Heat Pumps - post here.

antoinolachtnai

i would be concerned about the pricing here. At the end of the day this is a more complex unit that is more expensive to manufacture and commission compared to a heat pump.

The heat requirement of a new build should be quite low and you should be able to get a heat pump to cover it. And it should be cheaper than this unit.

This unit makes sense in a situation where the heat requirement can be met by the heat pump most of the year, but an oil boost is only required a few days a year on the coldest days.

You also have to take account of the cost of an oil tank and the issues around deliveries. And the extra maintenance requirements.

zoom_cool

KCross wrote: »

But it will be a more complex system and you have to have an oil tank and oil burner and it will need more servicing and you have to order oil etc etc.... I just dont see why you would do that over having a single heat pump system in a new build house. I just dont see the advantage (smart controls or not) outweighing the disadvantages unless the price differential was significant.

Note, you can tweak heat pump settings to take advantage of night rate electricity as well. You cant run it entirely at night but you can limit it and in a new build, with low heat demand, I dont think oil should be considered at all, imo.

For a retrofit it might make sense.


For a new build you should be lookng to get as much of your consumption onto electricity as you can with an eye to SolarPV. Putting in oil in a 2019 house is questionable,again imo.

Thanks KCross what are the best heat pumps out there is it Danfoss, Daikin, Nibe etc.

mjsc1970

Hi.
I've moved in to an A rated new build with A2W Dimplex Heat Pump set up. Am trying to get to grips with it and what's the most effecient way to use it.

I've the HotWater timed for twice a day and this sorts all our households needs for the day. Maybe it's on for too long as I don't seem to ever run out of warm water.

But, as regards house/space heating I've not quite got to grips with. Without the heating on, house is comfortable at 20.5C. When it drops below this I tend to manually put the boiler on to heat the rads up to 22C. My question is, is it more effeciant to leave the boiler ON constantly, so as, when internal temperature drops below a certain limit, the space heating kicks on and automatically brings the heating temperature up to a comfortable level in which case it would kick in automatically when target temperature drops and off when target temperature is reached. Is this the best way to operate?

KCross

zoom_cool wrote: »

Thanks KCross what are the best heat pumps out there is it Danfoss, Daikin, Nibe etc.

The service guys on the forum will need to answer that. I dont know. I have a Nibe myself (but Geothermal, not A2W) and it has been low maintenance for the last 7yrs (one €200 component died and no other costs other than the electricity, of course).

Shefwedfan

H.E. Pennypacker wrote: »

I've had a few quotes for A2W retrofit. Most companies who have experience with this are happy to talk about a potential multi-step approach where the customer can try the HP with existing radiators. One suggested running the existing OFCH at 40C supply to see how it goes. Its not ideal if you'd like to maximise the lifespan of your existing boiler but as a stepping stone its a very useful insight.

The biggest issue that I've found is that the companies most willing to deal aren't yet SEAI approved for grant purposes. It requires FETAC Level 6 plumbers and a lot of companies are aircon, not plumbing companies. That said, the SEAI requirements are very relevant for a retrofit scenario in terms of the fabric first approach and in my experience, they tend to maintain standards with contractors. You would need to have confidence in the heat loss attributes of your house and without a heat loss indicator of max 2.2 for retrofit you can't say for sure that it'll pay.

Thanks, I am talking to a company who mentioned a 16kW NIBE 2040 A2W heat pump.



Keep the oil boiler as a back up. They have connection box



THey have a installer who is certified and also can do the SEAI grant. This would potentially make sense as the current radiators etc they say will work with the system because they are new and all the piping has high insulation.



I seen a few companies around offering similar solution but this seems like good option. Just wondering if anyone is actually doing?



You mention running the boiler at 40 degree, does the A2W not run at 60 degree?

Shefwedfan

zoom_cool wrote: »

Does anybody have Firebird offering of AWH pump sister is building new house and got a quotation and they where very competitive. The system is called Enviroair Hybrid Heatpump which has a oil burner as a backup.

If doing a new build then a hybrid system is a waste of time. I would go full heat pump. Oil prices will only go one way....


I have a house built so as a retrofit this is what I would look at.....

KCross

Shefwedfan wrote: »

You mention running the boiler at 40 degree, does the A2W not run at 60 degree?

Heat pumps are designed to run at ~30C at the distribution point (underfloor, rads etc)
If you run it at 60C you will significantly shorten its lifespan.

This design is exactly why they are not recommended for traditional rads. They are designed for underfloor heating where 30C around the entire house floor area is good enough to heat the house but 30C in a stainless steel rad under a window will feel cold to the touch and wont radiate enough heat to make a difference.

Thread carefully if considering using a heat pump with stainless steel rads.

