Heat Pumps - post here.

Condenser

sheff the ref wrote: »

I am in the same boat myself but I will have 200mm cavity pumped

Cannot decide what is best and it isn't a thing you can do trial an error with.

I will have to ultimately price the following and that is the best advice I can give

1.Underfloor with a Ground source heatpump (probably borehole rather than horizontal collector)

2.Underfloor with an Air Source heatpump

3.Oil and Radiators

The electricity running costs will be lower with a Ground Source heatpump but does it justify the extra cost?

You can't just focus on running cost even though a GSHP should be significantly better. Its also lifetime costs. Most ASHP's being sold now won't last longer than 12yrs, less if on the coast. A good GSHP could last 30yrs. That's a huge factor people ignore when choosing one over the other. Maintenance costs will also be less as there's far fewer moving parts.
A GSHP has a Compressor, expansion valve and circulating pump.
An ASHP has a Compressor, 2 expansion valves, fan motor, reversing valve and usually an inverter due to the need to deal with variances in temperature and a requirement to defrost so far more parts and processes to cause problems.

sheff the ref

A 6KW heatpump sounds very small for a house of that size.

Is there an alternative source of heat.

Big Dec wrote: »

Hi,

I have a GSHP with vertical collector (3 x 50m bores) for a 6kW heat pump.
I moved in at the end of October & am very happy with the system.
I'm still tweaking things, so don't really have a good idea of costs yet.
During the winter months it was ~€200 per month, but I was running the system hotter than required.
I'm hoping that this will be reduced for the next heating season as the house will have dried out a bit more & I'm told first heating season is always more expensive.
I have UFH downstairs & upstairs but not really sure if it is required for upstairs bedrooms.
It is definitely good for the bathrooms, so if pouring a screed anyway, I don't think there would be that much of a difference to add all rooms upstairs.

Sometimes cost should not be the only factor.
You also need to think about comfort - the UFH does give a nice even heat throughout.
I know that oil price is very low at the moment, and that works in favour of oil & radiators.
My heat pump and bore hole probably cost more that a conventional heating system with oil & radiators, but I am more than happy with it.
Over the life of the system, it may not save me that much money but I was happy to make that choice when installing.

House details:
- 3000 sq feet
- 150mm cavity wall pumped with Walltite foam
- 72mm insulated plasterboard on external walls

Big Dec

There is no alternative heat source.
I have the option to add a stove at a later date, but nothing yet.

An heating engineer ran the numbers for the heat demand and came up with the 6kW unit.
I should specify that the system combines heat pump, 180l cylinder & heat recovery all in one unit (Nilan Compact P GEO6).
The air tightness numbers are under 2 m3/hr/m2 so house is fairly airtight.
I have no trouble keeping it warm, in fact cooling it is my major concern. :-)

sheff the ref

I guess taking the air tightness into account and a built in hot water, plus the greater efficiency of modern systems would help.

I recall 10 years ago that similar sized houses would have been getting 15kw heatpumps and more

Big Dec

That is the idea all right.
Should have a u-value of 0.125 for walls & roof and 0.14 for floor.
The windows are triple glazed alu-clad with an average u-value of <0.8.

Bigger is not always better in terms of heat pump size (and same goes for oil boilers).
I have read horror stories about incorrectly installed systems costing €€€€€€s to run each month.
There are many threads here and on other forums on how to correctly size a heating system.

sheff the ref

A lot of those problems were due to the collector being too small meaning the fluid wasnt able to replenish itself to ambient temperature before returning to the heatpump. It wasnt because the heatpump was oversized.

Condenser

sheff the ref wrote: »

A lot of those problems were due to the collector being too small meaning the fluid wasnt able to replenish itself to ambient temperature before returning to the heatpump. It wasnt because the heatpump was oversized.

There's many reasons why heat pumps fail, rarely due to poor collectors. More likely to fail due to bad distribution systems or control systems and strategies or both. Always attributable to poor installer knowledge. Oversizing isn't a huge issue bar adding significant cost to the installation.


Ideally you should have the house modelled with all the info on u-values of windows, walls, roof etc. inputted along with proposed air tightness levels. An allowance can be made for thermal bridging if you're not going to passive detail. This should be simulated alongside weather data for the area. Only then will you know the correct heat loss for your house and what size heating system it needs. All other methods are finger in the wind stuff.

sheff the ref

From my experience of working in the field at that time, many of the houses that had problems were due to collectors being grossly undersized which in turn meant that a supplier could go in at a cheaper price. By slightly oversizing a heatpump, and having a collector that was more than sufficient, the running costs were under control.

