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Air to Air : Air Source Heating

Making your money go further
BusyBumbleBee
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Re: Air to Air : Air Source Heating

#245412

Postby BusyBumbleBee » August 19th, 2019, 10:46 am

gryffron wrote:
dspp wrote:ASHP designed to deliver 'full' heating in such circumstances become pure electrical heaters, i.e. the heat pump part of the kit becomes useless. So for (say) 364 days of the year they get the benefit of a CoP that is (say) 3:1, and for (say) one day of the year they operate with a CoP of 1:1.

Do they actually have a heater element? Oh, are you saying some systems do?
But it is sub 5degC many cold winter mornings. Even today with global warming et al. So it is certainly not going to be operating at full efficiency for 364 days of the year. Or even close. And the times when you need most heating it is least efficient.

Gryff - definitely sticking with gas, for now.

I totally agree with you sticking to gas now - and for the foreseeable future. Air source heating is not for everyone but in the right circumstances (and there are a lot of those) it is very sensible to install it. Where there is no gas (as in darkest rural Norfolk for example) and where night storage heaters are used are two examples. I have saved enormous amounts of electricity and oil by installing these - and have been warmer because they circulate the air so your feet are warm.

CO2 reduction is not about one size fits all or one solution - it is really about finding a plethora of different things in different circumstances that will make a difference to what carbon dioxide you produce. And the enemy of this aim is waiting to find the best or perfect solution.

with kind regards - ~ BBB

PS look at this link which shows you can get equipment that will work well at lower temperatures but that will cost more money to install : look for the heading "in cold climates"

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Re: Air to Air : Air Source Heating

#245585

Postby BusyBumbleBee » August 19th, 2019, 8:50 pm

WHOOPS - here's the link I missed off the last post https://en.wikipedia.org/wiki/Air_sourc ... d_climates

Gan020
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Re: Air to Air : Air Source Heating

#245675

Postby Gan020 » August 20th, 2019, 9:59 am

I've had a ASHP for 10 years or so with no other heating and I feel a number of posters on this thread misunderstand how you use them.

What you do not do is turn them on in the same way as a convential boiler. Instead you run them for longer hours and they "maintain" the temperature you want. So, whilst it is true that their efficiency drops as the temperature drops, you are only maintaining the temperature inside the house.

If the temperature is at say +2 during the day and then falls to -5 during the evening and overnight you will be fine, because the house will be at the required temperature when the evening arrives, the heat pump will have plenty of capacity and will not cost too much as it won't go through the defrost cycle too often.

When the tempearture is -2 during the day and then -5 overnight you will still be fine as the heat pump should have been sized to deal with this. It will be chewing up energy compared with usual.

I will agree if the temperature is at -5 during they day and than -10 overnight it is going to struggle. Certainly mine does not cope then. But how often does that happen and how well would your boiler cope? When it really gets this bad for days on end we turn off the heating in a couple of rooms if we can.

The point about heat pumps not working below a certain temperature is irrelevant in the UK. Mine operates down to -25C

I pay about £1500 for electricity for a very large four bedroom house. That's all my enery costs. I have no gas. I do have PC solar panels and also solar thermal panels for hot water (in the summer). In fact if you ignore the purchase costs of the solar panels I make money as the feed in tariff income easily exceeds my electricity costs as I was an early adopter

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Re: Air to Air : Air Source Heating

#245779

Postby BusyBumbleBee » August 20th, 2019, 3:47 pm

Well said, Gan020

I have just bought a book "Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming" put together by Paul Hawken. Amazon say this about it
NEW YORK TIMES BESTSELLER

For the first time ever, an international coalition of leading researchers, scientists and policymakers has come together to offer a set of realistic and bold solutions to climate change. All of the techniques described here - some well-known, some you may have never heard of - are economically viable, and communities throughout the world are already enacting them. From revolutionizing how we produce and consume food to educating girls in lower-income countries, these are all solutions which, if deployed collectively on a global scale over the next thirty years, could not just slow the earth's warming, but reach drawdown: the point when greenhouse gasses in the atmosphere peak and begin to decline. So what are we waiting for?
which is actually a pretty fair description.