Shefwedfan

KCross wrote: »

Heat pumps are designed to run at ~30C at the distribution point (underfloor, rads etc)
If you run it at 60C you will significantly shorten its lifespan.

This design is exactly why they are not recommended for traditional rads. They are designed for underfloor heating where 30C around the entire house floor area is good enough to heat the house but 30C in a stainless steel rad under a window will feel cold to the touch and wont radiate enough heat to make a difference.

Thread carefully if considering using a heat pump with stainless steel rads.

Sorry with all the numbers from the guy I got mixed up. Yes it can run at 58 degree but that is the max. As you say the standard is around 30 degree constant.

I have checked my current boiler and it says on spec sheet: Boiler Thermostat Range: 65 to 80 degree. So I guess the minimum I can set this to is 65 degree.

It is not just the heat pump, this is the solution
https://www.nibe.eu/Products/AirWater-heat-pumps/NIBE-F2040/NIBE-F2040--VVM-310/

zoom_cool

Just so there is some info here is the details of the Hybrid setup Firebird offer

https://www.firebird.ie/images/pdf/Enviroair_Oil_Brochure.pdf

Latro

Just a quick update on my all stainless steel rads + heat pump retrofit set up.
For the whole month of October total electricity consumed 282kWh,
total heat generated 1236kWh, average COP for the month 4.4.
Total cost 39 euro.

https://imgur.com/a/EwGZcSy

The heat pump is never switched off. The house temp fluctuates between 20.8 to 21.7.

I still learn the system and tweak it occasionally to squeeze the most out of it. At the moment the weather compensating curve is set at -5 to +15 outdoor which translates to +40 to +30 water flow.

So far I had only 6-7 defrost cycles. Each of them took about 6 mins.
They came up when air temperature dropped under 2 degrees.

Last week was proper cold here. Temperature went down to -3 few times.
On these days average COP was at about 3.3

When the temps are above 7-8 degrees outside the heat pump sits constantly at 0.4 kW power consumption. I guess it is the lowest modulation it can achieve.

https://imgur.com/a/Tep6qdt

Shefwedfan

Latro wrote: »

Just a quick update on my all stainless steel rads + heat pump retrofit set up.
For the whole month of October total electricity consumed 282kWh,
total heat generated 1236kWh, average COP for the month 4.4.

Scrub that....found

Latro

https://www.boards.ie/vbulletin/showthread.php?t=2055433218&page=82
Bottom of the page, post 1230

KCross

Shefwedfan wrote: »

Sorry with all the numbers from the guy I got mixed up. Yes it can run at 58 degree but that is the max. As you say the standard is around 30 degree constant.

I have checked my current boiler and it says on spec sheet: Boiler Thermostat Range: 65 to 80 degree. So I guess the minimum I can set this to is 65 degree.

It is not just the heat pump, this is the solution
https://www.nibe.eu/Products/AirWater-heat-pumps/NIBE-F2040/NIBE-F2040--VVM-310/

Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

Draughty houses dont work well with HP's.

Latro's system works, primarily I assume, because its insulated to within an inch of its life and so 30C at the stainless steel rad is all the house needs.

How much oil are you burning is the thing and would the money you are considering spending on an A2W be better spent on insulation, airtighness and heat-recovery first?

Latro

KCross wrote: »

Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

It doesn't necessarily mean that. It depends how long he had those 65C on per day to achieve satisfactory temperature.


If you run those 65C for lets say 4-5 hours per day there is good chance that running water at 30-40 degrees like myself for 24h will achieve same or better result.
The comfort would definitely be better as there would be little to no fluctuations in temperature throughout the day.


If his house is drafty it will be cold and expensive to heat regardless of heating source.

KCross

Latro wrote: »

It doesn't necessarily mean that. It depends how long he had those 65C on per day to achieve satisfactory temperature.

Exactly, which is why I said: "... and you are using a significant amount of oil..."

H.E. Pennypacker

KCross wrote: »

Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

Draughty houses dont work well with HP's.

Latro's system works, primarily I assume, because its insulated to within an inch of its life and so 30C at the stainless steel rad is all the house needs.

How much oil are you burning is the thing and would the money you are considering spending on an A2W be better spent on insulation, airtighness and heat-recovery first?

I fully agree and the SEAI are taking the same approach. Grant conditions are quite strict and its unlikely that an unsuitable house will qualify. The only flaw that I can see is that a door blower test is not mandatory. Money should definitely be spent on every possible fabric upgrade before a heat pump is considered. At that stage, it'd be cheap to run an oil boiler so there's more thought needed then.

Personally, I don't see the point in a hybrid system. If you need one, you need oil so why not keep it simple and stick with an oil burner.

