I've been looking more closely at heat pumps again, to try and advise
someone who's living in a house with only infra-red ceiling panels and a
wood burning stove.

What I've learned so far:

1) there are a lot of sharks about using maximum efficiencies (COP) to
claim dubious payback periods. (5 year payback for an £11K net cost
system, I really can't see that, especially with rising leccy prices).

2) it's still hard to find out real info

My only experience is I had a dual purpose air-air unit about 15-20
years ago. It was great as an aircon unit but useless for heating once
the outside temp. dropped below freezing. I reckon it used to blow out
warm air about 15 degC or maybe even lower.

I recall someone recently posting about one years worth real life
experience/costs of an air-water system, but in this case there are no
existing radiators/pipes. Underfloor is out of the question.

Initially I think an air-air system would make sense for this case, but
what I can't find out is what air temperature to expect from the
internal unit.

I can see COP can be up to 5 these days, pretty good. I can also see
air-water can achieve 60-70 degC water temperature now, which is also
pretty good.

What I can't find out is what internal air temperatures (air-air system)
I could expect when say the outside temperature is -5 or hovering around 0.

Anyone got an air-air system, or know someone who's got one?

--
/Simon

siwilson <siwilson@nodamnspamn.hotmail.com> wrote in
news:k3iltnFqtkvU1@mid.individual.net:

> I've been looking more closely at heat pumps again, to try and advise
> someone who's living in a house with only infra-red ceiling panels and
> a wood burning stove.
>
>

my former housemate and good friend is the #2 at
https://pbtinstallations.co.uk/
they have been installing heat pumps for many years and Pete has gone from
a one man band to employing several people in the last decade

> What I can't find out is what internal air temperatures (air-air
> system) I could expect when say the outside temperature is -5 or
> hovering around 0.
>
> Anyone got an air-air system, or know someone who's got one?
>

give Pete a ring. He might be able to answer your query

El Fri, 27 Jan 2023 19:10:48 +0000, siwilson escribió:

> Initially I think an air-air system would make sense for this case, but
> what I can't find out is what air temperature to expect from the
> internal unit.

Air air? Do you mean aircon? We have lots of split inverter units and
when the sun's out they cost us nothing to run (solar panels). They heat
the inside really well. Apparently, they're more efficient at heating
than at cooling. No-brainer here, but then we do suffer from 40ºC summers.

--
Paul.

https://paulc.es/elpatio

Paul Carmichael <wibbleypants@gmail.com> wrote:
> El Fri, 27 Jan 2023 19:10:48 +0000, siwilson escribió:
>
>> Initially I think an air-air system would make sense for this case, but
>> what I can't find out is what air temperature to expect from the
>> internal unit.
>
> Air air? Do you mean aircon? We have lots of split inverter units and
> when the sun's out they cost us nothing to run (solar panels). They heat
> the inside really well. Apparently, they're more efficient at heating
> than at cooling. No-brainer here, but then we do suffer from 40ºC summers.

I think by "air-air system", Mr. Wilson means an air source heat pump
as opposed to a ground source heat pump.

--
FJR1300A, GL1000, KLR650A6F, EX250J9A, DR200SE, Vespa Ciao

El Sat, 28 Jan 2023 14:24:58 +0000, Mark Olson escribió:

> Paul Carmichael <wibbleypants@gmail.com> wrote:
>> El Fri, 27 Jan 2023 19:10:48 +0000, siwilson escribió:
>>
>>> Initially I think an air-air system would make sense for this case,
>>> but what I can't find out is what air temperature to expect from the
>>> internal unit.
>>
>> Air air? Do you mean aircon? We have lots of split inverter units and
>> when the sun's out they cost us nothing to run (solar panels). They
>> heat the inside really well. Apparently, they're more efficient at
>> heating than at cooling. No-brainer here, but then we do suffer from
>> 40ºC summers.
>
> I think by "air-air system", Mr. Wilson means an air source heat pump as
> opposed to a ground source heat pump.

Exactly. That's what aircon does.

