Heat Pumps - post here.

Calahonda52

GraceKav wrote: »

....... Planning a 211m2 bungalow with UFH/ASHP/MVHR. ......

This just looks all wrong: you are shelling out serious mula, may 400k plus, on a build that is inherently flawed from an energy design perspective because your arch does not understand the way a MHVR works..
Loose the UFH and the HP and put the money towards getting close to Passiv Haus Standard, which can be heated for next to nothing with the MHVR and maybe a small wood pellet stove, not multi fuel if you want the PH cert, not needed, see below.
Use PV to get past the Renewables requirement.

MHVR extracts from the wet rooms and supplies to the rooms that need heat, which are already going to be hot with the UFH.......

Get a decent MHVR unit, c/w a cooling fan coil to take out the humidity in those humid summer days when the summer bypass is on, make sure yours has one.
Consider getting another elec heated fan coil unit to boost the supply from the MHVR on those cooler days.

The above maybe breach the strict PH elec energy footprint requirements but I did not say get the PH cert, just adopt the methodology for A/T and Insulation.

sheff the ref

There is a very good article on heatpumps here

http://www.irishexaminer.com/lifestyle/homeandinteriors/homehelp/upgrading-your-home-heating-system-376263.html

MENACE2010

GraceKav wrote: »

Looking for opinions on the below if anyone has any insight. Have done as much online digging as I can so far and will be sitting down to ask our architect this week but always good to get some different perspectives too.

Going for planning in the next few weeks so finalising house plans. Planning a 211m2 bungalow with UFH/ASHP/MVHR. Our architect is advising us to put the ASHP in the shed which will be approx 16-25m from the house. I need to check with them if this is a monoblock or split system. The shed was originally meant to be much nearer the house but was pushed back based on our request. I have an option to put an extra 70cmx200cm onto the laundry room (pulling from the sitting room which doesn't need the space) which would, based on my reading, give enough space to have a split system attached to the house rather than the shed. Just wondering what peoples' views are on this set up vs the original setup?



Some of the factors I've come up with based on my own research are:
- If have it in the shed, would need to insulate the piping into the house to prevent heat loss (have seen estimates of approx €40p/m on another thread)
- If we put it onto the house, it will be only 3-6m from the bedrooms and I believe some people have had issues with noise
- It would also be only 1-2m from the back door and I've seen comments from another reader that this can catch you with a blast of air every time you enter/exit
- A friend of ours has their unit in the utility and she raves about how quickly the clothes dry due to the piping etc - not sure if this would be the case for everyone as I didn't think the unit gave off that much ambient heat itself but definitely a plus if true
- Would prefer the unit indoors so that if we have to adjust we don't have to walk all the way outside
- Would worry that if the temp drops below freezing, we would be at more risk of pipes freezing etc if we had the unit in the shed particularly if we were away for a week or two and turned the unit off

Would welcome any feedback on the above as well as any estimated cost variances between the two options as well as maintenance issues. Any feedback on monoblock vs split would also be appreciated as I can't seem to find much opinion between the two options online except for the below Boards thread which is 5 years old and therefore may not be accurate today.

http://www.boards.ie/vbulletin/showthread.php?t=2056584700

Thanks in advance for the help.

Hi ,
we have a "plant room" at the side of the house where we have housed the ventialation , Heatpump, watercylinder and all other stuff that deals with the house mechanicals as i had to point out to the architect as well that we ran out of space in the copious designed utility room ..the plant room is about 4 sqm with a window in it and drain pipe in the floor for those situations that causes water overflow .. ( it happened , expansion tank failed water seeped in the drain instead of the room) .
about the location bear in mind the closer you keep the heat source to the house less loss it really that simple ..
. We have an Air Source heat pump , mounted on the concrete footpath around the house not on the wall of the house to mitigate vibration . The supplier of the heat pump recommends to use flexible hose to the heat exchanger but our plumber mounted it with fixed piping .. the noise is not that awful ( we have triple glazing and the pump is not around the window of any bedroom) but it will increase when its colder !! bear that in mind .. the colder it gets outside the harder the compressor will work -= more noise ..

if possible insulate the living daylight out of the house.. that is all i can advise you ( triple glazing, insulated plasterboard etc ).. it will keep the bills down, go for spread payment with your electricity provider so you have a fixed fee through the year. ( we are currently paying 130 euro a month it is reviewed every 6 months, its easier to manage)

good luck with your build..

hero25

GraceKav wrote: »

Looking for opinions on the below if anyone has any insight. Have done as much online digging as I can so far and will be sitting down to ask our architect this week but always good to get some different perspectives too.

