Air Source Heat Pumps
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My other dilemma is on size of the solar system based on current usage I've been recommended a 4 kw system but if I go down the aircon / heat pump solution I assume I'd be better served by a bigger system perhaps 5kw.....does anyone recommend solar batteries my concern is that with the investment in battery technology cheaper better batteries are likely just round the corner.
For reference my house floor area is about 1700 sq ft
Sorry for the long post
Hiya, you could do both.
Keep the LPG system, get PV installed, then install a small ASHP, perhaps 3.5kW (that's what I've done) for about £1k.
When you don't need a lot of heating, just use the ASHP for the room or two rooms that you use the most, and if there's too much heat you can use doors as a simple way to spread excess around the property.
During the warmer colder months (Mch/Apr & Sept/Oct/Nov) you may not want the full GCH on, but still have enough PV generation to cover all or most of the ASHP during the day. Or after a morning
burn of the GCH to warm the house, you use the ASHP to keep the chill off the room or two you use, before an evening GCH burn.
Obviously, you'd want to go for the biggest PV system you can fit on the property, since the cost goes down (proportionately) as you go bigger, since the panels are relatively cheap now. So if you can fit 5kWp or 6kWp (or even more), worth considering, especially in this scenario.
You may even find yourself using summer excess to charge an EV in the future.
Batts will help with a PV system, but for the UK, best to wait for a few years at least, as the market is still young, and expensive, and costs are still falling. A retro fit plug-n-play system will be fine later on if required/economical.Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)
For general PV advice please see the PV FAQ thread on the Green & Ethical Board.0 -
Hello all,
I'm an avid reader of forums but this is my first time posting. My partner and I have recently moved into a very old solid wall granite house. It's not on the gas mains and had old storage heaters which we instantly ripped out! We had thought of installing under floor heating but this would have been expensive to retrofit. So we opted for a big wood burner. Last winter this was sufficient for space heating and we were surprised at the insulating properties of the thick walls and as its open plan it heated the living room- kitchen and dining space. We have small electric heaters in the 3 bedrooms and bathroom. We're in the south of Scotland with minus temps for a few weeks each year. My partner works from home so economy 7 electric tariffs aren't beneficial for us.
Getting to the point- I recently bought a second hand Worcester bosch air source heat pump for only £100. I liked the idea of being eco friendly and having an outdoor boiler room to free up space in the house. The air source unit is 9.5kw. Primarily I want it to heat all of our domestic hot water- bath, two showers and washing the dishes etc. As a secondary, if it runs well and is working we could plumb in some over sized radiators to the bedrooms and bathroom. It has a 200l tank with it. We'll have to plumb in pipes from the boiler room to the house (about 4 meters).
Some people have taken one look and said that with a unit that size it'll be less expensive to just have an immersion heater for hot water. What do you all think? Any advice much appreciated!0 -
Getting to the point- I recently bought a second hand Worcester bosch air source heat pump for only £100.
Welcome to the forum.
Why was it being sold?
From your post it is an Air to Water heat pump. Without pouring cold water! on your project, it is difficult enough to get such a system installed when purpose designed.0 -
It dpends how much hot water you get through.
We've got a 200l tank connected to our 11kw Daikin ASHP. at this time of the year. It's on for two hours a day and it uses around 1.8-2kwh to heat our tank to 45 degrees. That gives us all the hot water we need for a couple of showers, hand washing & washing up - we can get four showers because we dont stand in there for ages - around 4 minutes each and we've got an eco shower head.
The unit heats the whole of our 135m2 bungalow in the winter using an overlay u/f heating system. As said, you need to keep the flow temperature low, which means oversized rads and running it for longer periods than a conventional heating system but if you got it cheap and the plumbing is realatively easy then I'd certainly go for it.Never under estimate the power of stupid people in large numbers0 -
That would be great, I am in Somerset and getting very conflicting prices, quotes, sizing of units, and makes! Mitsubishi Eco Dan 11.2KW vs Daikin 16Kw LT Split! Any suggestions. Thanks Bazzer0
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Hello all,
I'm an avid reader of forums but this is my first time posting. My partner and I have recently moved into a very old solid wall granite house. It's not on the gas mains and had old storage heaters which we instantly ripped out! We had thought of installing under floor heating but this would have been expensive to retrofit. So we opted for a big wood burner. Last winter this was sufficient for space heating and we were surprised at the insulating properties of the thick walls and as its open plan it heated the living room- kitchen and dining space. We have small electric heaters in the 3 bedrooms and bathroom. We're in the south of Scotland with minus temps for a few weeks each year. My partner works from home so economy 7 electric tariffs aren't beneficial for us.
Getting to the point- I recently bought a second hand Worcester bosch air source heat pump for only £100. I liked the idea of being eco friendly and having an outdoor boiler room to free up space in the house. The air source unit is 9.5kw. Primarily I want it to heat all of our domestic hot water- bath, two showers and washing the dishes etc. As a secondary, if it runs well and is working we could plumb in some over sized radiators to the bedrooms and bathroom. It has a 200l tank with it. We'll have to plumb in pipes from the boiler room to the house (about 4 meters).
Some people have taken one look and said that with a unit that size it'll be less expensive to just have an immersion heater for hot water. What do you all think? Any advice much appreciated!