"Surprisingly, we come across plenty of people who don’t realise that air
conditioning heats as well as cools air. Yet, most modern air
conditioning systems are heat pumps which means they are capable of
heating and cooling."

https://www.midlandaircon.co.uk/can-using-air-conditioning-to-heat-my-
home-save-money/

--
Paul.

https://paulc.es/elpatio

On 28/01/2023 09:39, Paul Carmichael wrote:
> El Fri, 27 Jan 2023 19:10:48 +0000, siwilson escribió:
>
>> Initially I think an air-air system would make sense for this case, but
>> what I can't find out is what air temperature to expect from the
>> internal unit.
>
> Air air? Do you mean aircon?

I mean an air-air heat pump, which usually they can work both ways, ie
heat or cool.

> We have lots of split inverter units and
> when the sun's out they cost us nothing to run (solar panels). They heat
> the inside really well. Apparently, they're more efficient at heating
> than at cooling.

Well, I'm looking for something primarily for heating, which of course
means winter, which also means pathetic amount of solar available (in
the UK at least). And a lot of additional expense too.

My wnderstanding was the reverse - better at cooling than heating.

> No-brainer here, but then we do suffer from 40ºC summers.

The problem here is finding out how good the heatpump is when the
outside temp. is low. They all quote their "best" coeffecient of
performance which is usually at higher temperatures.

On 28/01/2023 14:24, Mark Olson wrote:
> Paul Carmichael <wibbleypants@gmail.com> wrote:
>> El Fri, 27 Jan 2023 19:10:48 +0000, siwilson escribió:
>>
>>> Initially I think an air-air system would make sense for this case, but
>>> what I can't find out is what air temperature to expect from the
>>> internal unit.
>>
>> Air air? Do you mean aircon? We have lots of split inverter units and
>> when the sun's out they cost us nothing to run (solar panels). They heat
>> the inside really well. Apparently, they're more efficient at heating
>> than at cooling. No-brainer here, but then we do suffer from 40ºC summers.
>
> I think by "air-air system", Mr. Wilson means an air source heat pump
> as opposed to a ground source heat pump.
>

Yup.

--
/Simon

El Sat, 28 Jan 2023 17:16:04 +0000, siwilson escribió:

> On 28/01/2023 09:39, Paul Carmichael wrote:
>> El Fri, 27 Jan 2023 19:10:48 +0000, siwilson escribió:
>>
>>> Initially I think an air-air system would make sense for this case,
>>> but what I can't find out is what air temperature to expect from the
>>> internal unit.
>>
>> Air air? Do you mean aircon?
>
> I mean an air-air heat pump, which usually they can work both ways, ie
> heat or cool.
>
>> We have lots of split inverter units and when the sun's out they cost
>> us nothing to run (solar panels). They heat the inside really well.
>> Apparently, they're more efficient at heating than at cooling.
>
> Well, I'm looking for something primarily for heating, which of course
> means winter, which also means pathetic amount of solar available (in
> the UK at least). And a lot of additional expense too.
>
> My wnderstanding was the reverse - better at cooling than heating.
>
>> No-brainer here, but then we do suffer from 40ºC summers.
>
> The problem here is finding out how good the heatpump is when the
> outside temp. is low. They all quote their "best" coeffecient of
> performance which is usually at higher temperatures.

I know that ours "just work", ie; they heat the house, but although we're
currently suffering a horrible cold snap (from the north pole), the
lowest temperatures we're seeing are -2ºC, which is a tad higher than
those in the UK. We have also been getting between 4 and 5 kW off the
roof between 10:00 and 16:00 today.

--
Paul.

https://paulc.es/elpatio

On 27/01/2023 19:10, siwilson wrote:

> Anyone got an air-air system, or know someone who's got one?
>

No, but we did view one bungalow that had one.

They said it was very good - but they would, wouldn't they?

TBF they were very enthusiastic about it. They were rather 'green' and
'alternative' though.

