Based on €œaverage€� gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was under the
impression that gas was cheaper for equivalent output.

Tim


--
Please don't feed the trolls

Tim+ wrote:

I keep hearing folk extolling the virtues of heat-pumps but I was under the
impression that gas was cheaper for equivalent output.

as ever "it varies", but poke some answers into

https://www.kensaheatpumps.com/heat-pump-costs/#cost-calc

The electricity costs for a heatpump will be about 85% of the cost for
mains gas,m but the installation costs are much higher.

On 01/10/2020 18:23, Andy Burns wrote:
Tim+ wrote:

I keep hearing folk extolling the virtues of heat-pumps but I was
under the
impression that gas was cheaper for equivalent output.

as ever "it varies", but poke some answers into

https://www.kensaheatpumps.com/heat-pump-costs/#cost-calc

The electricity costs for a heatpump will be about 85% of the cost for
mains gas,m but the installation costs are much higher.


You can now get £5k towards the cost of the heat pump.

GB wrote:

You can now get £5k towards the cost of the heat pump.

You're better off getting the RHI, which "ought" to pay the install
costs over a 7 year period plus or minus a grand, you can in fact have
the £5k payment too (to save on upfront costs) but if you have both,
they'll claw back the £5k.

On 01/10/2020 18:23, Andy Burns wrote:
Tim+ wrote:

I keep hearing folk extolling the virtues of heat-pumps but I was
under the
impression that gas was cheaper for equivalent output.

as ever "it varies", but poke some answers into

https://www.kensaheatpumps.com/heat-pump-costs/#cost-calc

The electricity costs for a heatpump will be about 85% of the cost for
mains gas,m but the installation costs are much higher.

Is that figure for ground sourced or air sourced heat pumps?

From my back of envelope previous investigations, an air sourced pump
can give 3kW thermal energy for every 1kW of electricity but as the
outside temperature falls to 0C this efficiency also drops to more like
2KW thermal per 1KW. As my electricity tariff is 4x that of my gas
tariff it is debatable that air sourced in the UK can be cost effective.
However all the green wash is not about saving money but saving the
planet and in 2050 when all the oil, gas, coal and wood is banned you
will have no choice.

Installing an EFFECTIVE heat pump system also depends on the level of
insulation in the home and probable there are large additional costs
involved in changing components (radiators) on a water based CH system
which may/will be running at lower water temperatures. Again the whole
ethos of saving the planet is not about saving money but using less energy.

It may work extremely well for a new build where you can specify the
quality of the build and insulation.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 01/10/2020 17:58, Tim+ wrote:

Based on €œaverage€� gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was under the
impression that gas was cheaper for equivalent output.

IIUC, the best CoP you will get out of a air sourced heat pump in winter
is about 3, but only if you can cope with a low output temp of around 40
deg. If you need 60, then it will fall to about 2.

So in theory (downhill, wind behind it etc) you might be able to get 4kW
(total) out for every 1kW in. Which in energy cost terms is probably
comparable to gas. However I expect real world will be somewhat less
convincing. Certainly worth doing if if your only choice is electric
heating though.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

alan_m wrote:

Andy Burns wrote:

The electricity costs for a heatpump will be about 85% of the cost for
mains gas, but the installation costs are much higher.

Is that figure for ground sourced or air sourced heat pumps?

ground source.

From my back of envelope previous investigations, an air sourced pump
can give 3kW thermal energy for every 1kW of electricity but as the
outside temperature falls to 0C this efficiency also drops to more like
2KW thermal per 1KW.

yes COP falls with temperature, but 1m below ground coils don't get as
cold as air, unless coils are undersized and you end up freezing the
ground by over-extracting.

Installing an EFFECTIVE heat pump system also depends on the level of
insulation in the home

as I said, poke some answers into the calculator.

It may work extremely well for a new build where you can specify the
quality of the build and insulation.

Can still be marginal ...

