UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?
Comments
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So, my installation consisted of:
8.5KW Ecodan
New 200L water tank (at my request) - up from 140L
4 new rads; 2 in lounge, 1 in kitchen, 1 in main bedrooom
Plus, 1 rad moved from lounge to bedroom 2
New thermostatic valves on all rads
decommissioning of old boiler & make good
Total cost: £7,500 (net of grants - £850 from DECC and £400 from Mitsubishi)
I was paying £125 per month to Calor for LPG - just for heating, hot water was done by immersion heater. My installer estimates annual running costs for heating and hot water to be £550 (based on the heat loss estimate), so if that's true, a big annual saving on the £1500+ I was paying before. Only time will tell. On that basis, payback of around 7 years at current prices, albeit the RHI payments next year should make that much more attractive, hopefully payback in less than 5 years.
My lounge has a vaulted ceiling which takes longer to heat - the 1º per hour may vary by property type, but it is evident the rads don't get as hot - max temp would be 50º versus 70-80º (I would guess) for gas.
If the heating is on all day, the impact is relevant only to total resources consumed, i.e. if it's still cheaper to have ASHP on all day versus timed oil/gas, I guess that's a good outcome. ASHP have lower CO2 output, plus (and I like this spin off) it takes heat from the air, so in its own way it fights global warming
Early days, but I'm pleased to be free from LPG, especially since I offset the electric with solar PV and will do more as and when new opportunities (Ridgeblade?) come along.
:beer:0 -
Diallingtone wrote: »....., plus (and I like this spin off) it takes heat from the air, so in its own way it fights global warming .....
:rotfl: .... Apart from the issue that the heat that has been pumped inside leaks back out through the walls, windows, roof etc .... :eek:
... funny, but I've heard that particular argument used before, it's a bit like saying that leaving the freezer door open in the summer cools the kitchen ....
Z"We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
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Diallingtone wrote: »
My lounge has a vaulted ceiling which takes longer to heat - the 1º per hour may vary by property type, but it is evident the rads don't get as hot - max temp would be 50º versus 70-80º (I would guess) for gas.
If the heating is on all day, the impact is relevant only to total resources consumed, i.e. if it's still cheaper to have ASHP on all day versus timed oil/gas, I guess that's a good outcome. ASHP have lower CO2 output, plus (and I like this spin off) it takes heat from the air, so in its own way it fights global warming
Early days, but I'm pleased to be free from LPG, especially since I offset the electric with solar PV and will do more as and when new opportunities (Ridgeblade?) come along.
:beer:
Thank you.
The maximum CH water temperature for most gas boilers is 82C I believe.
Whilst the maximum temp of CH water(not HW) from your ASHP is 50C, surely you wouldn't normally run it at that temperature?0 -
:rotfl: .... Apart from the issue that the heat that has been pumped inside leaks back out through the walls, windows, roof etc .... :eek:
... funny, but I've heard that particular argument used before, it's a bit like saying that leaving the freezer door open in the summer cools the kitchen ....
Z
Sort of.
But the heatpump gives say 100kwh of heat inside for about 35kWh of electricity, whereas a gas boiler gives 100kWh of heat inside by burning about 110kWh of gas.
Yes, the heat sucked from the outside leaks back outside along with an extra dollop amounting to about 1/3rd, but with alternative heating, an extra whole dollop is leaked to the outside.
Or put yet another way, the atmosphere is heated by 110kwh for each 100kwh of home heating by gas, whereas for a heat pump, the atmosphere is only heated by 35kwh.
(Not that I think that matters).0 -
Diallingtone wrote: »
The defrost cycle is amazing. Last night, I was looking at the unit and it's all frozen up - looks like the inside of a fridge. Then the unit makes a noise a bit like a lorry's air-brakes and, after a few moments, the ice turns clear and starts to run off as water into the soakaway.
I:
Good to hear owner's views on these.
Yours seems very cheap compared to my quotes (about £12k/£13k for a 14kW, including new wet system). Wouldn't mind a quote from your installers, if you would care to divulge (either on the board or by pm).
Shame you didn't have any meters fitted. Although the defrost obviously works fine, I'd also like to know the cost of a defrost, and how often it occured at various temperatures. Not sure if Mitsi offer such metering, or whether it's available from third parties (or whether to make do with an inaccurate Owl).