--
Moto Morini 2C/375
Gilera 175 Sport, Husqvarna 401 Svartpilen
"Do not adjust your mind, there is a fault in the reality"

Paul Carmichael <wibbleypants@gmail.com> wrote:
> El Sat, 28 Jan 2023 14:24:58 +0000, Mark Olson escribió:
>> Paul Carmichael <wibbleypants@gmail.com> wrote:

>>> Air air? Do you mean aircon? We have lots of split inverter units and
>>> when the sun's out they cost us nothing to run (solar panels). They
>>> heat the inside really well. Apparently, they're more efficient at
>>> heating than at cooling. No-brainer here, but then we do suffer from
>>> 40ºC summers.
>>
>> I think by "air-air system", Mr. Wilson means an air source heat pump as
>> opposed to a ground source heat pump.
>
> Exactly. That's what aircon does.

Most people don't call traditional air conditioners heat pumps, even
though they _are_ heat pumps. The term heat pump in popular usage is
reserved for _reversible_ units that can transport heat in either
direction, not just move heat from inside the house to outside.

> "Surprisingly, we come across plenty of people who don’t realise that air
> conditioning heats as well as cools air. Yet, most modern air
> conditioning systems are heat pumps which means they are capable of
> heating and cooling."

Only if they have a reversing valve so that they can work in either
direction. Plenty of modern air conditioning systems are still being
sold that are only capable of cooling the inside of the house and not
heating it. For sure, as time goes on and the cost of reversible heat
pump systems decrease compared to A/C only systems, eventually most
whole house systems will be heat pumps. But I'm fairly sure that A/C
only units will continue to be produced unless they are outlawed.

--
FJR1300A, GL1000, KLR650A6F, EX250J9A, DR200SE, Vespa Ciao

On 28/01/2023 17:16, siwilson wrote:

>
> My wnderstanding was the reverse - better at cooling than heating.

When cooling the electricity used to run the unit is added to the warm
air expelled outside, when heating it is added to the warm air brought
inside

>
> The problem here is finding out how good the heatpump is when the
> outside temp. is low. They all quote their "best" coeffecient of
> performance which is usually at higher temperatures.
>

Most of the split units (where the refrigerant passes through the wall
in two circulation pipes) publish tables for the COP at different inside
and outside temperatures and a cursory glance suggested to me the COP
remained above 3 when delta T was under 10, so stuff all use for those
10 or so cold days we suffer in Surrey but then I am totally wood fired
so not of interest to me.

I am looking at a multi split for my daughter but retaining the gas
boiler as it will be sufficient on a day like today, will make use of
solar PV and she can still buy electricity off peak at 10P/kWh and run
all day on it. The Daiken units can also heat a water tank to ~50C with
a COP of 3, cost and payback need some thought. Tank still needs heating
to above 60 by gas or immersion once a week for hygiene.

I would avoid accepting a grant that is dependent on having the gas
connection removed permanently.

El Sat, 28 Jan 2023 19:49:39 +0000, Mark Olson escribió:
<snip>
> Most people don't call traditional air conditioners heat pumps, even
> though they _are_ heat pumps. The term heat pump in popular usage is
> reserved for _reversible_ units that can transport heat in either
> direction, not just move heat from inside the house to outside.
<snip>
> Plenty of modern air conditioning systems are still being
> sold that are only capable of cooling the inside of the house and not
> heating it.

Hang on, where are you? I've never even seen an airon unit that doesn't
heat. There's always a "mode" button on the remote.

You must be somewhere really primitive, like the USA, maybe. :-)

--
Paul.

https://paulc.es/elpatio

siwilson <siwilson@nodamnspamn.hotmail.com> wrote:
> I've been looking more closely at heat pumps again, to try and advise
> someone who's living in a house with only infra-red ceiling panels and a
> wood burning stove.

Heat pump owner here :-)

> What I've learned so far:
>
> 1) there are a lot of sharks about using maximum efficiencies (COP) to
> claim dubious payback periods. (5 year payback for an £11K net cost
> system, I really can't see that, especially with rising leccy prices).

I'm not sure 'payback' is really the thing to look at. If you need to buy a
heating system, which should you choose? You have options of gas, LPG, oil,
wood, pure electric, heat pump... They all have their pros and cons, and
different costs.