On 01/10/2020 19:40, alan_m wrote:
On 01/10/2020 18:23, Andy Burns wrote:

From my back of envelope previous investigations, an air sourced pump
can give 3kW thermal energy for every 1kW of electricity but as the
outside temperature falls to 0C this efficiency also drops to more like
2KW thermal per 1KW.




This is backed up by very good article by Prof at Cardiff University
....... air to air heatpumps great in a bar or club where loads of people
giving off heat ..... in a domestic environment not so good. His advice
was if you have a water source then water to air much better fro
efficiency or even ground source. He was also pretty scathing about
reliability/longevity of pumps ...

On 01/10/2020 18:23, Andy Burns wrote:
Tim+ wrote:

I keep hearing folk extolling the virtues of heat-pumps but I was
under the
impression that gas was cheaper for equivalent output.

as ever "it varies", but poke some answers into

https://www.kensaheatpumps.com/heat-pump-costs/#cost-calc

The electricity costs for a heatpump will be about 85% of the cost for
mains gas,m but the installation costs are much higher.

And the most effective refridgerant gases have been made 'illegal'
(AFAIK) and you need to also need to factor in possibly higher
maintenance costs compared to a gas heating system.

Paul in Canada had quite a lot to say about this recently (heat pumps).

On 01/10/2020 20:08, rick wrote:
He was also pretty scathing about reliability/longevity of pumpsÂ* ...

Something that people don't seem to be aware of (yet).

On 01/10/2020 19:45, John Rumm wrote:
On 01/10/2020 17:58, Tim+ wrote:

Based on €œaverage€� gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was
under the
impression that gas was cheaper for equivalent output.

IIUC, the best CoP you will get out of a air sourced heat pump in winter
is about 3, but only if you can cope with a low output temp of around 40
deg. If you need 60, then it will fall to about 2.

So in theory (downhill, wind behind it etc) you might be able to get 4kW
(total) out for every 1kW in. Which in energy cost terms is probably
comparable to gas. However I expect real world will be somewhat less
convincing. Certainly worth doing if if your only choice is electric
heating though.




Neighbour in a 4-bed detached 1974 built house had an air-to-water
Sanyo system installed. All the rads were replaced by triple-panel
variety (8 of them).

They also have the 4KW solar panels on the roof (37 degree pitch,
facing due south).

I asked 'er-indoors what it was like in winter, and she replied
'freezing'. So they have to burn logs etc on the fire (Class 1
chimney added by previous owner in the 1980's) to keep warm.

Andrew wrote:

you need to also need to factor in possibly higher
maintenance costs compared to a gas heating system.

manufacturers claim zero maintenance costs for 7 years.

On 01/10/2020 20:08, rick wrote:
On 01/10/2020 19:40, alan_m wrote:
On 01/10/2020 18:23, Andy Burns wrote:

Â*From my back of envelope previous investigations, an air sourced pump
can give 3kW thermal energy for every 1kW of electricity but as the
outside temperature falls to 0C this efficiency also drops to more
like 2KW thermal per 1KW.


This is backed up by very good article by Prof at Cardiff University
...... air to air heatpumps great in a bar or club where loads of people
giving off heat

Is this for cooling the building rather than heating during the winter?


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Thursday, 1 October 2020 19:53:00 UTC+1, Andy Burns wrote:


yes COP falls with temperature, but 1m below ground coils don't get as
cold as air, unless coils are undersized and you end up freezing the
ground by over-extracting.


Assuming it is under your lawn, you might save some lawnmower energy usage!

On 01/10/2020 19:52, Andy Burns wrote:
alan_m wrote:

Andy Burns wrote:

The electricity costs for a heatpump will be about 85% of the cost
for mains gas, but the installation costs are much higher.

Is that figure for ground sourced or air sourced heat pumps?

ground source.