On page 95 it says that :
Heating and cooling of residential and commercial building space requires more than 13,000 terawatt-hours of energy and is estimated to increase to more than 18,000 terawatt-hours by 2050... current adoption is low at 0.02% of the market
and
While cost can be high and efficiency fluctuates depending on local climate, heat pumps are easy to adopt, well understood, and already in use around the world. They can supply indoor heating, cooling, and hot water—all from one integrated unit. When it comes to efficiency, heat pumps have a singular advantage: For every unit of electricity consumed, an equivalent of up to five units of heat energy is transferred. According to the International Energy Agency, a 30 percent penetration of the building sector by appropriate heat pumps could reduce worldwide carbon dioxide emissions by 6 percent. This would be one of the larger contributions of any technology now on the market.

If that is only half right it could make an amazing difference.

For my sins, I work closely with town and parish councils and am chairman of a "Task and Finish" group working to encourage all councils in my county to take the climate change issue seriously to which end we have undertaken to organise about 170 mini conferences/workshops/meetings/seminars over the next four years (actually it is only 24 but each one is repeated 7 times in different areas of the county). The first batch will concentrate on 'electricity' and heat pumps will feature heavily.

Any ideas on the next 23 and what are the most important topics?

Itsallaguess
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Re: Air to Air : Air Source Heating

#245808

Postby Itsallaguess » August 20th, 2019, 5:43 pm

BusyBumbleBee wrote:
For my sins, I work closely with town and parish councils and am chairman of a "Task and Finish" group working to encourage all councils in my county to take the climate change issue seriously to which end we have undertaken to organise about 170 mini conferences/workshops/meetings/seminars over the next four years (actually it is only 24 but each one is repeated 7 times in different areas of the county).

The first batch will concentrate on 'electricity' and heat pumps will feature heavily.

Any ideas on the next 23 and what are the most important topics?


How about -

"Skype technology, and it's crucial place in minimising polluting travel to conferences, workshops, meetings and seminars"?

:O)

Cheers,

Itsallaguess

ReformedCharacter
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Re: Air to Air : Air Source Heating

#245822

Postby ReformedCharacter » August 20th, 2019, 6:19 pm

Itsallaguess wrote:
How about -

"Skype technology, and it's crucial place in minimising polluting travel to conferences, workshops, meetings and seminars"?

:O)

Cheers,

Itsallaguess

Yes, absolutely. AFAIK all the schools (and many council office buildings) in my local council area were provided with teleconferencing facilities, upgraded Internet etc. Do they get used? NO. When you take into account the time wasted by people travelling to meetings, often at xp\mile, the extra traffic, the parking problems, the pollution and so forth, you might think it was a 'no-brainer' but that isn't the case, somewhat to my annoyance.

RC

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Re: Air to Air : Air Source Heating

#246126

Postby NomoneyNohoney » August 21st, 2019, 8:23 pm

Why don't thy get used?

UncleEbenezer
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Re: Air to Air : Air Source Heating

#246179

Postby UncleEbenezer » August 22nd, 2019, 7:37 am

NomoneyNohoney wrote:Why don't thy get used?

Perhaps take a look at https://www.theregister.co.uk/2007/01/0 ... _business/ , and the followup article referenced in comments.

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Re: Air to Air : Air Source Heating

#246659

Postby jaizan » August 23rd, 2019, 11:08 pm

fisher wrote:
gryffron wrote:For this heat pump some COP examples are:
Cop of 4.65 to produce 35 degrees water when 7 degrees outside
Cop of 2.84 to produce 45 degrees water when 2 degrees outside
Cop of 2.42 to produce 45 degrees water when -7 degrees outside
Cop of 1.99 to produce 55 degrees water when -7 degrees outside
Cop of 1.89 to produce 45 degrees water when -15 degrees outside


Bear in mind that when electricity costs approximately 4 times the price of gas, a COP of ~3.6 is needed for this to be competitive with mains gas (assuming 90% boiler efficiency).
In a location with no mains gas, then air source or ground source heating would be attractive.

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Re: Air to Air : Air Source Heating

#246662

Postby gryffron » August 23rd, 2019, 11:36 pm

NomoneyNohoney wrote:Why don't they get used?

Have you actually tried it? Teleconferencing is nothing like the same as being in the same room with other people. It just doesn't work. I don't know why. But it doesn't. It results in a totally different style of conversation. Lack of social connection or something. Maybe the lack of tiny social cues we all use. Maybe even the millisecond delays prevent the conversation from flowing properly. But you just can't "connect" to or read a computer image like you can a real living person.