'Payback' is only a thing that matters if you are comparing against another
system, eg one you already have: if I pay X pounds upfront but it is cheaper
to run by Y pounds a year, it'll work out cheaper assuming it lasts more
than (X/Y) years. (and all your assumptions remain valid)

To calculate anything you first need to know:
a) what your annual heating demand is (in kWh).
b) what the running costs are for a system to provide that
c) how much it will cost to install that system

Energy bills will help with a), but the first step for anything is to do a
heatloss calculation for your house which will also tell you the peak
heating load (ie on the coldest average day how much heating you need) -
this is important to size your system correctly.

Also, don't forget to budget hassle factor: chopping wood or dragging
around 47kg gas bottles aren't for everyone.

> 2) it's still hard to find out real info

https://renewableheatinghub.co.uk/
(especially the forum) and
https://forum.buildhub.org.uk/forum/119-air-source-heat-pumps-ashp/
are good places. There is also a book:
https://www.amazon.co.uk/Heat-Pumps-Home-John-Cantor/dp/1785007793
which is useful for the principles, if not which one to buy.

Otherwise I'm happy to help...

> My only experience is I had a dual purpose air-air unit about 15-20
> years ago. It was great as an aircon unit but useless for heating once
> the outside temp. dropped below freezing. I reckon it used to blow out
> warm air about 15 degC or maybe even lower.

A decent unit will have a defrost cycle where it reverses to clear ice
off the evaporator - if it's designed for a warm climate maybe it didn't
defrost and iced up?

Was -5.5C on a morning last week and our air2water ASHP did just fine. I
think if you're below -20C then an electric backup heater comes in handy,
but we don't get Minnesota winters in the UK.

I can't really comment how that goes with air2air units since I've never
operated one in freezing conditions. But the Minnesota folks do (air2water
is rare in the US), and it obviously works for them.

> I recall someone recently posting about one years worth real life
> experience/costs of an air-water system, but in this case there are no
> existing radiators/pipes. Underfloor is out of the question.

That was me :) We're just on regular radiators, no UFH (although I'm
pondering putting some in when we redo the kitchen/bathroom).

If you have no pipes then air2air is worth thinking about, although you
should realise that you won't get any heat without fan noise. Water-based
systems are near silent (just the pump and an occasional bit of pipe ticking)
while some people can't cope with fan blowers.

OTOH multi-split units are cheaper to fit, where there's a wall unit in each
room. And you get cooling 'for free'. But there's no 5K Boiler Upgrade
Scheme grant.

> Initially I think an air-air system would make sense for this case, but
> what I can't find out is what air temperature to expect from the
> internal unit.

I had a look around and I couldn't see this clearly - the datasheets that do
mention temperatures are talking about outside temps (eg can cool when it's
-10C to +48C outside, but can only heat when -18C to +18C outside), with no
mention of the indoor temps.

> I can see COP can be up to 5 these days, pretty good. I can also see
> air-water can achieve 60-70 degC water temperature now, which is also
> pretty good.

Yes. The COP suffers though - the lower you can get the water temps the
more efficient it is. Mine can do 55C water but I run the hot water tank at
44C so it doesn't have to work so hard. (a timer boosts it up to 60C once a
week to zap any bugs)

> What I can't find out is what internal air temperatures (air-air system)
> I could expect when say the outside temperature is -5 or hovering around 0.

I think most a2a systems are used primarily for cooling so whole-house
heating with them isn't the primary reason to install. The above suggests
they will heat down to -18C outside, but we don't know the max output temp.
The datasheets will say something about the derating at particular outdoor
temps (eg for air2water the standard COP measure is 7C outdoors/35C water, but
when it's freezing outside the COP gets worse).

Ah, this indoor unit:
https://www.daikin.co.uk/en_gb/products/product.table.html/FTXP-N.html
the specs are at:
(1) - Cooling: indoor temp. 27°CDB, 19°CWB; outdoor temp. 35°CDB; equivalent piping length: 5m; level difference: 0m
(2) - Heating: indoor temp. 20°CDB; outdoor temp. 7°CDB, 6°CWB; equivalent refrigerant piping: 5m (horizontal)

and I think 'DB' is 'dry bulb' and 'WB' is 'wet bulb'. That would be paired
with an outdoor unit, eg:
https://www.daikin.co.uk/en_gb/products/product.table.html/ARXF-E.html

I'm not seeing COP figures there though.

