedure.
Agreed it's not an panacaea, but I'd have thought a 1970s brick+block
construction would be relatively uncomplicated? It's not into lime mortar >>> and breatheable paints territory.
I did see a map somewhere that showed that large parts of the UK were
unsuitable for CWI due to the threat posed by heavy driving rain. IIRC the >> whole of Wales and the South West were one such area.
I'd have thought that could be addressed by sealing the bricks from the outside, so there's no water penetration by the rain. A lot of properties
in eg Wales and Scotland are painted or rendered which takes care of the sealing.
This is Ireland, which is known for being moist: https://www.nsai.ie/images/uploads/certification-agrement/IAB050222.pdf
"3.5.2.1.2 Severe Exposure
Severe exposure to wind-driven rain applies in
districts where the driving rain index is
5m²/sec/year or greater (see Figure 2).
In severe exposure areas the type of outer leaf
masonry finish where the Rockwool Blown Cavity
Wall Insulation System is suitable is:
* Impervious cladding and rendered walls with a
minimum cavity width of 50 mm and up to
12m in height.
* Walls must be in a good state of repair with
no evidence of frost damage and no evidence
of damage which would cause water ingress.
Unrendered brickwork is not suitable for full-fill
cavity wall insulation in the severe exposure
zones"
(in other words, sounds like the usual story of cowboy installers and then ambulance-chasing removals firms)
Theo <theom+news@chiark.greenend.org.uk> wrote:
Just doing a cavity fill isn't perfect, but a lot better than nothing - much
more than marginal.
An unfilled cavity wall has a U value of about 1.6, when filled it's about 0.3. So reduces the heat loss by 80%.
That and loft insulation are the easiest and cheapest to do, if you
haven't if you haven't already.
There are a number of firms that specialise in cavity-wall insulation removal, which isn’t a cheap exercise, and there’s also the Cavity Insulation Victims Alliance who try to get some form of justice for
sufferers of mis-sold CWI.
CWI is not a universally-acceptable procedure.
Spike <aero.spike@mail.com> wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
Just doing a cavity fill isn't perfect, but a lot better than nothing - much
more than marginal.
An unfilled cavity wall has a U value of about 1.6, when filled it's about >>> 0.3. So reduces the heat loss by 80%.
That and loft insulation are the easiest and cheapest to do, if you
haven't if you haven't already.
There are a number of firms that specialise in cavity-wall insulation
removal, which isn’t a cheap exercise, and there’s also the Cavity
Insulation Victims Alliance who try to get some form of justice for
sufferers of mis-sold CWI.
CWI is not a universally-acceptable procedure.
Agreed it's not an panacaea, but I'd have thought a 1970s brick+block construction would be relatively uncomplicated? It's not into lime mortar and breatheable paints territory.
Theo <theom+news@chiark.greenend.org.uk> wrote:
I'd have thought that could be addressed by sealing the bricks from the outside, so there's no water penetration by the rain. A lot of properties in eg Wales and Scotland are painted or rendered which takes care of the sealing.
This is Ireland, which is known for being moist: https://www.nsai.ie/images/uploads/certification-agrement/IAB050222.pdf
"3.5.2.1.2 Severe Exposure
Severe exposure to wind-driven rain applies in
districts where the driving rain index is
5m²/sec/year or greater (see Figure 2).
In severe exposure areas the type of outer leaf
masonry finish where the Rockwool Blown Cavity
Wall Insulation System is suitable is:
* Impervious cladding and rendered walls with a
minimum cavity width of 50 mm and up to
12m in height.
* Walls must be in a good state of repair with
no evidence of frost damage and no evidence
of damage which would cause water ingress.
Unrendered brickwork is not suitable for full-fill
cavity wall insulation in the severe exposure
zones"
(in other words, sounds like the usual story of cowboy installers and then ambulance-chasing removals firms)
Ah…the map I mentioned can be found here:
<https://www.labc.co.uk/news/full-fill-masonry-cavity-walls-and-exposure-wind-driven-rain>
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