I can't explain why. But teleconferencing is still nothing like a face to face meeting. Obviously lots of people agree with me. Which is why people keep flying all around the world to meetings.

:cry:

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Re: Air to Air : Air Source Heating

#246706

Postby fisher » August 24th, 2019, 10:07 am

jaizan wrote:Bear in mind that when electricity costs approximately 4 times the price of gas, a COP of ~3.6 is needed for this to be competitive with mains gas (assuming 90% boiler efficiency).
In a location with no mains gas, then air source or ground source heating would be attractive.


I am on an Economy 7 tariff so the night time electricity rate is much less than 4 times the cost of gas. My ASHP runs through the night maintaining the temperature. This helps the cost efficiency. I also have solar panels. My electricity bill for a large 5 bedroom house for all heating, cooking, lighting etc is less than £1200 per annum.

I do not have access to gas and if I did I would probably have a gas boiler. Certainly while gas is so relatively cheap but how long will that last? Heat pumps are still a viable option though if you insulate well and set them up properly.

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Re: Air to Air : Air Source Heating

#246738

Postby BusyBumbleBee » August 24th, 2019, 12:06 pm

jaizan wrote:
fisher wrote:
gryffron wrote:For this heat pump some COP examples are:
Cop of 4.65 to produce 35 degrees water when 7 degrees outside
Cop of 2.84 to produce 45 degrees water when 2 degrees outside
Cop of 2.42 to produce 45 degrees water when -7 degrees outside
Cop of 1.99 to produce 55 degrees water when -7 degrees outside
Cop of 1.89 to produce 45 degrees water when -15 degrees outside
Bear in mind that when electricity costs approximately 4 times the price of gas, a COP of ~3.6 is needed for this to be competitive with mains gas (assuming 90% boiler efficiency).
In a location with no mains gas, then air source or ground source heating would be attractive.

To add to this :

1. An air source heat pump's output does not decline with increasing winds.
2. The average winter temperature is 7 degrees so a lot of the time the heat pump is running at a COP greater than 4.65
3. The fabric of the house tends to be warmer with air source heating cos it runs for longer so you can reduce the air temperature in the house
4. with air to air - circulates the air in the house so your feet are as warm as your head so you feel warmer and so can run at a lower thermostat setting.

In a location with no mains gas, then air source or ground source heating is attractive

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Re: Air to Air : Air Source Heating

#246799

Postby JohnB » August 24th, 2019, 6:11 pm

Is it noisy? My only experience with blown air systems in Colorado, where they use it for heating and a/c was it was quite distracting

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Re: Air to Air : Air Source Heating

#246805

Postby fisher » August 24th, 2019, 6:46 pm

JohnB wrote:Is it noisy? My only experience with blown air systems in Colorado, where they use it for heating and a/c was it was quite distracting


Mine isn't overly noisy. Mine is outside our Utility room and is not next to any living areas, although it is near our Music Room and underneath the window to the guest bedroom. I think during winter when cold outside it can be noisy doing its defrost. The fans can also make some noise when the machine is working flat out. Both of these occasions coincide with windows being tightly closed in our house so we don't notice it. No guests have ever been bothered by it.

Mine is not attached to the house directly, it is on its own stand a few inches from our outside wall. I wouldn't like it next to a living room of any sort. I think that would be risking too much noise or vibration.

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Re: Air to Air : Air Source Heating

#246914

Postby BusyBumbleBee » August 25th, 2019, 4:53 pm

JohnB wrote:Is it noisy?
Not a simple question to answer - particularly as there are two kinds

a) air to water . One external unit : often a clunk as it switches on or off and can develop an annoying rattle, Properly positioned it should not produce noise you can hear inside - and it won't very often be working when you are outside as the weather is usually warmer when you do use the garden.

b) air to air (very often just air conditioning units). Two parts one internal and the other external. Both parts have variable speeds fans and there is usually no clunk/ click on/off. Both do make noise though but it is not intrusive. However, my younger daughter complains but then, when I put a pea under her mattress she complained about the lump she had to sleep on ;)

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Re: Air to Air : Air Source Heating

#404525

Postby jaizan » April 15th, 2021, 3:11 pm

BusyBumbleBee wrote:2. The average winter temperature is 7 degrees so a lot of the time the heat pump is running at a COP greater than 4.65

If you look as average COP per day, that result might not be too bad.
If you look at average COP v kWh of output required, it will be much worse. The heating requirement is much much higher when we have very cold temperatures.