In fairness that is going back 10-12 years ago when I worked at it. Air tightness wasn't spoken of so therefore any comparable heating systems that were highly successful and cheap to operate, had that success based on houses that weren't airtight. Control was based generally on time settings with stats calling for heat within the timed setting.

I guess things are different now, weather dependent controllers etc. The concrete plinth with the underfloor heating wasnt insulated then like it is now. Wall insulation was basic etc. Windows weren't taped.

Really and truly even without full air tightness, it shouldn't cost as much to heat a house in 2016 as it did in 2006.

Condenser wrote: »

There's many reasons why heat pumps fail, rarely due to poor collectors. More likely to fail due to bad distribution systems or control systems and strategies or both. Always attributable to poor installer knowledge. Oversizing isn't a huge issue bar adding significant cost to the installation.


Ideally you should have the house modelled with all the info on u-values of windows, walls, roof etc. inputted along with proposed air tightness levels. An allowance can be made for thermal bridging if you're not going to passive detail. This should be simulated alongside weather data for the area. Only then will you know the correct heat loss for your house and what size heating system it needs. All other methods are finger in the wind stuff.

Condenser

sheff the ref wrote: »

From my experience of working in the field at that time, many of the houses that had problems were due to collectors being grossly undersized which in turn meant that a supplier could go in at a cheaper price. By slightly oversizing a heatpump, and having a collector that was more than sufficient, the running costs were under control.

In fairness that is going back 10-12 years ago when I worked at it. Air tightness wasn't spoken of so therefore any comparable heating systems that were highly successful and cheap to operate, had that success based on houses that weren't airtight. Control was based generally on time settings with stats calling for heat within the timed setting.

I guess things are different now, weather dependent controllers etc. The concrete plinth with the underfloor heating wasnt insulated then like it is now. Wall insulation was basic etc. Windows weren't taped.

Really and truly even without full air tightness, it shouldn't cost as much to heat a house in 2016 as it did in 2006.

I mentioned on a thread here not 2 weeks ago the air tightness was not the end all and be all and there are plenty of houses we fitted units in 12yrs ago operating very successfully and for low running costs considering the heat losses involved.


Controls may have been like that on the units you were working on but we've been using weather compensation for 14yrs. There was far more wrong with poor installations back then than collectors. A certain Irish manufacturer for example had one mechanical stat in the heat pump which produced water to whatever level that stat was set for regardless of whether it was running underfloor heating or hot water. It was a disastrous system and I've replaced more of them than I'd care to count with very different results for the customer after the new system was installed.

sheff the ref

I personally believe I will have to bite the bullet and go with a ground source heat pump with a borehole setup even though I have plenty room for a horizontal collector. The excavation costs are too messy and for a house of 1900 square feet, I am not going to be putting in a massive heatpump anyway

I will also have a stove in the house and to be honest, it also makes sense to have solar. I may not have all the sources in place from day one, but I will definitely have the provisions and plumbing etc. in place for them which makes sense.

Condenser wrote: »

I mentioned on a thread here not 2 weeks ago the air tightness was not the end all and be all and there are plenty of houses we fitted units in 12yrs ago operating very successfully and for low running costs considering the heat losses involved.


Controls may have been like that on the units you were working on but we've been using weather compensation for 14yrs. There was far more wrong with poor installations back then than collectors. A certain Irish manufacturer for example had one mechanical stat in the heat pump which produced water to whatever level that stat was set for regardless of whether it was running underfloor heating or hot water. It was a disastrous system and I've replaced more of them than I'd care to count with very different results for the customer after the new system was installed.

KCross

sheff the ref wrote: »

I personally believe I will have to bite the bullet and go with a ground source heat pump with a borehole setup even though I have plenty room for a horizontal collector. The excavation costs are too messy and for a house of 1900 square feet, I am not going to be putting in a massive heatpump anyway

I will also have a stove in the house and to be honest, it also makes sense to have solar. I may not have all the sources in place from day one, but I will definitely have the provisions and plumbing etc. in place for them which makes sense.