Will the SEAI give the grant for a hybrid system? The aim of the grant is to move people away from fossil fuel burning and a hybrid system doesn't achieve that.

FWIW, my boiler is heating the house quite easily at 40C I assume that its running for longer to do that but its not noticeable and the cycle time seems normal. I don't plan on tearing up floors so I'm planning A2W with rads. I need more certainty around actual heat demand but I'm assuming a COP of 2.5 and the figures work for me at that.

Shefwedfan

KCross wrote: »

Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

Draughty houses dont work well with HP's.

Latro's system works, primarily I assume, because its insulated to within an inch of its life and so 30C at the stainless steel rad is all the house needs.

How much oil are you burning is the thing and would the money you are considering spending on an A2W be better spent on insulation, airtighness and heat-recovery first?

I think worse case i do 2-2.5 fills per year

I do like a bit of insulation myself.....60% of the house has walls pumped plus then insulated slabs on the walls and ceiling, then ceiling topped up with fiber glass.....I done air tightness on windows etc, put in draft lobby with triple glaze...oh yeah dug up floors and put down 120mm I think of insulation.....

The other section has just pumped walls and insulation in attic...windows I think the guy said got done in 2006-2009 so newish...was build circa 2009 so “should” have better insulation in floors etc that part had before I done up

Could maybe top up more in attic but would expect to do that before installation...

Not a cold house just not a small house......

KCross

Considering the amount of insulation you’ve detailed it seems like a lot of oil to still be burning through, notwithstanding it’s a large house.

An airtighness test or thermal imaging camera might be worth looking into?

John.G

KCross wrote: »

Considering the amount of insulation you’ve detailed it seems like a lot of oil to still be burning through, notwithstanding it’s a large house.

An airtighness test or thermal imaging camera might be worth looking into?

Seems a lot but the heat pump will monitor pretty exactly what the house/hot water heat demand is and will be very interesting and also the weather compensation curve required in very cold weather.
I have a 145 M2 semi detached house cavity BLOCK! with attic conversion, attic roof very well insulated. No zoning apart from hot water cylinder, TRVs on all rads bar 2 which are on a room thermostat. I run the heating for 15hours/day, SE 20Kw Firebird Heatpac boiler and my average oil consumption for the past 6 years has been 1550 Litrs/year, say 1.5 "fills".

KCross

John.G wrote: »

Seems a lot but the heat pump will monitor pretty exactly what the house/hot water heat demand is and will be very interesting and also the weather compensation curve required in very cold weather.

I guess what I'm saying is that he seems to have done alot of remedial work to reduce the heat demand but still using alot of oil. I'd try to get the heat demand down further first, by running an airtightness test etc to see where the heat is going to, before forking out €10k for a HP system.

If he could, for instance, spend €4k on more remedial work and get the oil bill down to one fill it would then be much harder to justify spending the €10k on a HP system as you'd buy alot of oil for that.

Spending the €10k on the HP and monitoring its usage isnt going to change the heat demand of the house. Its just going to drive his electricity bill up and now he is maintaining two heating sources.

Latro

Shefwedfan burns about 2500L of oil. His house is 285sqm.


2500L*10kWh*0.8 / 285sqm = 70.1kWh/sqm/year


Add some electricity usage and that's about B2 in BER rating. Not bad for pre 2008 regs house. It will be very difficult to squeeze more out of it on relatively low cost.

John.G

KCross wrote: »

I guess what I'm saying is that he seems to have done alot of remedial work to reduce the heat demand but still using alot of oil. I'd try to get the heat demand down further first, by running an airtightness test etc to see where the heat is going to, before forking out €10k for a HP system.

If he could, for instance, spend €4k on more remedial work and get the oil bill down to one fill it would then be much harder to justify spending the €10k on a HP system as you'd buy alot of oil for that.

Spending the €10k on the HP and monitoring its usage isnt going to change the heat demand of the house. Its just going to drive his electricity bill up and now he is maintaining two heating sources.

You are quite correct.
I got mixed up between Latro & Shefwedfan, its Shefwedfan that uses a lot of oil.
If he cannot improve on the insulation and he wants a good COP by running at 40C then he will have to install very large rads because assuming a rad delta T of 5C and a required room temperature of 21C will give ((40+35)/2)-21, a "16.5C" rad which will only emit ~ 24% of the heat output of the same rad running as a "50C" rad, (16.5/50)^1.3.
I suppose thats why retrofitting using existing (or new) rads vs UFH is a big challenge in a house that requires a lot of heat and where you want to get a good COP.

Latro

John.G wrote: »

...a "16.5C" rad which will only emit ~ 24% of the heat output of the same rad running as a "50C" rad...

Or he would need to run them about 4 times longer.