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Re: Air to Air : Air Source Heating

#426491

Postby Spritehawk » July 10th, 2021, 4:54 pm

I had an air source heat pump installed last year and here are my thoughts.

We didn't have gas to the house, so a gas boiler wasn't an option and we were previously heating with oil-filled radiators. The biggest shock for me was that our heating costs didn't seem to reduce with the ASHP. Granted, the radiators were on timer and parts of the house were cold, especially at night, but I thought the ASHP would be cheaper. As previously mentioned, though, it is 'on' all the time and just ticks over to keep the house warm. It is on all night, so it is pleasant if you need to get up in the wee small hours (excuse the pun!). We are within a mile of the sea, so I had the coastal option on the pump which is more corrosion-resistant.

The noise is similar to the bathroom fan in my experience. Although if the outside temperature drops the ASHP works harder and is slightly noisier - this is when the temp drops to around 5 - 8 degrees C.

We did get a grant from the RHI which will cover most of the purchase and installation cost BUT - the grant depends on your starting point (taken from an EPC report) and the installer must be approved/registered. And - you only find out what you will get AFTER the installation. And - the grant drips in over seven years - not much good unless you have the cash up front!

But all in all, I am pleased with it. It's nice to have the house at a constant temperature and I can kid myself I'm doing my bit for the planet. To be honest, if we'd had a gas supply I would probably have gone with the easy option of getting a gas central heating system, but I'm happy with what we've got. Just don't expect a big drop in your electricity bill!

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Re: Air to Air : Air Source Heating

#426552

Postby AJC5001 » July 10th, 2021, 9:51 pm

Spritehawk wrote:I had an air source heat pump installed last year and here are my thoughts.

We didn't have gas to the house, so a gas boiler wasn't an option and we were previously heating with oil-filled radiators. The biggest shock for me was that our heating costs didn't seem to reduce with the ASHP. Granted, the radiators were on timer and parts of the house were cold, especially at night, but I thought the ASHP would be cheaper. As previously mentioned, though, it is 'on' all the time and just ticks over to keep the house warm. It is on all night, so it is pleasant if you need to get up in the wee small hours (excuse the pun!). We are within a mile of the sea, so I had the coastal option on the pump which is more corrosion-resistant.

The noise is similar to the bathroom fan in my experience. Although if the outside temperature drops the ASHP works harder and is slightly noisier - this is when the temp drops to around 5 - 8 degrees C.

We did get a grant from the RHI which will cover most of the purchase and installation cost BUT - the grant depends on your starting point (taken from an EPC report) and the installer must be approved/registered. And - you only find out what you will get AFTER the installation. And - the grant drips in over seven years - not much good unless you have the cash up front!

But all in all, I am pleased with it. It's nice to have the house at a constant temperature and I can kid myself I'm doing my bit for the planet. To be honest, if we'd had a gas supply I would probably have gone with the easy option of getting a gas central heating system, but I'm happy with what we've got. Just don't expect a big drop in your electricity bill!


A couple of questions if I may?

1. Does the ASHP supply radiators or underfloor pipes or something else?

2. Does the ASHP provide Domestic Hot Water as well as heating or is this by immersion heater?

Adrian

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Re: Air to Air : Air Source Heating

#426560

Postby doug2500 » July 10th, 2021, 10:44 pm

Reply to above, in my case it's underfloor and it does hot water too.

In my case the whole house was designed for it which is when they work at their best, given the low temp they work at it's not ideal to swap out a hotter boiler with no other mods.

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Re: Air to Air : Air Source Heating

#426844

Postby Spritehawk » July 11th, 2021, 9:47 pm

In my case we had to install radiators, so the ASHP acts like a conventional gas central heating system, although the radiators tend to be bigger and don't get as hot - it's a gentle, maintenance of heat rather than a hot blast to warm a room from scratch.

The ASHP also provides the hot water, although there is an emergency backup immersion element. This also comes into play when the system heats up to over 60 degrees C once a week as a legionella prevention. The immersion heater kicks in then to bring the water up to temperature quickly.


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