Why would you add solar if you have a GSHP?
The €5k or whatever it is you spend on Solar will "never" get repaid.

A GSHP will easily provide you with all the hot water you need for €100/yr. Thats what I am seeing anyway. Do the multiplier on that and you will be a very long time getting back your solar costs.

Now, if the ESB allowed a feed-in tariff or if you were somehow storing unused energy etc you might justify it but I dont think that is in Ireland right now.

Maybe wire and plumb for it as a future proof for the house but dont blindly spend thousands on Solar without doing the maths on it.

BarneyMc

Condenser wrote: »

I mentioned on a thread here not 2 weeks ago the air tightness was not the end all and be all and there are plenty of houses we fitted units in 12yrs ago operating very successfully and for low running costs considering the heat losses involved.

"Very little correlation" is what you said rather than "end all and be all".

Last post at this page: http://www.boards.ie/vbulletin/showthread.php?t=2057564475

"Sorry Barney but that's utter rubbish. Airtightness and the performance of a heat pump or UFH have very little correlation. Its up there with the myth that air to water units will last 20yrs. A low temperature distribution system can almost guarantee a high performance heat pump system. There's houses built in the 90's with not even a clue what air tightness was that have GSHP's and impressive running costs some even better than a lot of the modern systems you see being bandied about today even with ultra insulated, ultra air tight houses."

sgc86

Hi

just wondering did you go for the air to water pump in the end?? If so do you have an average bill amount? just trying to budget - we have bought a new build that comes with this system as well as solar panels
Any info would be helpful Thanks

MENACE2010

sgc86 wrote: »

Hi

just wondering did you go for the air to water pump in the end?? If so do you have an average bill amount? just trying to budget - we have bought a new build that comes with this system as well as solar panels
Any info would be helpful Thanks

It's depending on the house.. We have an average of 170 euro per month...calculated over 12 months. I signed up with airtricity they have a payment plan based on average that takes the sting out of the peak bills .. You end up paying per month rather than two months . as stated heat pumps are not always cheaper or better than oil. One of the reasons we picked this as I was sick of oil.. Running out of oil on the moment you least expect it ..

jayoerris

MENACE2010 wrote: »

It's depending on the house.. We have an average of 170 euro per month...calculated over 12 months. I signed up with airtricity they have a payment plan based on average that takes the sting out of the peak bills .. You end up paying per month rather than two months . as stated heat pumps are not always cheaper or better than oil. One of the reasons we picked this as I was sick of oil.. Running out of oil on the moment you least expect it ..

Is that 170 per month for all electricity or just for heat pump?

MENACE2010

jayoerris wrote: »

Is that 170 per month for all electricity or just for heat pump?

Sorry that's everything.. Lights / pc / tv / game console / cooking

Condenser

sheff the ref wrote: »

I personally believe I will have to bite the bullet and go with a ground source heat pump with a borehole setup even though I have plenty room for a horizontal collector. The excavation costs are too messy and for a house of 1900 square feet, I am not going to be putting in a massive heatpump anyway

I will also have a stove in the house and to be honest, it also makes sense to have solar. I may not have all the sources in place from day one, but I will definitely have the provisions and plumbing etc. in place for them which makes sense.

As Kcross mentioned. Don't bother with solar. Its a waste of money. Wire for and possibly mount brackets for a PV array if you want to run for zero in the future but I'd hold off on that now and invest in a good GSHP.
A vertical bore on a smaller heat pump is not much more expensive than using a horizontal system if at all. Just make sure the bores you are getting are done correctly complete with probe placement (40mm single loop or 32mm double loop, grouting etc.)

sheff the ref

Condenser wrote: »

As Kcross mentioned. Don't bother with solar. Its a waste of money. Wire for and possibly mount brackets for a PV array if you want to run for zero in the future but I'd hold off on that now and invest in a good GSHP.
A vertical bore on a smaller heat pump is not much more expensive than using a horizontal system if at all. Just make sure the bores you are getting are done correctly complete with probe placement (40mm single loop or 32mm double loop, grouting etc.)

Interesting that the feedback here is to avoid the investment in solar if using a Ground Source heatpump.