From my back of envelope previous investigations, an air sourced pump
can give 3kW thermal energy for every 1kW of electricity but as the
outside temperature falls to 0C this efficiency also drops to more
like 2KW thermal per 1KW.

yes COP falls with temperature, but 1m below ground coils don't get as
cold as air, unless coils are undersized and you end up freezing the
ground by over-extracting.

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs. In
theory they should have been ideal customers being retired and at home
all day but they were sold a pup. It cost more than fuel oil to do the
same heating job (back when oil was still expensive pre-Covid).

Radiators all had to be replaced with big ugly things to cope with the
lower working temperature so it wasn't a cheap or simple installation.

Installing an EFFECTIVE heat pump system also depends on the level of
insulation in the home

as I said, poke some answers into the calculator.

It needs the home very well insulated or your are burning money.

It may work extremely well for a new build where you can specify the
quality of the build and insulation.

Can still be marginal ...

Air source can work except in the coldest weather but again unless the
house is very well insulated it quickly gets expensive to run. I know
someone with it who is quite happy - highly insulated new build.

--
Regards,
Martin Brown

Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet

In
theory they should have been ideal customers being retired and at home
all day but they were sold a pup. It cost more than fuel oil to do the
same heating job (back when oil was still expensive pre-Covid).

I'm still trying to weigh-up whether to go for GSHP or LPG on a new
build, it is quite touch and go.

Andrew Wrote in message:
On 01/10/2020 18:23, Andy Burns wrote:
Tim+ wrote:

I keep hearing folk extolling the virtues of heat-pumps but I was
under the
impression that gas was cheaper for equivalent output.

as ever "it varies", but poke some answers into

https://www.kensaheatpumps.com/heat-pump-costs/#cost-calc

The electricity costs for a heatpump will be about 85% of the cost for
mains gas,m but the installation costs are much higher.

And the most effective refridgerant gases have been made 'illegal'
(AFAIK) and you need to also need to factor in possibly higher
maintenance costs compared to a gas heating system.

Paul in Canada had quite a lot to say about this recently (heat pumps).


Not like Paul...:^)
--
Jimk


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Thu, 01 Oct 2020 21:17:22 +0100, Andy Burns wrote:

Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet


We've got a large number of houses with ground and air.
The air are not recommended, they are as expensive as using electric
storage heaters and an immersion heater.

In theory they should have been ideal customers being retired and at
home all day but they were sold a pup. It cost more than fuel oil to do
the same heating job (back when oil was still expensive pre-Covid).

I'm still trying to weigh-up whether to go for GSHP or LPG on a new
build, it is quite touch and go.

Ground, in theory, should be the way to go, if, you can get a good
installer. 4 deep holes seems to be the best way of fitting it now, some
of the ones we have only have one hole, and , of course, are nowhere near
as efficient as those with more and deeper holes.

On 01/10/2020 17:58, Tim+ wrote:
Based on €œaverage€� gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

in merely cool weather a heat pump can achieve a 4:1 uplift which puts
it at about 5p/KWh.

That's comparable in my case with oil at 50p/liter.


I keep hearing folk extolling the virtues of heat-pumps but I was under the
impression that gas was cheaper for equivalent output.

Well compare the figures above. I have no idea what gas costs.

And remember in the depths of winter even a 5KW heat pump at 2:1 uplift
may not be enough...


Tim




--
€œThe ultimate result of shielding men from the effects of folly is to
fill the world with fools.€�

Herbert Spencer

On 01/10/2020 21:17, Andy Burns wrote:
Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet

Possibly their problem too. Look very carefully at ongoing maintenance
costs too - that was their other major gripe.

In theory they should have been ideal customers being retired and at
home all day but they were sold a pup. It cost more than fuel oil to
do the same heating job (back when oil was still expensive pre-Covid).

I'm still trying to weigh-up whether to go for GSHP or LPG on a new
build, it is quite touch and go.

If you can design it in as underfloor central heating and get the
building insulation very very good then you might have a chance.