If you are just looking at DHW at the moment. then possibly try the Ariston Nuos heat pump, as that could fit your needs.As Manuel says in Fawlty Towers: " I Know Nothing"0 -
Hi everyone. Im a newby but i have a question (or 2)......
Recently built a new house in Scotland Aberdeenshire. Installed a 16kw Grant air source heat pump.
I have noticed that the unit is using a vast amount of electricity. Up to 90 units per day!! Thats everything mind you - household appliances etc....
My question is, what settings does everyone use for the hot water and central heating with the heat pump?? I was using mine on a timed program. Central heating coming on for 2 hours in morning & 2 hours evening. Hot water 1 hour in morning and 1 hour at night ( also boosted by the 3kw immersion daily for 1 hr). Should i have the central heating set to ‘ON’ constant?? We have digital room stats that would maintain the temperature. My thinking now is that the heat pump is having to draw considerable power in order to get the rooms up to the temperature set on the stats (21 degrees)
If i leave it on constant - it will draw far less power as it will be just ‘ticking over’ to maintain a steady temperature.
Any help appreciated folks.
Also - should the hot water be set to ‘ON’ as well or left on timed?
Thanks all
0 -
Hi everyone. Im a newby but i have a question (or 2)......
Recently built a new house in Scotland Aberdeenshire. Installed a 16kw Grant air source heat pump.
I have noticed that the unit is using a vast amount of electricity. Up to 90 units per day!! Thats everything mind you - household appliances etc....
My question is, what settings does everyone use for the hot water and central heating with the heat pump?? I was using mine on a timed program. Central heating coming on for 2 hours in morning & 2 hours evening. Hot water 1 hour in morning and 1 hour at night ( also boosted by the 3kw immersion daily for 1 hr). Should i have the central heating set to ‘ON’ constant?? We have digital room stats that would maintain the temperature. My thinking now is that the heat pump is having to draw considerable power in order to get the rooms up to the temperature set on the stats (21 degrees)
If i leave it on constant - it will draw far less power as it will be just ‘ticking over’ to maintain a steady temperature.
Any help appreciated folks.
Also - should the hot water be set to ‘ON’ as well or left on timed?
Thanks all
You leave it on constant with set back temps. Your thinking is right. To have it work extra hard to get it upto 21c it will struggle. Also your flow temp should be as low as possible to heat the house. Night set back should be say 18/19c no lower. Then comfort temp of 21c. If you turn it off fully it has to work extra hard to get house back upto temp also the house will feel colder even when is it at that temp as the fabric still has to warm up. Also when you installed it did you oversize radiators for the lower flow temps?
What’s your flow temp at? Having the hot water on timed is not a problem really as the tank will be so well insulated it will lose hardly any heat.If you found my post helpful, please remember to press the THANKS button! --->0 -
As Richard says you cannot use a heat pump like a boiler. They should run for a lot longer but at much lower flow temperatures.
Most boilers run at around 70 degrees whereas a heat pump should ideally be no more than 40, less if possible. That means they take a long time to get the house up to temperature. Instead of turning it on and off as with a conventional boiler you reduce the temperature by around 3 degrees. It takes a bit of trial and error to get it right.
Likewise the hot water, we keep ours at 45 degrees with a boost once a week to 60 degrees to protect against legionella. We've got a 200l tank which heats for about two hours every morning before we get up and there's plenty for us to both shower and for all our hot water needs throughout the day and a bit left over for the next day. It uses laround 2kwh of leccy.
Most heatpumps wont go much above 50-55 degrees so by having the water hotter than than causes the backup or immersion heater to kick in which has a COP of one.
Looking at the Grant ASHP info it has a COP (Coefficient of Performance) juts over 4 when the outside temp is 7 degrees and the flow temp is 35 degrees. however this drops to around 2.6 when the flow temperature is 55 degrees. Costing 60% more to run it.
You need to learn how it works and to tweak it to optimise it's performanceNever under estimate the power of stupid people in large numbers0 -
matelodave wrote: »As Richard says you cannot use a heat pump like a boiler. They should run for a lot longer but at much lower flow temperatures.
Most boilers run at around 70 degrees whereas a heat pump should ideally be no more than 40, less if possible. That means they take a long time to get the house up to temperature. Instead of turning it on and off as with a conventional boiler you reduce the temperature by around 3 degrees. It takes a bit of trial and error to get it right.
Likewise the hot water, we keep ours at 45 degrees with a boost once a week to 60 degrees to protect against legionella. We've got a 200l tank which heats for about two hours every morning before we get up and there's plenty for us to both shower and for all our hot water needs throughout the day and a bit left over for the next day. It uses laround 2kwh of leccy.
Most heatpumps wont go much above 50-55 degrees so by having the water hotter than than causes the backup or immersion heater to kick in which has a COP of one.
Looking at the Grant ASHP info it has a COP (Coefficient of Performance) juts over 4 when the outside temp is 7 degrees and the flow temp is 35 degrees. however this drops to around 2.6 when the flow temperature is 55 degrees. Costing 60% more to run it.
You need to learn how it works and to tweak it to optimise it's performance
What times do you set your comfort times from and your set back temps from?
eg if your set back temp is 18c what is the recovery time back to 21c?If you found my post helpful, please remember to press the THANKS button! --->0
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