Point noted

Big Dec

I have a question regarding solar gain & heating which I have noticed recently in relation to my own house.
I'm only in the house since end of October & still tweaking the GSHP settings.
With our typical Irish weather we can have sun for a portion of the day & then it can be quite cold once the sun has gone down.
A few times, I have come home to a warm house due to solar gain, but when the temperature drops it takes the UFH quite a while to bring it back up to temperature as the UFH in that area (and most of the house in fact) has been off since the previous night.
Anyone have any experience with this?
We like to have the sunroom a bit warmer as this is our main living room, just off the kitchen.
Could I set the stat to be a high temp (to ensure zone is opened) earlier in the day to charge up the floor in that area, before dropping it back to the desired temperature a while later.
The sunroom has a vaulted ceiling with a log of glass, so does heat up quickly with the sun & also loses the heat a little faster than the rest of the house.

Calahonda52

Why is the rig off at night? UFH is not an on off system, especially in a glasshouse
Are u on night rate elec?

Big Dec

I was missing details.
I have the stats set to drop back by ~2C from about 11pm so there is little or no demand on the heat pump.
Rest of house takes very little input from UFH to maintain a constant temperature throughout the day/night.
All other areas of the house maintain their temperature pretty well, so it is only the sunroom which drops off.
The room is ~ 5m x 4m with a 2m x 1.5m window on each side and a large arched window on outside gable which has ~12m2 of glazing.
In an ideal scenario, I would have reduced the sunroom glazing by at least a factor of 2 which would be more conducive to maintaining a constant temperature, but I wanted a bright & light filled room.
Just wondering if others have similar experiences.

g1983d

Big Dec wrote: »

I was missing details.
I have the stats set to drop back by ~2C from about 11pm so there is little or no demand on the heat pump.
Rest of house takes very little input from UFH to maintain a constant temperature throughout the day/night.
All other areas of the house maintain their temperature pretty well, so it is only the sunroom which drops off.
The room is ~ 5m x 4m with a 2m x 1.5m window on each side and a large arched window on outside gable which has ~12m2 of glazing.
In an ideal scenario, I would have reduced the sunroom glazing by at least a factor of 2 which would be more conducive to maintaining a constant temperature, but I wanted a bright & light filled room.
Just wondering if others have similar experiences.

Have you thought about the nest thermostats?
They learn your habits e.g. dropping temp at a certain time.
They also know the outside temp and how long it takes to get to your desired temp depending on the outside temp.
This would automatically turn on the UFH earlier or later to maintain your desired temp

ShanE90

Big Dec wrote: »

I have a question regarding solar gain & heating which I have noticed recently in relation to my own house.
I'm only in the house since end of October & still tweaking the GSHP settings.
With our typical Irish weather we can have sun for a portion of the day & then it can be quite cold once the sun has gone down.
A few times, I have come home to a warm house due to solar gain, but when the temperature drops it takes the UFH quite a while to bring it back up to temperature as the UFH in that area (and most of the house in fact) has been off since the previous night.
Anyone have any experience with this?
We like to have the sunroom a bit warmer as this is our main living room, just off the kitchen.
Could I set the stat to be a high temp (to ensure zone is opened) earlier in the day to charge up the floor in that area, before dropping it back to the desired temperature a while later.
The sunroom has a vaulted ceiling with a log of glass, so does heat up quickly with the sun & also loses the heat a little faster than the rest of the house.

Firstly I would be checking the balance of the system it's possible the flow is being directed elsewhere and the sunroom isn't getting enough when required. Also check the location on the thermostat...that's it's not in sunlight as this will hold the zone off for longer,

I'd also not have any setback at night. If your on night rate then you should really not have setback as you want to get the best out of the low tarrif by charging the slab of concrete up more during the night, the extra heat can then dissipate during the day. Bedrooms may be the exception as you don't want the room too warm while sleeping.

Also are you at a fixed set point for supply water, you may consider running on a heat curve if your HP supports this.

Big Dec

Sorry, have not been online for a bit.
Thanks for feedback.
As with all posts here, it looks like every house behaves differently & you just have to tweak the system as per your requirements.

@Calahonda52
When I mentioned about the UFH being off since previous night, I meant that there was no demand from any of the zones.

@g1983d
The system already has weather compensation built in.
My issue is that OH likes the sunroom "toasty" in the evening, but that means that the kitchen gets quite warm too as there is a big opening between the two rooms. Kitchen has tiles & sunroom has laminate so there is a faster heating response from kitchen.
I don't want the kitchen to be too warm during the day.