--
Regards,
Martin Brown

Andy Burns wrote:
Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet

About a decade ago the Energy Saving Trust did a research project examining
installs of heat pumps, then fairly new, and identifying issues. The
reports are worth a read:
https://energysavingtrust.org.uk/sit...0part%202a.pdf
https://energysavingtrust.org.uk/sit...web%281%29.pdf
http://oro.open.ac.uk/31521/1/Domest... 12%29%29.pdf
https://www.gov.uk/government/public...mp-field-trial

This was before the MCS installation standards, and the findings were
incorporated into them. They went back and modified some of the
installations and performance was much improved, although the sample sizes
were small.

That was a decade ago. The government has some newer reports:
https://www.gov.uk/government/collec...rch#heat-pumps
but there doesn't appear to be a followup study.

I imagine heat pumps have improved and the quality of installations
likewise. I would be interested to know of any more recent research (rather
than 'friend of a friend' anecdata).

Theo

On Fri, 2 Oct 2020 10:13:17 +0100, The Natural Philosopher wrote:

in merely cool weather a heat pump can achieve a 4:1 uplift which puts
it at about 5p/KWh.

That's comparable in my case with oil at 50p/liter.

Not bought oil or looked at prices recently? Around 30p/litre these
days. (32.37 + VAT on 18th March...) Pre Covid 'twas around 50p/l.

And remember in the depths of winter even a 5KW heat pump at 2:1 uplift
may not be enough...

10 kW certainly wouldn't be enough here. Retrofitting a heatpump
system to and old property and greatly upping radiator sizes to get
enough output from them at 40 to 50 C strikes me as fraught with
problems. It certainly won't respond quickly to a cold snap.
Underfloor at least stands a chnace with a big thermal mass and
surface area to store and release heat at hopefully a decent rate.

--
Cheers
Dave.

Tim+ wrote:
Based on €œaverage€� gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was under the
impression that gas was cheaper for equivalent output.

Tim



I am dubious I remember too many wonder solutions to save money / energy
which turned out to be scams. The principle is the same as a fridge but
with the cold bit being outside so you cool the outside and transfer the
energy/heat inside but anyone who keeps a freezer in an outbuilding should
know unless you get the right freezer it doesnt work well in winter as a
neighbour discovered. The same neighbour has a huge defunct solar water
heating system on his roof. It cost a fortune and never worked properly his
wife was always complaining about cold showers.

Martin Brown wrote:
On 01/10/2020 21:17, Andy Burns wrote:
Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet

Possibly their problem too. Look very carefully at ongoing maintenance
costs too - that was their other major gripe.

In theory they should have been ideal customers being retired and at
home all day but they were sold a pup. It cost more than fuel oil to
do the same heating job (back when oil was still expensive pre-Covid).

I'm still trying to weigh-up whether to go for GSHP or LPG on a new
build, it is quite touch and go.

If you can design it in as underfloor central heating and get the
building insulation very very good then you might have a chance.


Underfloor Heating is wonderful to live with but bloody expensive to run a
friend has it but dreads the bills. We visited when they first moved in and
it was glorious but next time we needed thermal underwear and were given
blankets in the sitting room after the first bill.

On Thursday, October 1, 2020 at 5:58:41 PM UTC+1, Tim+ wrote:
Based on €œaverage€� gas and electricity costs
Snip

I am getting lots of adverts on my FB feed at the moment (probably because I clicked on the first one) pushing Air Source as a way to save up to 80% of my Oil costs.

I presume the idea is to fit Air Source such that it provides some heat until to the conventional system until it runs out of steam and then the oil boiler fires up to "top up" / take it to the required temp to run the existing rads & cylinder.

but I've not investigated further, as that would doubtless need a visit from a "Surveyor" (Sales Reptile).

Radio Man wrote:
Underfloor Heating is wonderful to live with but bloody expensive to run a
friend has it but dreads the bills. We visited when they first moved in and
it was glorious but next time we needed thermal underwear and were given
blankets in the sitting room after the first bill.