Going for planning in the next few weeks so finalising house plans. Planning a 211m2 bungalow with UFH/ASHP/MVHR. Our architect is advising us to put the ASHP in the shed which will be approx 16-25m from the house. I need to check with them if this is a monoblock or split system. The shed was originally meant to be much nearer the house but was pushed back based on our request. I have an option to put an extra 70cmx200cm onto the laundry room (pulling from the sitting room which doesn't need the space) which would, based on my reading, give enough space to have a split system attached to the house rather than the shed. Just wondering what peoples' views are on this set up vs the original setup?

Some of the factors I've come up with based on my own research are:
- If have it in the shed, would need to insulate the piping into the house to prevent heat loss (have seen estimates of approx €40p/m on another thread)
- If we put it onto the house, it will be only 3-6m from the bedrooms and I believe some people have had issues with noise
- It would also be only 1-2m from the back door and I've seen comments from another reader that this can catch you with a blast of air every time you enter/exit
- A friend of ours has their unit in the utility and she raves about how quickly the clothes dry due to the piping etc - not sure if this would be the case for everyone as I didn't think the unit gave off that much ambient heat itself but definitely a plus if true
- Would prefer the unit indoors so that if we have to adjust we don't have to walk all the way outside
- Would worry that if the temp drops below freezing, we would be at more risk of pipes freezing etc if we had the unit in the shed particularly if we were away for a week or two and turned the unit off

Would welcome any feedback on the above as well as any estimated cost variances between the two options as well as maintenance issues. Any feedback on monoblock vs split would also be appreciated as I can't seem to find much opinion between the two options online except for the below Boards thread which is 5 years old and therefore may not be accurate today.

http://www.boards.ie/vbulletin/showthread.php?t=2056584700

Thanks in advance for the help.

we recently completed a 3200 sq ft house, so if i can help by giving my experience....
we have A2W with UFH on both first and 2nd floor.

I believe the Heatpump has to be outside - getting the air!
We placed our heatpump ~20m away from the house, for similar reasons to yourself. While the most efficient place is seemingly close to the water tank and control unit (makes sense)... we didn't like the aesthetics of outside the back door, it does make noise and would have been underneath/close to a bedroom.
Your costs for that insulated pipe are right, ~40euro/m. So we may be losing some heat and money in the 20m run to the house, but in our opinion, it's worth it. Our plumber wouldn't place the Heatpump any further than ~20m from the water tank/control unit- too inefficient.
He also wouldn't place the internal water tank and control unit in the garage (we did ask) - as he explained, any time hot water was needed in the house (for showers, UFH heating etc) - it would take too long to get to the house and if we were to do that, we would have needed another buffer tank in the house. Someone above posted similar comments. So we placed the tank and the internal unit indoors in utility room. It all fits in <1metre wide, tall press.

you're right re it doesn't generate huge heat itself, but the manifold (and washing machine and/or tumble dryer) does generate some heat - hence the utility room does end up being warm and is good for drying clothes.

hope that helps;)

caddy16

Currently researching for a new build - for people who have a heat pump with UFH how has it worked over the last week or 2.
As in I've had to turn on oil central heating in current house for an hour in the mornings and evenings due to the drop in temp - is your heating constantly on at a set temp?

Just trying to figure out the practicalities of a system I've no experience of.

KCross

caddy16 wrote: »

Currently researching for a new build - for people who have a heat pump with UFH how has it worked over the last week or 2.
As in I've had to turn on oil central heating in current house for an hour in the mornings and evenings due to the drop in temp - is your heating constantly on at a set temp?

Just trying to figure out the practicalities of a system I've no experience of.

Mine (Nibe Geothermal) usually comes on around the 2nd or 3rd week of Sept. It went off again for a few days earlier in the week but is on again now.

It decides based on the average temperature over a 24hr period. If that average drops below a set value it comes on. The idea is that the house remains at the same temp, which it generally does.

In another few weeks when the average temp drops further it will stay on 24/7. It doesn't work like a traditional oil system where you give it a blast for an hour.

caddy16

KCross wrote: »

Mine (Nibe Geothermal) usually comes on around the 2nd or 3rd week of Sept. It went off again for a few days earlier in the week but is on again now.

It decides based on the average temperature over a 24hr period. If that average drops below a set value it comes on. The idea is that the house remains at the same temp, which it generally does.

In another few weeks when the average temp drops further it will stay on 24/7. It doesn't work like a traditional oil system where you give it a blast for an hour.

Thanks Kcross, appreciate the response. So is your until "on" all year round but only kicks in when required on avg temps as you mentioned above?