285 sqm is a lot of space to heat. I'm not sure if 12kW HP would be enough. Probably it would but it is a little bit risky move and at 16kW you step into very expensive territory as there are no single phase HPs of that size.

Shefwedfan

KCross wrote: »

Considering the amount of insulation you’ve detailed it seems like a lot of oil to still be burning through, notwithstanding it’s a large house.

An airtighness test or thermal imaging camera might be worth looking into?

it's not really 2.5 fills. I have upped by half a fill. If I take last winter I would have filled in September(same this year) and then a fill probably in Feb/March. I don't think this was a full 1000 ltr as I had to swap the tank. Which I done during the summer.



My September fill is still maybe 80%+ full now so I would expect to be ok till Feb.....


My main issue is my wife....if she had her way the heating would be going 24 x 7 :P A2W would be perfect for her

banie01

The A2W heat pump is likely where I see my next home efficiency upgrade being.

I have a 1980's 3 bed semi and have pumped the walls with bonded bead, topped up the attic and installed triple Glazing.
Have Nest installed and heating rarely runs for more than 1hr a day.
I'm reading with interest the posts on radiators as I can't afford installing ufh and would like to keep as much of my existing equipment as possible and the rads are fairly new.

I'm leaning towards solar hot water, larger hot water tank and A2W. Is there an option to utilise the solar gain for heating? Or is it more efficient to stick with PV and use the electricity to run A2W?

Latro

Also he could consider installation of 2 fan coil radiators like those 6kW Irish made Solo range. 1 downstairs (ideally somwhere in open plan) and 1 upstairs (perhaps in landing area). They would greatly improve overall low temperature performance and they would allow for summer cooling. That would set him back extra 700-800 euro.

Latro

banie01 wrote: »

The A2W heat pump is likely where I see my next home efficiency upgrade being.

I have a 1980's 3 bed semi and have pumped the walls with bonded bead, topped up the attic and installed triple Glazing.
Have Nest installed and heating rarely runs for more than 1hr a day.
I'm reading with interest the posts on radiators as I can't afford installing ufh and would like to keep as much of my existing equipment as possible and the rads are fairly new.

I'm leaning towards solar hot water, larger hot water tank and A2W. Is there an option to utilise the solar gain for heating? Or is it more efficient to stick with PV and use the electricity to run A2W?

If you really only run oil 1h per day and you happy with the comfort I don't see why you would change to anything else at all. That 1h of oil boiler how much oil consumption does it transfer to?


If you switch to A2W PV is no brainer imo but would you really need them if your heat pump running cost was at E1.50 per day in the winter and maybe 0.20-0.30 in the summer?

banie01

Latro wrote: »

If you really only run oil 1h per day and you happy with the comfort I don't see why you would change to anything else at all. That 1h of oil boiler how much oil consumption does it transfer to?


If you switch to A2W PV is no brainer imo but would you really need them if your heat pump running cost was at E1.50 per day in the winter and maybe 0.20-0.30 in the summer?

It's gas fired but yeah I take your point. My gas is level pay but I'm currently still in credit on that my gas usage is quite low.
My downstairs is open plan"ish" and a small stove usually takes care of my downstairs heating and even that is run infrequently.

Your advice is much appreciated.
It's a change I can push out for a while longer then.

banie01

Latro wrote: »

If you really only run oil 1h per day and you happy with the comfort I don't see why you would change to anything else at all. That 1h of oil boiler how much oil consumption does it transfer to?


If you switch to A2W PV is no brainer imo but would you really need them if your heat pump running cost was at E1.50 per day in the winter and maybe 0.20-0.30 in the summer?

It's gas fired but yeah I take your point. My gas is level pay but I'm currently still in credit on that my gas usage is quite low.
My downstairs is open plan"ish" and a small stove usually takes care of my downstairs heating and even that is run infrequently.

Your advice is much appreciated.
It's a change I can push out for a while longer then.

John.G

Latro wrote: »

Or he would need to run them about 4 times longer.

285 sqm is a lot of space to heat. I'm not sure if 12kW HP would be enough. Probably it would but it is a little bit risky move and at 16kW you step into very expensive territory as there are no single phase HPs of that size.

A bit of zoning would help.

He would get some idea if he just monitors (listens) to his oil boiler ON cycle times over say a half or one hour period, if the boiler output is known then it is quite easy to calculate the house requirement. For example I know my boiler gives 20 Kw output. Once the house is up to temperature and obviously depending on ambient temperature it cycles ON for anything between 25% to 40% of time which means my requirements are between 5Kw and 8Kw. I know this is a bit rough and ready but it will certainly give some idea if 12 Kw is sufficient and of course a 12 KW unit will only give 5 or 6 Kw in very cold weather.