UFH is just a big radiator. Like any radiator, it's up to you what you
connect it to.

Electric UFH is just a big electric resistance heater, and unsurprisingly
that costs to run. Wet UFH can be hooked up to a boiler or heat pump - the
latter can run more efficiently due to a lower flow temperature.

With any UFH, if somebody installs it with no insulation underneath you're
heating the ground not the floor. That's a faulty installation.

Assuming minimal losses to the ground, the heat flux from wet UFH should be the
same as radiators and so the efficiency roughly the same.

(although I don't know how the boiler copes with a mixed UFH/radiator system
- I assume the UFH isn't going to run at radiator temperatures? Is there a
thermostatic mixer?)

Theo

Chris Holmes wrote:
On Thursday, October 1, 2020 at 5:58:41 PM UTC+1, Tim+ wrote:
Based on €œaverage€� gas and electricity costs
Snip

I am getting lots of adverts on my FB feed at the moment (probably because
I clicked on the first one) pushing Air Source as a way to save up to 80%
of my Oil costs.

First rule of thumb: ignore all Facebook adverts

I presume the idea is to fit Air Source such that it provides some heat
until to the conventional system until it runs out of steam and then the
oil boiler fires up to "top up" / take it to the required temp to run the
existing rads & cylinder.

That's a hybrid heat pump:
https://assets.publishing.service.go...al_report-.pdf

I suspect the scammy adverts are claiming that replacing an ASHP will cost
20% of your oil costs. If there's any justification for that, it's probably
an outlier.

A HHP might make sense in some cases, but I suspect they fail to account for
the installation costs (even after grant).

but I've not investigated further, as that would doubtless need a visit
from a "Surveyor" (Sales Reptile).

There are plenty of legit firms out there to enquire of, although with the
GHG they're quite busy at the moment.

Theo

On 02/10/2020 10:57, Radio Man wrote:
Martin Brown wrote:
On 01/10/2020 21:17, Andy Burns wrote:
Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet

Possibly their problem too. Look very carefully at ongoing maintenance
costs too - that was their other major gripe.

In theory they should have been ideal customers being retired and at
home all day but they were sold a pup. It cost more than fuel oil to
do the same heating job (back when oil was still expensive pre-Covid).

I'm still trying to weigh-up whether to go for GSHP or LPG on a new
build, it is quite touch and go.

If you can design it in as underfloor central heating and get the
building insulation very very good then you might have a chance.


Underfloor Heating is wonderful to live with but bloody expensive to run a
friend has it but dreads the bills. We visited when they first moved in and
it was glorious but next time we needed thermal underwear and were given
blankets in the sitting room after the first bill.



nice to see he is cheap like me....tee hee

On 02/10/2020 10:56, Radio Man wrote:
Tim+ wrote:

Based on €œaverage€� gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was under the
impression that gas was cheaper for equivalent output.

I am dubious I remember too many wonder solutions to save money / energy
which turned out to be scams. The principle is the same as a fridge but
with the cold bit being outside so you cool the outside and transfer the
energy/heat inside but anyone who keeps a freezer in an outbuilding should
know unless you get the right freezer it doesnt work well in winter as a
neighbour discovered. The same neighbour has a huge defunct solar water
heating system on his roof. It cost a fortune and never worked properly his
wife was always complaining about cold showers.

There was a heat pump system advertised a couple of years ago that took
the heat from "exhaust gasses". All right if you live in a laundry or
restaurant kitchen, but most people keep their windows closed in the
winter, with minimal ventilation.

Needless to say it cost a fortune to run. Testimonials boasted "toasty
warmth" and "piping hot water" without mentioning cost.

--
Max Demian

Max Demian wrote:
There was a heat pump system advertised a couple of years ago that took
the heat from "exhaust gasses". All right if you live in a laundry or
restaurant kitchen, but most people keep their windows closed in the
winter, with minimal ventilation.