KCross

caddy16 wrote: »

Thanks Kcross, appreciate the response. So is your until "on" all year round but only kicks in when required on avg temps as you mentioned above?

Yes, its a fully automated system. You don't turn it on/off like oil heating.

The unit is actually powered on 365 days of the year because it also heats the water each day but it automatically turns off the space heating once the avg temp drops below the set value so it turns off the circulating pumps relating to the space heating (i.e. the UFH pump) and continues to heat hot water as required each day.

caddy16

KCross wrote: »

Yes, its a fully automated system. You don't turn it on/off like oil heating.

The unit is actually powered on 365 days of the year because it also heats the water each day but it automatically turns off the space heating once the avg temp drops below the set value so it turns off the circulating pumps relating to the space heating (i.e. the UFH pump) and continues to heat hot water as required each day.

Makes sense, thanks. Do you find the system reacts adequately at this time of year when temps fluctuate or have you an alternative source such as a stove?

Sorry for all the questions!

KCross

caddy16 wrote: »

Makes sense, thanks. Do you find the system reacts adequately at this time of year when temps fluctuate or have you an alternative source such as a stove?

Sorry for all the questions!

It reacts fine. It uses what they call "weather compensating control". It has an outdoor stat so it knows the outdoor temp and will come on in advance to ensure that the house temp is maintained.

With UFH it takes several hours for the heat to build up and be released so there is no point coming on when the house temp has dropped, as thats too late. It comes on when the outside temp drops which gives it the few hours head start to cover the heat loss that the house will suffer in the hours ahead that day. It works.

My house is at 21C 24/7. You can adjust that up/down to suit your needs.

Note, my system is geothermal. There is also air-to-water heat pump systems.
The balancing act is the once off higher capital cost of geothermal vs the higher running and maintenance costs of air-to-water.

I have a kWh meter on my heat pump and it cost exactly €696 in electricity to cover all heating and hot water from Sep 16-Sep 17 in a 350m2 house.

MENACE2010

caddy16 wrote: »

Currently researching for a new build - for people who have a heat pump with UFH how has it worked over the last week or 2.
As in I've had to turn on oil central heating in current house for an hour in the mornings and evenings due to the drop in temp - is your heating constantly on at a set temp?

Just trying to figure out the practicalities of a system I've no experience of.

Hi , ours is still off in that it only generates hotwater for now . we have lit a stove the house but thats only in the evening when we are there but Its more to get rid of the "chill" .. as posted previously the better the insulation is the longer you can do without heating . , We are now 4 yrs in the house and are very happy .
D.

caddy16

KCross wrote: »

It reacts fine. It uses what they call "weather compensating control". It has an outdoor stat so it knows the outdoor temp and will come on in advance to ensure that the house temp is maintained.

With UFH it takes several hours for the heat to build up and be released so there is no point coming on when the house temp has dropped, as thats too late. It comes on when the outside temp drops which gives it the few hours head start to cover the heat loss that the house will suffer in the hours ahead that day. It works.

My house is at 21C 24/7. You can adjust that up/down to suit your needs.

Note, my system is geothermal. There is also air-to-water heat pump systems.
The balancing act is the once off higher capital cost of geothermal vs the higher running and maintenance costs of air-to-water.

I have a kWh meter on my heat pump and it cost exactly €696 in electricity to cover all heating and hot water from Sep 16-Sep 17 in a 350m2 house.

Really appreciate that. Need to do my sums now on the capital outlay V running costs on the size of system I need.

KCross

caddy16 wrote: »

Really appreciate that. Need to do my sums now on the capital outlay V running costs on the size of system I need.

Best of luck with that!

There is no easy way to figure that out. It requires a crystal ball!

At a high level these are the main considerations
Capital costs
- Geothermal heat pump will be more expensive than A2W heat pump.
- Geo requires a collector which can be horizontal or vertical and costs will vary depending on which is required which is dependent on site survey.

The above will be easy to compare once you get quotes in and A2W will be cheaper, no question of that. The difficult bit is deciding if the extra outlay is worth it in the long run (see maintenance below)


Running/Maintenance costs
- Geo will cost less in electricity than A2W. How much less is impossible to tell as it will vary by house, by installer, by system used etc. Anything from 100-800/yr difference would be a rough guide.
- Geo on average should cost less on repairs as there is less to go wrong in them.
- Geo should last longer than A2W because its not outside, exposed to weather and frost etc., and the compressor etc is not running as often as the A2W one will be, so by definition the A2W unit will burn out first. A2W compressor to die in maybe 10-15yrs and the Geo one in 15-25yrs.... Again, rough guide and its like a car... you can't really predict how long it will last and you could be lucky/unlucky with either system.
- The most difficult one to quantify is that the A2W is unlikely to last beyond 15yrs and you could find that you need to replace the entire unit and not just a compressor. All things being equal it definitely won't last longer than the Geo unit so some of that extra initial capital outlay on Geo is buying you longevity and less hassle so you need to look at total cost of ownership and not just capital cost comparison.