@ShanE90
There is plenty of flow directed to the sunroom as no other zones are generally calling for heat.
Due to all the glazing in the sunroom, it heats up pretty quickly during the day, but I think there is then a lag between when the sun goes down & the UFH kicks in & gets the room to temperature.
Unfortunately I am at a fixed set point for the supply water. I was playing around with the installer SW yesterday & there does seem to be an option to control the flow temp. Is that what you were referring to? I could then increase that for a certain period of the day & reduce back to nominal value.
I might also play a bit with charging the slab up a bit more during the night & not reducing temp at all in there.

ShanE90

Big Dec wrote: »

Sorry, have not been online for a bit.
Thanks for feedback.
As with all posts here, it looks like every house behaves differently & you just have to tweak the system as per your requirements.

@Calahonda52
When I mentioned about the UFH being off since previous night, I meant that there was no demand from any of the zones.

@g1983d
The system already has weather compensation built in.
My issue is that OH likes the sunroom "toasty" in the evening, but that means that the kitchen gets quite warm too as there is a big opening between the two rooms. Kitchen has tiles & sunroom has laminate so there is a faster heating response from kitchen.
I don't want the kitchen to be too warm during the day.

@ShanE90
There is plenty of flow directed to the sunroom as no other zones are generally calling for heat.
Due to all the glazing in the sunroom, it heats up pretty quickly during the day, but I think there is then a lag between when the sun goes down & the UFH kicks in & gets the room to temperature.
Unfortunately I am at a fixed set point for the supply water. I was playing around with the installer SW yesterday & there does seem to be an option to control the flow temp. Is that what you were referring to? I could then increase that for a certain period of the day & reduce back to nominal value.
I might also play a bit with charging the slab up a bit more during the night & not reducing temp at all in there.

As you describe the setup you have quite a bit of solar gain during the day and when the sun goes in the room cools down. Then by the time the thermostat has called for the zone to open its unable to heat the area in time due to it being UFH which is slow reacting. Can you increase the set point of the room at night so it has more heat to give off during the day, I would do this first turn it up fairly high until you get the temp you want then turn it back degree at a time until you know where is good.

Unfortunately due to the slow reaction of UFH and the quick rise in temps with solar gain you may find it difficult to get right, if you were in a position to put in a fan assisted radiator like a smart rad which could deal with the changing heat load much faster than UFH can it may suit the sunroom better.

sheff the ref

How are people managing their heat for times of the year where heat requirement is intermittent.

For instance in April/May and August/September, there may be periods where no heat is required due to warm temperatures and then you might have cold evenings, and then maybe warm temperatures again. Essentially the heating is turned off and a shot of heat may be needed the odd evening. With oil and rads this is possible, but what options are there for a heatpump and underfloor? Are people using other sources of heat for such 'out of heat season' cold evenings?

MENACE2010

sheff the ref wrote: »

How are people managing their heat for times of the year where heat requirement is intermittent.

For instance in April/May and August/September, there may be periods where no heat is required due to warm temperatures and then you might have cold evenings, and then maybe warm temperatures again. Essentially the heating is turned off and a shot of heat may be needed the odd evening. With oil and rads this is possible, but what options are there for a heatpump and underfloor? Are people using other sources of heat for such 'out of heat season' cold evenings?

Hey
We have a stove.5kw version. Heats up the living area. I tried hardwood logs but since converted to compressed saw dust logs. Better performance once the stove is hot we can burn one of these logs every two hours. .if we do more the house gets too hot ..
I leave the heat pump on and set cut off temperature to 18 degrees once it hits that outside the pump will not kick in

Shefwedfan

Hi, putting in solar panels. Going with company who supply Kingspan panels as they seem to be the best.

They have said they use the following pumps, any idea if they are good?


We supply the Neura and Jifon Ranges of heat pumps. The Jifon AirGO is great for retrofit projects, the Neura range are best in class heat pumps from Austria – they have the highest efficiencies on the HARP database for their classes.

mrsWhippy

Hi all,

We're in the process of getting quotes for an Air to water heat pump for a new build.

What is the best way to compare and contrast the various makes and models? We want to make sure we have a modern unit, low noise which has the best efficiency possible.

If anyone could PM me the details of a reliable provider/installer of renewable technologies also, it'd be appreciated.

Thanks

corcadorcha

Interested here also in info please.
Thanks.