> Anyone got an air-air system, or know someone who's got one?

This is interesting (and the comments):
https://heatpumps.co.uk/2021/07/21/is-a-reversible-air-air-heat-pump-a-proper-heating-system/
and it's by the author of the book above, so he knows his stuff.

Theo

Paul Carmichael <wibbleypants@gmail.com> wrote:
> El Sat, 28 Jan 2023 19:49:39 +0000, Mark Olson escribió:
> <snip>
>> Most people don't call traditional air conditioners heat pumps, even
>> though they _are_ heat pumps. The term heat pump in popular usage is
>> reserved for _reversible_ units that can transport heat in either
>> direction, not just move heat from inside the house to outside.
> <snip>
>> Plenty of modern air conditioning systems are still being
>> sold that are only capable of cooling the inside of the house and not
>> heating it.
>
> Hang on, where are you? I've never even seen an airon unit that doesn't
> heat. There's always a "mode" button on the remote.

Plenty of whole house aircon units here that don't have a remote,
never mind not being capable of operating in heating mode.

> You must be somewhere really primitive, like the USA, maybe. :-)

Rumbled. Minnesota, to be precise. It was -20 °C this morning.

--
FJR1300A, GL1000, KLR650A6F, EX250J9A, DR200SE, Vespa Ciao

On Friday, January 27, 2023 at 7:10:49 PM UTC, siwilson wrote:
> I've been looking more closely at heat pumps again, to try and advise
> someone who's living in a house with only infra-red ceiling panels and a
> wood burning stove.
>

>
> Anyone got an air-air system, or know someone who's got one?
>

I installed a small Fujitsu high wall split AC system in our bedroom that is in a converted loft. I did it mainly to provide some cooling in summer which it does very well but of course it also heats as it's a heat pump. Although the house has gas central heating, we now only use the heat pump at night in winter and it seems to heat the bedroom pretty well even on cold nights. It's been in place for a couple of years now and hasn't given any trouble.

You do have to dig a bit to find the actual performance info at UK conditions rather than nominal conditions but it is available. Once you find that, it will give you an actual heating capacity at winter conditions taking into account defrost etc. However, I appreciate that I do this stuff for a living and can check the actual equipment performance against my estimate of the heat required and make a judgement on whether the unit is suitable. Whereas most will rely on a sales person who in truth knows little more than they do about it and that is where the problems begin.

As a bit of an academic exercise I put an electrical meter on it to see how it performs. It is nominally rated at about 2.5 kW of heating and cooling capacity. The highest I have seen it consume in a day are around 2.5 kWhrs back in December for about 8 hours usage. Obviously in heating mode. In cooling mode, it was 9.05 kWhrs in July (probably that 40°C day) and probably covering about 18 hours of usage as I use the bedroom as home office in summer. Total consumption for 2022 was 358 kWhrs.

For what it's worth I think split ac systems - be they individual systems, multi splits or even mini VRF - are a potential contender for heating UK homes. I consider the air to water heat pumps being offered in the UK at the moment as grossly over priced. Splits do have some drawbacks though. You would still need some way to heat your hot water as well as smaller rooms such as bathrooms that wouldn't justify their own indoor unit. There are also planning issues to be considered with the installation of any heat pump or AC equipment.