One other thing is that A2W is noisier (outdoor fan) so consider where that will be placed and if it will disturb people sleeping or neighbours.


Both systems will give you the same end result in the house in relation to space heating and hot water so from a comfort perspective I think both will be the same.


The above is my experience based on my research and having a Geo system. Others may disagree but I don't think I'm far out.

hero25

based on my experience, KCross has given very good, precise information. I've an A2W, in the house 18months and would agree with KCross comments. this ill be our 2nd winter here so am still adjusting the settings...
we've set the standing temp to 18 degrees and as we're gone all day ... we've set the UFH to "boost" to 21degrees from 4-7am and again 6pm-10pm. the UFH can be slow to get up to temperature, hence the 3-4 hour durations.
as described already, it only kicks in when necessary .... no need for 21degrees when nobody's here!
so far in september our heating "section" of the heat pump has been on for 12 hours. house is toasty!

caddy16

KCross wrote: »

Best of luck with that!

There is no easy way to figure that out. It requires a crystal ball!

At a high level these are the main considerations
Capital costs
- Geothermal heat pump will be more expensive than A2W heat pump.
- Geo requires a collector which can be horizontal or vertical and costs will vary depending on which is required which is dependent on site survey.

The above will be easy to compare once you get quotes in and A2W will be cheaper, no question of that. The difficult bit is deciding if the extra outlay is worth it in the long run (see maintenance below)


Running/Maintenance costs
- Geo will cost less in electricity than A2W. How much less is impossible to tell as it will vary by house, by installer, by system used etc. Anything from 100-800/yr difference would be a rough guide.
- Geo on average should cost less on repairs as there is less to go wrong in them.
- Geo should last longer than A2W because its not outside, exposed to weather and frost etc., and the compressor etc is not running as often as the A2W one will be, so by definition the A2W unit will burn out first. A2W compressor to die in maybe 10-15yrs and the Geo one in 15-25yrs.... Again, rough guide and its like a car... you can't really predict how long it will last and you could be lucky/unlucky with either system.
- The most difficult one to quantify is that the A2W is unlikely to last beyond 15yrs and you could find that you need to replace the entire unit and not just a compressor. All things being equal it definitely won't last longer than the Geo unit so some of that extra initial capital outlay on Geo is buying you longevity and less hassle so you need to look at total cost of ownership and not just capital cost comparison.


One other thing is that A2W is noisier (outdoor fan) so consider where that will be placed and if it will disturb people sleeping or neighbours.


Both systems will give you the same end result in the house in relation to space heating and hot water so from a comfort perspective I think both will be the same.


The above is my experience based on my research and having a Geo system. Others may disagree but I don't think I'm far out.

Cheers for taking the time for this. I understand on the calcs, some assumptions needed.

Have you UFH on both floors?

KCross

caddy16 wrote: »

Cheers for taking the time for this. I understand on the calcs, some assumptions needed.

Have you UFH on both floors?

No, over sized aluminium rads upstairs.
UFH everywhere is the better choice but I think it costs more as you need extra block work to support a concrete floor upstairs.

The alu rads are working fine so Im happy enough with that but the majority of our living is downstairs. Upstairs are bedrooms only which you don't need at the same temp anyway.

Water John

All you need for the UFH upstairs is about 50-75mm of either a dry mix or the liquid screed, on chipboard. Use 25mm of insulation between. You can use metal sheet pans instead to spread the heat, but they are dear.
Alu rads are fine too. The thermostats can be set low.

hero25

Water John wrote: »

All you need for the UFH upstairs is about 50-75mm of either a dry mix or the liquid screed, on chipboard. Use 25mm of insulation between. You can use metal sheet pans instead to spread the heat, but they are dear.
Alu rads are fine too. The thermostats can be set low.

not so sure about laying a screed on chipboard over joists that may not have spec'd for the weight...lot of weight in even a thin screed... i'd suggest get some advice from a structural engineer rather than a Boards forum ;-)
we used an "easi-joist" system, as UFH upstairs was an afterthought. they are wooden joists with special metal triangular supports built in and are designed for your house to take the load in your upstairs. seem a good job.

lolliedog

Hi all,

Currently building a new house (block built)

2300 sq ft
150mm cavity therm insulation
400mm quilt in attic
Triple glazed
airtightness
Mhrv
Underfloor heating downstairs rads upstairs


We are now choosing the heating systems and the choice is between an a2w heat pump or a gas boiler. We have natural gas passing our site?
I am aware that with gas there will be other considerations for part L. A gas boiler has some advantages.