Those are designed for super-insulated new-build small flats/houses, where
you have heat generating sources (appliances, people, bathrooms) but need to
change the air. Ordinarily people would crack a window, but these new
builds are highly sealed and so they have active ventilation. The
warm/moist/smelly air goes out, fresh air comes in. In a normal MVHR system
you just have a heat exchanger to transfer heat from stale to fresh air.
In these exhaust air heat pumps (EAHPs) they heat exchange, but also
use a heat pump to pull more external air and raise the temperature of the
fresh air beyond that of the heat exchanger. Because the place is
well-insulated, it doesn't need a lot of heat input to keep equilibrium.

The problems are that the heat pump only works to a certain output. Beyond
that there's only electrical resistance heating, which costs a lot. Some
systems silenty fall back to resistance mode without it being obvious.

When can happen is if the place is too leaky (eg the householder opens
windows or the ventilation ducts aren't properly installed), or the heat
pump is undersized, it falls back to resistance mode and the bills are
high.

https://en.wikipedia.org/wiki/Exhaust_air_heat_pump

Theo

On 02/10/2020 10:39, Dave Liquorice wrote:
On Fri, 2 Oct 2020 10:13:17 +0100, The Natural Philosopher wrote:

in merely cool weather a heat pump can achieve a 4:1 uplift which puts
it at about 5p/KWh.

That's comparable in my case with oil at 50p/liter.

Not bought oil or looked at prices recently? Around 30p/litre these
days. (32.37 + VAT on 18th March...) Pre Covid 'twas around 50p/l.

And remember in the depths of winter even a 5KW heat pump at 2:1 uplift
may not be enough...

10 kW certainly wouldn't be enough here. Retrofitting a heatpump
system to and old property and greatly upping radiator sizes to get
enough output from them at 40 to 50 C strikes me as fraught with
problems. It certainly won't respond quickly to a cold snap.
Underfloor at least stands a chnace with a big thermal mass and
surface area to store and release heat at hopefully a decent rate.

Really heat pumps need massive insulation to reduce heat loss and
ginormous radiators or UFH or in wall pipework. That is almost
impossible to retrofit to an older house at a sane cost


--
"When a true genius appears in the world, you may know him by this sign,
that the dunces are all in confederacy against him."

Jonathan Swift.

On 02/10/2020 12:36, Max Demian wrote:
There was a heat pump system advertised a couple of years ago that took
the heat from "exhaust gasses". All right if you live in a laundry or
restaurant kitchen, but most people keep their windows closed in the
winter, with minimal ventilation.

Needless to say it cost a fortune to run. Testimonials boasted "toasty
warmth" and "piping hot water" without mentioning cost.

It is possible to use a heat recovery system to pre heat condenser air,
- you simply have a fixed exit for ventilated air and heat up what is
going in with the heat pump



--
"The most difficult subjects can be explained to the most slow witted
man if he has not formed any idea of them already; but the simplest
thing cannot be made clear to the most intelligent man if he is firmly
persuaded that he knows already, without a shadow of doubt, what is laid
before him."

- Leo Tolstoy

On 02/10/2020 10:57, Radio Man wrote:
Martin Brown wrote:
On 01/10/2020 21:17, Andy Burns wrote:
Martin Brown wrote:

The only person I have met that had one installed in domestic premises
was bitterly disappointed with the running and servicing costs.

I've heard one second-hand tale where the coils were undersized and it
couldn't extract sufficient heat, still not sorted yet

Possibly their problem too. Look very carefully at ongoing maintenance
costs too - that was their other major gripe.

In theory they should have been ideal customers being retired and at
home all day but they were sold a pup. It cost more than fuel oil to
do the same heating job (back when oil was still expensive pre-Covid).

I'm still trying to weigh-up whether to go for GSHP or LPG on a new
build, it is quite touch and go.

If you can design it in as underfloor central heating and get the
building insulation very very good then you might have a chance.


Underfloor Heating is wonderful to live

Quite likely in some cases...

with but bloody expensive to run a

As an unqualified statement that is not even wrong.