--
Big Tony

Big Tony <afsullivan@gmail.com> wrote in
news:f9e73903-e4ba-43fa-9eae-59c81dab8459n@googlegroups.com:

> On Friday, January 27, 2023 at 7:10:49 PM UTC, siwilson wrote:
>> I've been looking more closely at heat pumps again, to try and advise
>> someone who's living in a house with only infra-red ceiling panels
>> and a
>
>> wood burning stove.
>>
>
>>
>> Anyone got an air-air system, or know someone who's got one?
>>
>
>

[snip]

> You do have to dig a bit to find the actual performance info at UK
> conditions rather than nominal conditions but it is available. Once
> you find that, it will give you an actual heating capacity at winter
> conditions taking into account defrost etc. However, I appreciate that
> I do this stuff for a living and can check the actual equipment
> performance against my estimate of the heat required and make a
> judgement on whether the unit is suitable. Whereas most will rely on a
> sales person who in truth knows little more than they do about it and
> that is where the problems begin.
>

[snip]

and there we have it children, the meme continues, where UKRM will always
have an expert on any subject ...

On 07/02/2023 08:59, Big Tony wrote:

<snip useful info>

Thanks.

E-mailed.

--
/Simon

wessie <willnotwork@tesco.net> wrote:

> and there we have it children, the meme continues, where UKRM will always
> have an expert on any subject ...

Just out of casual interest, who is the resident expert on dwarf
albino porn these days?

--
FJR1300A, GL1000, KLR650A6F, EX250J9A, DR200SE, Vespa Ciao

On 2/7/2023 6:10 AM, Mark Olson wrote:
> wessie <willnotwork@tesco.net> wrote:
>
>> and there we have it children, the meme continues, where UKRM will always
>> have an expert on any subject ...
>
> Just out of casual interest, who is the resident expert on dwarf
> albino porn these days?
>
NOT me! I know nothing about it! I swear. Absolutely NOTHING!

--
The erstwhile Thomas
FJR1300, R1200GS & ST1100 (in memoriam)

Mark Olson <olsonm@tiny.invalid> wrote in
news:trtm5e$3ounu$2@dont-email.me:

> wessie <willnotwork@tesco.net> wrote:
>
>> and there we have it children, the meme continues, where UKRM will
>> always have an expert on any subject ...
>
> Just out of casual interest, who is the resident expert on dwarf
> albino porn these days?
>

I think it's more of a Research Group than a single person.

On 07/02/2023 14:10, Mark Olson wrote:
> wessie <willnotwork@tesco.net> wrote:
>
>> and there we have it children, the meme continues, where UKRM will always
>> have an expert on any subject ...
>
> Just out of casual interest, who is the resident expert on dwarf
> albino porn these days?
>

Aren't you on the mailing list?
The researxh is published weekly.

--
Remove the '+' and replace with 'plus' to reply by email

On Tuesday, 7 February 2023 at 19:33:26 UTC, wessie wrote:
> Mark Olson <ols...@tiny.invalid> wrote in
> news:trtm5e$3ounu$2...@dont-email.me:
> > wessie <willn...@tesco.net> wrote:
> >
> >> and there we have it children, the meme continues, where UKRM will
> >> always have an expert on any subject ...
> >
> > Just out of casual interest, who is the resident expert on dwarf
> > albino porn these days?
> >
> I think it's more of a Research Group than a single person.

Led by Strichy perhaps? he's been out for 4 years

On 07/02/2023 09:26, wessie wrote:
>
> and there we have it children, the meme continues, where UKRM will always
> have an expert on any subject ...

At least one expert, and at least one more opinion than the number of
experts.

On Wednesday, February 8, 2023 at 3:46:48 PM UTC, Mike Fleming wrote:
> On 07/02/2023 09:26, wessie wrote:
> >
> > and there we have it children, the meme continues, where UKRM will always
> > have an expert on any subject ...
> At least one expert, and at least one more opinion than the number of
> experts.

Don't forget that opinions can also sometimes differ between experts.

On 09/02/2023 18:41, Big Tony wrote:
> On Wednesday, February 8, 2023 at 3:46:48 PM UTC, Mike Fleming wrote:
>> On 07/02/2023 09:26, wessie wrote:
>>>
>>> and there we have it children, the meme continues, where UKRM will always
>>> have an expert on any subject ...
>> At least one expert, and at least one more opinion than the number of
>> experts.
>
> Don't forget that opinions can also sometimes differ between experts.

Catered for in the above sentence. Rather the point of the above
sentence, in fact.