Any feedback would be appreciated.

KCross

lolliedog wrote: »

We are now choosing the heating systems and the choice is between an a2w heat pump or a gas boiler. We have natural gas passing our site?
I am aware that with gas there will be other considerations for part L. A gas boiler has some advantages.

Any feedback would be appreciated.

With gas you will have another bill with another set of standing charges and levies. I doubt gas will be so cheap as to beat electricity when you take that into account as you will have to pay those charges all year round.

Also, have you considered Geothermal? You should at least get a quote for it.

lolliedog

KCross wrote: »

With gas you will have another bill with another set of standing charges and levies. I doubt gas will be so cheap as to beat electricity when you take that into account as you will have to pay those charges all year round.

Also, have you considered Geothermal? You should at least get a quote for it.

Thanks

In relation to geothermal, the site is small and access is restricted.

The simplicity if a gas boiler is appealing and the fact that it can modulate. A simple combi would meet my requirements.

One thing I like about A2w heat pumps is that some can run in reverse if the space in summer is overheated.

BryanF

lolliedog wrote: »

A simple combi would meet my requirements.
.

BER/ TGD part L requirements ?

lolliedog

BryanF wrote: »

BER/ TGD part L requirements ?

Solar PV and a wood burning stove to meet the requirements.

The gas option will have further considerations and expense but I can't ignore the simplicity of a gas boiler for space heating and dhw.

antoinolachtnai

If you could get one system, the a2w, and so avoid having to buy three other systems ( pv, gas and stove) it seems like a time, money and maintenance saver.

A lot depends on how much energy your home will actually require to heat.

lolliedog

antoinolachtnai wrote: »

If you could get one system, the a2w, and so avoid having to buy three other systems ( pv, gas and stove) it seems like a time, money and maintenance saver.

A lot depends on how much energy your home will actually require to heat.

Hence the dilemma.

A good gas boiler €1000- 1200
A Stove (we are having anyway)

There is probably very little price variation but long term would the gas boiler win out.

I think the decisions nowadays are regulations driven.

antoinolachtnai

I think over the long term the A2W will win out because the unit cost of heat is lower (though up front cost is higher) .

But it really depends.

The regulations are certainly intended to drive you in a direction. They aren’t intended to save you money, certainly. They are intended to have an impact at macro level.

antoinolachtnai

I think over the long term the A2W will win out because the unit cost of heat is lower (though up front cost is higher) .

But it really depends.

The regulations are certainly intended to drive you in a direction. They aren’t intended to save you money, certainly. They are intended to have an impact at macro level.

lolliedog

antoinolachtnai wrote: »

I think over the long term the A2W will win out because the unit cost of heat is lower (though up front cost is higher) .

But it really depends.

The regulations are certainly intended to drive you in a direction. They aren’t intended to save you money, certainly. They are intended to have an impact at macro level.

I'm leaning in this direction.

One install, less to worry about on site and it ticks the relevant boxes.

antoinolachtnai

One other thing is to make sure your assessment of hot water requirements is right. You said that a combi would meet your needs. I cannot see how a combi could provide enough hot water for a house that size (unless one room is a basketball court maybe).

Gas boilers are extremely reliable but they are not at all simple. There is a lot to them. Installing gas pipe work is not cheap or simple either.

One way or the other you have to factor in the costs of tanks, pumps, etc.

Solid fuel has its costs too, in terms of storage, wear on soft furnishings and all the rest.

Nothing is simple or cheap!

lolliedog

antoinolachtnai wrote: »

One other thing is to make sure your assessment of hot water requirements is right. You said that a combi would meet your needs. I cannot see how a combi could provide enough hot water for a house that size (unless one room is a basketball court maybe).

Gas boilers are extremely reliable but they are not at all simple. There is a lot to them. Installing gas pipe work is not cheap or simple either.

One way or the other you have to factor in the costs of tanks, pumps, etc.

Solid fuel has its costs too, in terms of storage, wear on soft furnishings and all the rest.

Nothing is simple or cheap!

I researched the combi boiler and the vaillant 938 would meet all the requirements and then sum. Can run two showers at the one time with very good pressure. The boiler is oversized but this is due to the dhw requirements.