There is no reason why it should be any more expensive that other forms
of heating necessarily. However it does need to be properly installed
with appropriate levels of insulation under the heating matrix.

With a condensing gas boiler, it will let you run at high condensing
efficacy pretty much all of the time. It can also be a good way of using
lower grade energy sources like solar thermal.

If you use electric UFH with no heat pump (i.e. just resistive heating)
then it will be expensive, as is any form of resistive electric heating
(and unlike storage heating, you can't shift as much to cheap rate prices).

Also consider the choice of floor coverings. If you favour heavy carpet
on thermal underlay, then UFH is not a good match. Solid tiled, wood etc
floors however work well.

Its works best in places that are continuously heated, since there are
usually longer hear up times.

friend has it but dreads the bills. We visited when they first moved in and
it was glorious but next time we needed thermal underwear and were given
blankets in the sitting room after the first bill.

So extrapolating from an example of one, all UFH systems are to be
condemned huh?



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John.

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On 02/10/2020 11:42, Theo wrote:
snip
(although I don't know how the boiler copes with a mixed UFH/radiator system
- I assume the UFH isn't going to run at radiator temperatures? Is there a
thermostatic mixer?)

There is a thermal mixer on the UFH manifolds but having marginally
up-sized radiators in the bedrooms (downstairs/under ground) it's
enabled me to run upstairs living area (6 UFH zones)and downstairs
radiators all at a max. temp of 55 degrees when it's 9 degrees outside
with a reducing boiler temp as outside temp rises.

Might be a different story in "normal" house though.

I'd have thought any heat pump would be wasted if you could not use it to
cool the place in the summer. They seem to be on top of this stuff in New
Zealand.
Brian

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"Tim+" wrote in message
...
Based on "average" gas and electricity costs (and ignoring for the moment
other changes that might need to be made to a heating system for an air
sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was under
the
impression that gas was cheaper for equivalent output.

Tim


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Pamela wrote:
On 10:56 2 Oct 2020, Radio Man said:
Tim+ wrote:

Based on average gas and electricity costs (and ignoring for the
moment other changes that might need to be made to a heating system for
an air sourced heat-pump) which would be cheaper per kWhr?

I keep hearing folk extolling the virtues of heat-pumps but I was under
the impression that gas was cheaper for equivalent output.

Tim



I am dubious I remember too many wonder solutions to save money / energy
which turned out to be scams. The principle is the same as a fridge but
with the cold bit being outside so you cool the outside and transfer the
energy/heat inside

Did you get taken in by that one?


If the explanation was too difficult for you to understand then google how
they work or stick to cleaning up after hairdressers.

On 02/10/2020 15:43, John Rumm wrote:


Its works best in places that are continuously heated, since there are
usually longer hear up times.

You end up with a warm bum if you sit on it for any length of time. As
any undergraduate who has visited friends in St Catherine's Oxford will
attest.

Martin Brown wrote:

If you can design it in as underfloor central heating and get the
building insulation very very good then you might have a chance.

They are both Plan A

On Friday, October 2, 2020 at 7:17:36 PM UTC+1, Andy Burns wrote:
Martin Brown wrote:

If you can design it in as underfloor central heating and get the
building insulation very very good then you might have a chance.
They are both Plan A
I have a friend, newish build. His second hand air source pump failled. He was going to buy a new one, £10k, with a life expectancy of 10 years.

On 02/10/2020 11:42, Theo wrote:
Electric UFH is just a big electric resistance heater, and unsurprisingly
that costs to run. Wet UFH can be hooked up to a boiler or heat pump - the
latter can run more efficiently due to a lower flow temperature.

We've got it installed in our (downstairs) bathroom. It's not the main
heat - it's got a towel-rail-come-radiator - and it's only on for an
hour or two in the morning.

Which means we have warm feet getting out of the shower

I don't think I'd want to do the whole house like that though.

Andy