Very useful info regarding noise etc, thanks.0 -
Must admit Im amazed at how good my Ecodan is at heating HW (i was bracing myself for the wife moaning about washing the dishes cold) - It is miles better than the oil range cooker/boiler it replaced.
The water temp gets up to 60 degc in a 210 litre tank in the same time it took the oil range to heat a 120l tank.
Personally I think heat pumps would work for any property (within reason), just the installer has to plan the extra rads and insulation for you. With fossil fuel boilers bad installers could cover their tracks by oversizing.
Got mine (8.5kw Ecodan + 210litre vented thermal store plus one new 1800mm wide rad) installed for £7200 inc vat and I havent had my RHPP yet. Its not that far off what a new external oil boiler would have cost me (inc cost of a new tank)
When you buy a new heating system of any sort you need to assume that most installers have no clue in what they are doing..In my limited experience about 60% are charlatans.Thank you.
The maximum CH water temperature for most gas boilers is 82C I believe.
Whilst the maximum temp of CH water(not HW) from your ASHP is 50C, surely you wouldn't normally run it at that temperature?0 -
Thank you.
The maximum CH water temperature for most gas boilers is 82C I believe.
Whilst the maximum temp of CH water(not HW) from your ASHP is 50C, surely you wouldn't normally run it at that temperature?
We have systems working on the 50C rad output temperature and the clients say that the temperature in the room is more stable and comfortable, as constant against when they had gas.As Manuel says in Fawlty Towers: " I Know Nothing"0 -
grahamc2003 wrote: »Sort of.
But the heatpump gives say 100kwh of heat inside for about 35kWh of electricity, whereas a gas boiler gives 100kWh of heat inside by burning about 110kWh of gas.
Yes, the heat sucked from the outside leaks back outside along with an extra dollop amounting to about 1/3rd, but with alternative heating, an extra whole dollop is leaked to the outside.
Or put yet another way, the atmosphere is heated by 110kwh for each 100kwh of home heating by gas, whereas for a heat pump, the atmosphere is only heated by 35kwh.
(Not that I think that matters).
Ah, but what about the CO2 footprint of the power station that generates that 35kWh?0 -
We have systems working on the 50C rad output temperature and the clients say that the temperature in the room is more stable and comfortable, as constant against when they had gas.
I can't see why that would be the case when they could have their gas boiler water temperature set to 50%
My point was that running an ASHP to give a water temperature of 50C gives a lower COP than, say, 35C.This is why heat pumps are so suited to under floor heating.
It is also a fact that some(not all by any means) people who have paid good money for a product, are less inclined to be objective in their appraisal of that product.. Even on MSE tenants(both council/HOA and private) generally are more critical of heat pumps.
I speak as someone who bought 2 Betamax VCRs and a Toshiba HD DVD player - convinced that VHS and Blu-ray wouldn't catch on!0 -
Hi Grahamgrahamc2003 wrote: »Sort of.
But the heatpump gives say 100kwh of heat inside for about 35kWh of electricity, whereas a gas boiler gives 100kWh of heat inside by burning about 110kWh of gas.
Yes, the heat sucked from the outside leaks back outside along with an extra dollop amounting to about 1/3rd, but with alternative heating, an extra whole dollop is leaked to the outside.
Or put yet another way, the atmosphere is heated by 110kwh for each 100kwh of home heating by gas, whereas for a heat pump, the atmosphere is only heated by 35kwh.
(Not that I think that matters).
I understand all of that, but the post was in reply to the premise that the heatpump was combating global warming by reducing the outside air temperature .... ie - "it takes heat from the air" ....
.... I had a conversation with an installer at a 'show' some time ago who used the same argument ... when the logic was countered with the freezer door in the summer scenario both representatives on the trade stand maintained that the freezer would actually cool the kitchen because it was pumping cold air out ..... having explained something to the effect that 1+3+-3 = +1 I simply walked away, leaving the one who finally understood (owner ?) discussing this with his colleague (salesman ?) .... :wall: .... it was some time ago, but does illustrate that many clueless installers take on new technologies just because of the relative high values & margins.
HTH
Z"We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle0
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